WO2012090195A1

WO2012090195A1 - An indoor wireless network with ceiling- mounted repeaters

Info

Publication number: WO2012090195A1
Application number: PCT/IL2011/000970
Authority: WO
Inventors: Sara MILANO; Refael Popovich; Stacy JOSEPH; Alberto Milano
Original assignee: Beam Networks Ltd.
Priority date: 2010-12-30
Filing date: 2011-12-29
Publication date: 2012-07-05

Abstract

An indoor wireless network that enables a cluster of users to communicate to each and every member of the cluster and to access points located in the indoor environment. To ensure line of sight intrusion, repeaters mounted on the ceiling will redirect EM wave's paths between tables, where equipment is located.

Description

An Indoor Wireless Network with Ceiling- Mounted Repeaters

REFERENCE TO CO-PENDING APPLICATIONS

Priority is claimed from US provisional application No. 61/457,108; filed December 30, 2010 and entitled "Retractable antennas for 60 GHz AESA transceivers as elements of an indoor network".

FIELD OF THE INVENTION

The present invention relates generally to communication networks and more particularly to indoor wireless networks.

BACKGROUND OF THE INVENTION

All known 60 GHz transceivers under development are based on digital technology (MIMO), except one which is based on AESA technology. As of 2010 only one digital- circuitry based product has been commercialized, while there is no information about previous 60 GHz home networks of transceivers. A 60 GHz indoor link between one transmitter and a number of receivers is known. However, it is not a bidirectional network.

The disclosures of all publications and patent documents mentioned in the specification, and of the publications and patent documents cited therein directly or indirectly, are hereby incorporated by reference.

SUMMARY OF THE INVENTION

Certain embodiments of the present invention seek to provide an indoor wireless network with ceiling- mounted repeaters.

Certain embodiments of the present invention seek to provide retractable antennas for 60 GHz AESA transceivers as elements of an indoor network.

There is thus provided, in accordance with at least one embodiment of the present invention, an indoor wireless network that enables a cluster or group of users of the network to communicate to at least some of and typically to each and every member of the cluster and to access points located in an indoor environment. To ensure line of sight intrusion, repeaters may be mounted on the ceiling and may redirect EM wave's paths between tables, where equipment used by the users is located.

• Circularly Polarized Phased Array antennae may be used to secure correct RF link/s among the users and the fixed network repeaters typically in any position of the network elements. This typically overcomes any geometrically misalignment between the receiving antenna to the transmitting one.

• Implementation of the transceiver of at least one individual laptop or desktop computer e.g. on the cover of the laptop or on the rear side of the desktop display typically in such a way that the RX and TX antennae are always close to parallel to the table when the laptop is either closed or open.

• RX and/or TX antennae may be provided as tablets retractable inside a laptop body or inside the display of a desktop.

• Electrical connection between the retractable tablets of RX and/or TX antennae and related TX and/or RX MW circuits may be realized by strip-line medium, implemented e.g. in flexible Liquid Chrystal Polymer laminates, or in any other flexible laminate suitable for the operating frequency.

• Retractable RX and TX antennas may have any suitable location e.g. on the surface of the front side, backside or whatever other side of the laptop cover or desktop display.

• The network may be installed in home environments where the floor is either parallel to the ceiling or tilted.

• For "fragmented" computers having physically separated parts or blocks, the transceiver may be implemented in every block or every significant (for the application) block of the fragmented computer.

• "Self Radio Link": the transmitter of at least one and typically every user may transmit, to the receiver of the same user, information from one part of his computer to another part thereof, using the network. The "self Radio Link" typically is operative to transmit / receive information to / from any possible separate functional block of the computer.

• Position on the ceiling and on the desks of the access point, repeaters and users in the network:"V" propagation directions for avoiding interruption of line of sight. • Also provided is a sequential procedure for establishing coherency conditions among all the network users, having as reference to the access point carrier frequency and phase.

The present invention typically includes at least the following embodiments:

Embodiment 1 : An Indoor network including Circularly Polarized Phased Array Transceivers, for securing correct RF link among the users and the fixed network repeaters in any position of the network elements.

Embodiment 2: Indoor network based on transmission and reception of EM waves between tables and ceiling of an indoor environment.

Embodiment 3: Implementation of the transceiver of at least one individual laptop or desktop computer e.g. on the cover of the laptop or on the rear side of the desktop display in such a way that the RX and TX antennas may always be parallel to the table when the laptop is closed as well as when the laptop is open.

Embodiment 4: RX and/or TX antennas as tablets retractable inside a laptop body or inside the display of a desktop.

Embodiment 5: Electrical connection between the retractable tablets of RX and/or TX antennas and related TX and/or RX MW circuits via strip-line medium, implemented in flexible Liquid Chrystal Polymer laminates, or in any other flexible laminate suitable for 60 GHz operations.

Embodiment 6: Retractable RX and TX antennas may have whatever location on the surface of the front side, backside or whatever other side of the laptop cover or the desktop display.

Embodiment 7: The network may be installed in home environments where the floor is parallel to the ceiling and also where the floor is not parallel to the ceiling.

Embodiment 8: In case of computers having different physically separated functions, the transceiver may be implemented in every significant block of the fragmented computer.

Embodiment 9: "Self Radio Link": the transmitter of every user may transmit to the receiver of the same user information from one part of his computer to another part of it, using the network. The "self Radio Link" may transmit / receive information to / from any possible separate functional block of the computer.

Embodiment 10: Position on the ceiling and on the desks of the access point, repeaters and users in the network:"V" propagation directions for avoiding interruption of line of sight.

Embodiment 11 : Sequential procedure of establishing coherency conditions among all the network users, having as reference to the access point carrier frequency and phase.

Embodiment 12: Master system e.g. as shown or illustrated herein.

Embodiment 13: Half master system e.g. as shown or illustrated herein.

Embodiment 14: Half slave system e.g. as shown or illustrated herein.

Embodiment 15: A method whereby a Half slave system becomes a half master system.

Embodiment 16: A method including Locking of each network element to any other network element directly or through a repeater or combination of repeaters and users.

Embodiment 17: A method including Locking of all network elements to the master access point transceiver.

Embodiment 18: Interoperability between AESA and MIMO based networks.

Embodiment 19. Interoperability according to claim 18 wherein the AESA master is acting as wireless access point of the signal generated by the dedicated interoperability MIMO transceiver, and distributed among the AESA users and repeaters without any further interaction with the MIMO network.

Embodiment 20. Apparatus according to claim 1 wherein said Circularly Polarized Phased Array Transceivers are as described in or are similar to or based on those described in co-owned United States Patent 7800453 to Alberto Milano entitled "Apparatus and methods for radar imaging based on injected push-push oscillators".

Embodiment 21. Any suitable combination of any of the systems herein with any of the systems described or illustrated in co-owned US Patent 7,852,265 to Milano and Weinstein.

Embodiment 22. Any suitable combination of any of the methods herein with any of the methods described or illustrated in co-owned US Patent 7,852,265 to Milano and Weinstein. Also provided is a computer program product, comprising a computer usable medium or computer readable storage medium, typically tangible, having a computer readable program code embodied therein, said computer readable program code adapted to be executed to implement or manage any or all of the methods shown and described herein. It is appreciated that any or all of the computational steps shown and described herein may be computer- implemented. The operations in accordance with the teachings herein may be performed by a computer specially constructed for the desired purposes or by a general purpose computer specially configured for the desired purpose by a computer program stored in a computer readable storage medium.

Any suitable processor, display and input means may be used to process, display e.g. on a computer screen or other computer output device, store, and accept information such as information used by or generated by any of the methods and apparatus shown and described herein; the above processor, display and input means including computer programs, in accordance with some or all of the embodiments of the present invention. Any or all functionalities of the invention shown and described herein may be performed by a conventional personal computer processor, workstation or other programmable device or computer or electronic computing device, either general-purpose or specifically constructed, used for processing; a computer display screen and/or printer and/or speaker for displaying; machine-readable memory such as optical disks, CDROMs, magnetic-optical discs or other discs; RAMs, ROMs, EPROMs, EEPROMs, magnetic or optical or other cards, for storing, and keyboard or mouse for accepting. The term "process" as used above is intended to include any type of computation or manipulation or transformation of data represented as physical, e.g. electronic, phenomena which may occur or reside e.g. within registers and /or memories of a computer.

The above devices may communicate via any conventional wired or wireless digital communication means, e.g. via a wired or cellular telephone network or a computer network such as the Internet.

The apparatus of the present invention may include, according to certain embodiments of the invention, machine readable memory containing or otherwise storing a program of instructions which, when executed by the machine, implements some or all of the apparatus, methods, features and functionalities of the invention shown and described herein. Alternatively or in addition, the apparatus of the present invention may include, according to certain embodiments of the invention, a program as above which may be written in any conventional programming language, and optionally a machine for executing the program such as but not limited to a general purpose computer which may optionally be configured or activated in accordance with the teachings of the present invention. Any of the teachings incorporated herein may wherever suitable operate on signals representative of physical objects or substances.

The embodiments referred to above, and other embodiments, are described in detail in the next section.

Any trademark occurring in the text or drawings is the property of its owner and occurs herein merely to explain or illustrate one example of how an embodiment of the invention may be implemented.

Unless specifically stated otherwise, as apparent from the following discussions, it is appreciated that throughout the specification discussions, utilizing terms such as, "processing", "computing", "estimating", "selecting", "ranking", "grading", "calculating", "determining", "generating", "reassessing", "classifying", "generating", "producing", "stereo-matching", "registering", "detecting", "associating", "superimposing", "obtaining" or the like, refer to the action and/or processes of a computer or computing system, or processor or similar electronic computing device, that manipulate and/or transform data represented as physical, such as electronic, quantities within the computing system's registers and/or memories, into other data similarly represented as physical quantities within the computing system's memories, registers or other such information storage, transmission or display devices. The term "computer" should be broadly construed to cover any kind of electronic device with data processing capabilities, including, by way of non-limiting example, personal computers, servers, computing system, communication devices, processors (e.g. digital signal processor (DSP), microcontrollers, field programmable gate array (FPGA), application specific integrated circuit (ASIC), etc.) and other electronic computing devices.

The present invention may be described, merely for clarity, in terms of terminology specific to particular programming languages, operating systems, browsers, system versions, individual products, and the like. It will be appreciated that this terminology is intended to convey general principles of operation clearly and briefly, by way of example, and is not intended to limit the scope of the invention to any particular programming language, operating system, browser, system version, or individual product.

BRIEF DESCRIPTION OF THE DRAWINGS

Certain embodiments of the present invention are illustrated in the following drawings:

Fig. 1 illustrates a wireless network using 60 GHz AESA transceivers wherein each computer on each of several desks has a dedicated transceiver, typically embedded inside the laptop or desktop, and Repeaters are installed on the ceiling of the indoor environment, all in accordance with certain embodiments of the present invention.

Fig. 2 shows apparatus including a laptop with open cover (cover and antennae opening being mechanically linked), with retractable tablets on the upper part, in operative association with a repeater including e.g. transmitter/receiver, all in accordance with certain embodiments of the present invention, which apparatus may be used, inter alia, for sharing input information coming from access point to all users, allowing a pair of network users to transfer data between each other, allowing a user to send his information to several members, allowing several user pairs to use the network, each pair simultaneously sending different information, and other uses.

Fig. 3 illustrates a transceiver which is operational when the cover is closed (cover and antennae opening being mechanically linked), e.g. if a user prefers to use his laptop through a docking station, all in accordance with certain embodiments of the present invention.

Fig. 4 describes a wireless network using 60 GHz AESA transceivers, e.g. embedded inside a laptop or desktop, in which every computer on the desks has a dedicated transceiver and wherein access point and repeater equipment may be installed on the ceiling of the indoor environment, all in accordance with certain embodiments of the present invention.

Fig. 5 illustrates a receiver subsystem, which may comprise common part to access point, repeater and user transceivers, all in accordance with certain embodiments of the present invention.

Fig. 6 illustrates a transmitter subsystem, which may comprise common part to access point, repeater and user transceivers, all in accordance with certain embodiments of the present invention. Fig. 7 illustrates an access point system typically including some or all of a Ί7Χ, R/X, 15 GHz reference signal generator, input baseband subsystem and output baseband subsystem, all in accordance with certain embodiments of the present invention.

Fig. 8 illustrates an embodiment of the invention, also termed herein the " access point master / same hardware as user - half master - half slave" embodiment, comprising a repeater system including some or all of: T/X, R/X and 15 GHz reference signal generator, all constructed and operative in accordance with certain embodiments of the present invention.

It is appreciated that terminology such as "mandatory", "required", "need" and "must" refer to implementation choices made within the context of a particular implementation or application described herewithin for clarity and are not intended to be limiting since in an alternative implantation, the same elements might be defined as not mandatory and not required or might even be eliminated altogether.

It is appreciated that software components of the present invention including programs and data may, if desired, be implemented in ROM (read only memory) form including CD- ROMs, EPROMs and EEPROMs, or may be stored in any other suitable computer-readable medium such as but not limited to disks of various kinds, cards of various kinds and RAMs. Components described herein as software may, alternatively, be implemented wholly or partly in hardware, if desired, using conventional techniques. Conversely, components described herein as hardware may, alternatively, be implemented wholly or partly in software, if desired, using conventional techniques.

Included in the scope of the present invention, inter alia, are electromagnetic signals carrying computer-readable instructions for performing any or all of the steps of any of the methods shown and described herein, in any suitable order; machine-readable instructions for performing any or all of the steps of any of the methods shown and described herein, in any suitable order; program storage devices readable by machine, tangibly embodying a program of instructions executable by the machine to perform any or all of the steps of any of the methods shown and described herein, in any suitable order; a computer program product comprising a computer useable medium having computer readable program code, such as executable code, having embodied therein, and/or including computer readable program code for performing, any or all of the steps of any of the methods shown and described herein, in any suitable order; any technical effects brought about by any or all of the steps of any of the methods shown and described herein, when performed in any suitable order; any suitable apparatus or device or combination of such, programmed to perform, alone or in combination, any or all of the steps of any of the methods shown and described herein, in any suitable order; electronic devices each including a processor and a cooperating input device and/or output device and operative to perform in software any steps shown and described herein; information storage devices or physical records, such as disks or hard drives, causing a computer or other device to be configured so as to carry out any or all of the steps of any of the methods shown and described herein, in any suitable order; a program pre-stored e.g. in memory or on an information network such as the Internet, before or after being downloaded, which embodies any or all of the steps of any of the methods shown and described herein, in any suitable order, and the method of uploading or downloading such, and a system including server/s and/or client/s for using such; and hardware which performs any or all of the steps of any of the methods shown and described herein, in any suitable order, either alone or in conjunction with software.

Any computations or other forms of analysis described herein may be performed by a suitable computerized method. Any step described herein may be computer-implemented. The invention shown and described herein may include (a) using a computerized method to identify a solution to any of the problems or for any of the objectives described herein, the solution optionally include at least one of a decision, an action, a product, a service or any other information described herein that impacts, in a positive manner, a problem or objectives described herein; and (b) outputting the solution.

Features of the present invention which are described in the context of separate embodiments may also be provided in combination in a single embodiment. Conversely, features of the invention, including method steps, which are described for brevity in the context of a single embodiment or in a certain order may be provided separately or in any suitable subcombination or in a different order, "e.g." is used herein in the sense of a specific example which is not intended to be limiting. Devices, apparatus or systems shown coupled in any of the drawings may in fact be integrated into a single platform in certain embodiments or may be coupled via any appropriate wired or wireless coupling such as but not limited to optical fiber,

Ethernet, Wireless LAN, HomePNA, power line communication, cell phone, PDA, Blackberry

GPRS, Satellite including GPS, or other mobile delivery. It is appreciated that in the description and drawings shown and described herein, functionalities described or illustrated as systems and sub-units thereof can also be provided as methods and steps therewithin, and functionalities described or illustrated as methods and steps therewithin can also be provided as systems and sub-units thereof. The scale used to illustrate various elements in the drawings is merely exemplary and/or appropriate for clarity of presentation and is not intended to be limiting.

DETAILED DESCRIPTION OF CERTAIN EMBODIMENTS

A communication network system is provided according to any embodiment of the invention, comprising a plurality of nodes at least one of which comprising a transceiver interfacing with an antenna which is operative to transmit and receive an electronically steerable focused electromagnetic beam. The beam is typically steerable using a phase shifting functionality provided by a PSIPPO (phase shift injected push push oscillator). A set or group of nodes is also termed herein a "cluster". Each transceiver may be based on transceiver technology known in the art e.g. as shown and described in US Patent 7,852,265 to Milano and Weinstein, entitled "Wireless area network compliant system and method using a phase array antenna".

Suitable transceiver technology is also described in: PCT/IL06/01144, entitled "PHASED SHIFTED OSCILATOR AND ANTENNA", PCT/IL06/01039, entitled "Apparatus and Methods For Radar Imaging Based on Injected Push-Push Oscillators", USP 7911373, entitled "Compact Active Phased Array Antenna For Radars", Published US Patent Application No. #20080272962, entitled "Wireless area network compliant system and method using a phase array antenna", and Published US Patent Application No. #20100188289 entitled "Communication system and method using an active phased array antenna".

The antenna is typically circularly polarized, as is known in the art, thereby to enable transmission and reception of an electromagnetic beam regardless of the spatial orientation of the transmitting and receiving transceivers. Typically, the antenna has a bandwidth of approximately 10% centered at approximately 60 GHz, e.g. a bandwidth of approximately 57 - 64 GHz.

The focused electromagnetic beam may be steered using AESA (active electronically scanned array) technology. For interoperability, the plurality of nodes may also include at least one MIMO node, e.g. based on relatively costly Sibeam or Wilocity (Caesarea, Israel) technology, which operate at 60 GHz but do not have a focussed beam. An example of a commercially available product of this type is the Silicon Image (formerly Sibeam) SiI9334 HDMI^® 1.4 Transmitter.

Typically, the plurality of nodes comprises at least one pair of nodes comprising first and second nodes which lack a line of sight between them, and, for each such pair, at least one repeater node having a line of sight to both of said first and second nodes. The at least one repeater node includes at least one repeater node serving more than one pair of nodes which lack a line of sight between them. A sequence of repeater nodes with a line of sight and less than a predetermined distance between them may serve each pair of nodes separated by more than the predetermined distance which may be, say, 10 meters.

A software management functionality is typically provided which is operative to enable simultaneous transmission and reception between more than one pair of nodes from among said plurality of nodes by dividing at least one transceiving resource between active nodes.

The software management functionality may employ any suitable technology, e.g. CDMA, TDMA or FDMA.

The applicability of certain embodiments of the present invention includes Wireless Personal Area Network architecture and related devices, (e.g. as per Fig. 1). The network ty comprises transceivers imbedded inside laptop or desktop computers and transceivers installed on the ceiling of the indoor open space as repeaters. The network is operative to establish a two way radio link among the many users in a home environment. The elements of the described network ty include AESA (Active Electronically Steered Antenna) transceivers. Using AESA technology the RF link between two network elements is ty operational only when the transceivers are in line of sight.

In a home environment with many users, line of sight between two users is not possible, because the users themselves act as obstacles to the line of sight: as is well known, human bodies completely dissipate 60 GHz signals. For this reason to set the RF link a repeater may be employed for bypassing the obstacles: for this purpose the transmission and reception of the 60 GHz signals in the described network may take place vertically, between the computer imbedded transceivers and the ceiling installed repeaters.

A vertical direction of the RF links may, according to some embodiments, require the RX and TX directive antennas of the users to be parallel to the floor and directed toward the ceiling; and the directive antennas of the repeaters to be parallel to the ceiling and directed toward the floor. The floor is usually parallel to the ceiling, but even in the opposite case the network may be successfully operational: AESA technology is able to overcome the problem using its beam steering ability.

The reciprocal parallel position of the computer-imbedded transceivers and the ceiling-installed repeaters is typically not sufficient per se to secure a viable RP link among the various network elements: instead the systems may handle circularly polarized EM waves.

Accordingly, simply linearly polarized transceivers ty secure the link only when all the transceivers are oriented toward the same direction of the transmitted and received linearly polarized EM waves. Any possible different orientation angle of a network element may end up with a parasitic attenuation of the received signal.

The signal received by a linearly-polarized computer-imbedded element, transmitter by a linearly polarized repeater with +/- 90 degrees reciprocal orientation, may be null. The same may occur for a ceiling-installed repeater transmitting toward a computer-imbedded element with +/- 90 degrees reciprocal orientation.

Therefore in order to allow the users to orient the computer antennas in whatever direction they may decide, all network elements may support circular polarization operations.

As every user can ty transmit / receive to / from any other user of the network, every user typically can transmit / receive to / from himself using the network. This feature can be useful if and when the various functions of a computer are physically separated having their own mechanical housing, e.g. are connected wirelessly. Using the structure of the network, every user ty has the possibility of transmitting / receiving to / from any individual block of the computer of every other user.

A Bidirectional telecommunication network ty comprises a system of wired or wireless transceivers, able to link each other. One specific case is the wideband 60 GHz wireless indoor network, used for high rate data transmission.

Wireless transceivers may for example either be based on MIMO, (Multiple Input Multiple Out), or on AESA (Active Electronically Steered Antenna). Networks based on AESA transceivers, and specifically those based on coherent down conversion, are described herein, by way of example. Coherent down conversion is a "direct" operation: that means the frequency of the local oscillator (LO) of the receiver (R/X) and the frequency of the Transmitter (T/X) carrier may be identical. Moreover the mentioned signals typically have 90 degrees difference in phase. Under those conditions the information may be "coherently" and "directly" converted to baseband.

To establish a coherent conversion between a single T/X and a single R/X, the frequency and phase of the T/X carrier may be the locking reference.

In order to make operational a network of several T/X and as many R X, all network elements may be compliant with the coherency conditions.

Setting coherency among the network elements, according to certain embodiments, is now described. First, an example of suitable Network element hardware is described. Access point 1400 typically has the same structure and hardware as the user transceivers, e.g. some or all of: a. MW part: Transmitter 1300 and Receiver 1200. b. Reference subsystem: XTAL oscillator 1401 and phase lock controlled 15 GHz VCO 1402. c. Digital Baseband subsystem for R/X 1406. d. Digital Baseband subsystem for T/X 1404.

The repeater transceiver ty has no digital baseband subsystems: in fact the repeating operations bypass baseband demodulation and modulation.

A "Half slave" may optionally turn into a "half master". With reference to Fig. 4, the master T/X typically locks the slave R/X with a phase lock loop, such that the slave frequency is identical to the master, and the phase is 90 degrees, as usually happens in coherent radio links. After the coherent link is established, the slave-located XTAL may be activated. Its frequency is typically unavoidably slightly different from the master located XTAL oscillator, due to the finite precision of the two crystals. However the difference between two frequencies is so small that the half slave located XTAL oscillator frequency may easily be locked to the master with the proper phase lock loop. The moment the coherent link is interrupted, the master carrier frequency and phase are ty not present any more, so that the user located XTAL oscillator is ty unlocked but, due to its inherent stability, may hold its frequency stable and very close to the previously locking master frequency. The possible small frequency difference is typically not an issue at all because the link with the master is not active. The former user half slave is now a half master that may act as a new independent local master toward any other network element.

A suitable method whereby the network may be activated may be characterized by some or all of the following:

1. The access point is the network-reference "full master".

2. Repeaters and users are "half slaves".

3. The access point may be located on the ceiling where the repeaters are, and may employ a "V" shape used for the propagation directions.

4. At the time when the network starts up, at least one user may be present to act as a preliminary repeater toward the ceiling-located repeaters, and may employ a "V" shape for the propagation directions.

5. The access point connects the user and locks it, turning it into a "half master".

6. The "half master" user connects the closest "half slave" repeater on the ceiling and locks it, turning it in to a new "half master".

7. Some or all the transceivers of the network, repeaters and users, may be turned into "half masters", potentially able to act as local masters toward any network element.

8. Some or all network elements may be contemporarily coherently locked to the master carrier frequency and phase; e.g. using a cascaded locking of all the network elements.

If an individual user moves the position of his transceiver, the phase of the user local oscillator may change from the requested 90 degrees, but the phase lock loop may restore to 90 degrees as usual. The frequency has no predictable reason to change significantly. However if for any reason the frequency of the "half master" changes, the phase-frequency loop circuit may restore frequency and phase as appropriate.

Interoperability with MIMO transceivers is now described.

1. MIMO transceivers may operate toward BN users ONLY through a BN access point, at frequency fl set by the proper standard rules for interoperability. 2. AESA access point may re-transmit toward AESA users the MIMO signal using a different carrier frequency f2, in order to avoid reciprocal interference with MIMO signals.

3. From that point on, AESA network may behave as described above.

Fig. 1 illustrates a wireless network using 60 GHz AESA transceivers. Every computer on the desks has a dedicated transceiver. Repeaters are installed on the ceiling of the indoor environment. Every user may establish a radio link with any other user through the first available repeater. Additional repeaters may be installed on the upper border of the separating walls of the indoor environment.

Fig. 2 shows a laptop with open cover, with retractable tablets on the upper part. On the upper face of the tablets the Rx and TX antennas of the transceiver are assembled. The distance between the antennae may be large enough to avoid a parasitic link between them. The antennas may have their radiating face turned toward the upper side of the indoor environment.

The tablets carrying the RX and TX antennas are ty retractable inside the cover of the laptop. The tablets may always be positioned parallel to the ceiling of the indoor environment. The tablets may be set manually, mechanically and consistently with the position of the laptop cover, or with electro mechanic devices performing the same function.

The antennae of the laptop transceiver may be connected to the related electronic circuits through a strip-line conductor carried by a flexible laminate.

Fig. 3 illustrates a transceiver which is operational when the cover is closed. This circumstance may for example occur if a user prefers to use his laptop through a docking station.

Fig. 4 illustrates a wireless network using 60 GHz AESA transceivers. Every computer on the desks has a dedicated transceiver. Access point and repeater equipment may be installed on the ceiling of the indoor environment. Every user may establish a radio link with any other user e.g. through the first available repeater. As illustrated, some or all of the following, suitably arranged e.g. as shown, may be included in the apparatus:

1100: Indoor network scenario.

1101: Signal coming from outside the network. 1102: Signal going outside the network. 1103: Access point transceiver. 1104 : Repeater transceiver. 1105: Signal from user to repeater. 1106: Signal from repeater to user. 1107: User's transceiver. 1108: User' s transceiver. 1109: Signal from repeater to user. 1110: Signal from user to repeater. 1111 : User's computer. 1112: User's computer.

Fig. 5 illustrates the receiver subsystem, which may comprise a common part to access point, repeater and user transceivers. The subsystem may include some or all of the following, suitably arranged e.g. as illustrated:

1200: Common receiver to access point and users.

1201: Subsystem for RX beam steering.

1202: Reference signal @15 GHz from block 1403.

1203: PSIPPO 15 30 GHz.

1204: Buffer amplifier @ 30 GHz.

1205: 30 GHz power divider.

1206: Array of 30 GHz buffer amplifiers.

1207: Array of 30 60 GHz PSIPPO.

1208: Array of 60 GHz buffer amplifiers.

1209: Array of direct down converters with phase detector.

1210: Array of 60 GHz buffer amplifiers. 1211 : Array of low noise R/X front ends. 1212: Array of radiators.

1213: Output of coherently down converted signals.

1214: Manifold collecting the coherent down converted signals.

1215: Error phase setting the carrier frequency.

1216: Error phase setting 90 degrees carrier phase.

1217: Loop amplifier.

Fig. 6 illustrates a transmitter subsystem, which may comprise a common part to access point, repeater and user transceivers. The subsystem may include some or all of the following, suitably arranged e.g. as illustrated:

1300: Common transmitter to access point and users.

1301 : Subsystem for TX beam steering.

1302: Reference signal @15 GHz from block 1403.

1303: PSIPPO 15 30 GHz.

1304: Buffer amplifier @ 30 GHz.

1305: 30 GHz power divider.

1306: Array of 30 GHz buffer amplifiers.

1307: Array of 30 60 GHz PSIPPO.

1308: Array of 60 GHz buffer amplifiers.

1309: Array of direct up converters.

1310: Array of 60 GHz buffer amplifiers.

131 1 : Array of low noise T/X front ends.

1312: Array of radiators.

1313: Input of baseband signal to the mixers. Fig. 7 illustrates an access point system typically including some or all of a T/X, R/X, 15 GHz reference signal generator, input baseband subsystem and output baseband subsystem. Depending on the mode, the user transceiver behavior may act as half master or half slave. The access point always acts as master and is the reference item all the network elements are locked to. The apparatus of Fig. 7 may include some or all of the following, suitably arranged e.g. as illustrated:

1400: Transceiver for Access point and users.

1200: Receiver.

1300: Transmitter.

1401: Reference XTAL oscillator.

1402: Controlled 15 GHz VCO.

1403: Buffer amplifier.

1404: Digital baseband subsystem.

1405: Buffer amplifier.

1406: Digital baseband subsystem.

1407: Input baseband signal.

Fig. 8 illustrates a repeater system including some or all of: T/X, R/X and 15 GHz reference signal generator. Baseband subsystems are ty not present: the received down converted signal, after amplification, is up converted and retransmitted. Depending on the mode behavior the repeater system may act as half master or half slave. The system may include some or all of the following, suitably arranged e.g. as illustrated:

1500: Transceiver for Access point and users.

1200: Receiver.

1300: Transmitter.

1402: Reference XTAL oscillator.

1403: Controlled 15 GHz VCO. 1501: Baseband buffer amplifier. 1502: Loop amplifier.

According to certain embodiments, software network management functionality is provided e.g. for the event that 2 Tx-Rx pairs simultaneously communicate via the network.

A wireless area network compliant system using a phase array antenna is now described, which may be useful in conjunction with the systems of Figs. 1 - 8 and which may for example be constructed and operative in accordance with the teachings of US Patent 7,852,265 to Milano and Weinstein. The following embodiments thereof may be useful in conjunction with the systems of Figs. 1 - 8:

1. A wireless area network communication system comprising: at least one phased array antenna frame, a phased array antenna circuit connected to the at least one phased array antenna frame wherein said phased array circuit and said at least one phased array antenna frame are adapted to transmit and receive wireless area network compliant signals from or to wireless area network devices; and wherein said phased array antenna circuit comprises a plurality of phased shifted locked injected push-push oscillator (PSIPPO).

2. System 1 wherein the at least one phased array antenna frame transmits or receives radiation.

3. System 1 wherein the phased array antenna circuit is for driving and controlling said at least one phased array antenna frame.

4. System 1 wherein the wireless area network is a wireless personal area network.

5. System 1, wherein said at least one phased array antenna frame comprises at least two groups of radiators.

6. System 5 wherein one of said at least two groups of radiators is defined as a reference group.

7. The system of claim 6 wherein one of said at least two groups of radiators is controlled by said phased array circuit to transmit or receive with a phase shift relative to said reference group. 8. The system of claim 7 wherein the phase shift is programmable or hard coded.

9. System 1, wherein said at least one phased array antenna frame comprises at least two substantially linear one dimensional arrays of radiators.

10. System 1, wherein said at least one phased array antenna frame comprises an even number of substantially linear one-dimensional arrays of radiators, wherein each substantially linear one-dimensional array of radiators includes two power of N radiators, where N is an integer greater than 1.

11. System 1, wherein said at least one phased array antenna frame includes radiators that are substantially hexagonal in shape.

12. System 5, wherein the system is selectively switching between different radiation modes associated with each group of radiators.

13. System 12, wherein a radiation mode is defined according to the number of groups of radiators that transmit and receive in different phase shift and according to said programmable phase shift.

14. System 1, wherein said phased array circuit controls said phased array antenna frame to radiate in a horizontal beam aperture.

15. System 14, wherein the horizontal beam aperture width is substantially from 3 to substantially 15 degrees.

16. System 1, wherein the system is adapted to communicate with multiple wireless area network devices.

17. System 1, wherein the system is adapted to communicate with Personal Computers.

18. System 1, wherein the system is adapted to communicate with at least one TV device.

19. System 8, wherein said programmable phase shift is +/-180 degrees. 20. System 8, wherein said programmable phase shift is +/-180 degrees and wherein said programmable phase shift is created by using transmission lines for inversing the signal phase.

21. System 1, wherein wireless area network compliant signals are transmitted in the about 57 to about 64 GHz band.

22. System 12, wherein the system is selectively switching between two radiation modes.

23. System 12, wherein the system is selectively switching between two radiation modes and wherein said at least one phased array antenna frame comprises two linear one-dimensional arrays of radiators.

24. System 12, wherein said selectively switching between different radiation modes depends on the level of signals that arc received in said different phase modes.

25. System 14, wherein said horizontal beam aperture is steered horizontally according to a programmable pattern.

26. System 1, wherein transmitting and receiving wireless area network compliant signals from or to wireless area network devices is optionally performed through building walls.

27. System 5, wherein the phased array antenna circuit comprises: a. an oscillator circuit for providing a reference signal, b. at least two levels of phase shifted locked injected push-push oscillators for steering a beam that is created by the phased array antenna frame; c. up converters for up converting a signal that is transmitted by the phased array antenna and down converters for down converting a signal that is received by the phased array antenna; and d. transmission lines for selectively providing a phase shift to a reference signal that is provided to said up or down converters.

28. A method for phased array antenna wireless communication, comprising the steps of providing at least one phased array antenna frame and phased array antenna circuit connected to the at least one phased array antenna frame; and controlling said at least one phased array antenna frame by said phased array antenna circuit to transmit and receive wireless personal area network compliant signals from or to wireless area network devices, wherein said phased array antenna circuit comprises a plurality of phased shifted locked injected push-push oscillator (PSIPPO).

29. A circuit for driving a phased array antenna wireless communication system comprising: a. an oscillator circuit for providing a reference signal, b. at least two levels of phase shifted locked injected push-push oscillators (PSIPPO) for steering a beam that is created by the phased array antenna frame; c. up converters for up converting a signal that is transmitted by the phased array antenna and down converters for down converting a signal that is received by the phased array antenna; and d. transmission lines for selectively providing a phase shift to a reference signal that is provided to said up or down converters.

30. The circuit for driving a phased array antenna wireless communication system e.g. as per system 29 above, wherein at least one of the at least two levels of phase shifted locked injected push-push oscillators is used for steering a beam that is created by the phased array antenna frame horizontally, and at least one of the at least two levels of phase shifted locked injected push-push oscillators is used for steering a beam that is created by the phased array antenna frame vertically.

As the amount of home and office wireless accessories is rapidly increasing, there is an increasing demand for broadband wireless access solutions.

As an example, a standard that has been defined to regulate this communication domain is the IEEE 802.15 which is divided to five sub groups 802.15.1-802.15.5. Among these standards, 802.15.3 which deals with High Rate WPAN (Wireless Personal Area Network) is very important for mainly indoor wireless communication.

The IEEE 802.15.3 Task Group 3c (TG3c) was formed in March 2005. TG3c is developing a millimeter-wave-based alternative physical layer (PHY) for the existing 802.15.3 Wireless Personal Area Network (WPAN) Standard 802.15.3-2003.

This mm- Wave WPAN will operate in the new and clear band including 57-64 GHz unlicensed band defined by FCC 47 CFR 15.255. The millimeter-wave WPAN will allow high coexistence (close physical spacing) with all other microwave systems in the 802.15 family of WPANs. In addition, the millimeter-wave WPAN will allow very high data rate over 1 Gbit/s applications such as high speed internet access, streaming content download (video on demand, HDTV, home theater, etc.), real time streaming and wireless data bus for cable replacement. Optional data rates in excess of 3 Gbit/s will be provided.

The need to implement communication system in this frequency range, with such broadband capabilities and at the same time to comply with a commercial requirement of low-cost imposes severe technical difficulties.

One of the candidates to implement this communication domain is MIMO (multiple input multiple output). However for several reasons, (as simulations calculations and mechanical considerations), MIMO is considered not suitable for the foregoing requirements.

There is a need for an innovative technology in order to provide a cost effective system that will be able to fulfill the requirements of high frequency, high bandwidth and low cost. The technical system performance recognized as indispensable for the mentioned achievements is the improvement of the antenna beam focus, together with the ability of wide beam steering of the antenna. A possible solution is the use of phased arrays antenna system.

A method and system for implementing a WPAN by phased array antenna devices is described herein.

There is provided a wireless area network communication system comprising at least one phased array antenna frame, a phased array antenna circuit connected to the at least one phased array antenna frame wherein the phased array circuit and said at least one phased array antenna frame are adapted to transmit and receive wireless area network compliant signals from or to wireless area network devices.

In some exemplary embodiments of the system the phased array antenna frame transmits or receives radiation. In some exemplary embodiments of the system the phased array antenna circuit serves for driving and controlling said at least one phased array antenna frame.

In some exemplary embodiments of the system the wireless area network is a wireless personal area network. In some exemplary embodiments of the system the phased array antenna frame comprises at least two groups of radiators wherein one of the groups of radiators is defined as a reference group.

In some exemplary embodiments of the system one of the groups of radiators is controlled by said phased array circuit to transmit or receive with a phase shift relative to said reference group. In some exemplary embodiments of the system the phase shift is programmable or hard coded. In some exemplary embodiments of the system phased array antenna frame comprises at least two substantially linear one dimensional arrays of radiators. In some exemplary embodiments of the system the phased array antenna frame comprises an even number of substantially linear one-dimensional arrays of radiators, wherein each substantially linear one- dimensional array of radiators comprises two power of N radiators, where N is an integer greater than 1.

In some exemplary embodiments of the system the phased array antenna frame includes radiators that are substantially hexagonal in shape. In some exemplary embodiments of the system the system is selectively switching between different radiation modes associated with each group of radiators. In some exemplary embodiments of the system a radiation mode is defined according to the number of groups of radiators that transmit and receive in different phase shift and according to said programmable phase shift. In some exemplary embodiments of the system the phased array circuit controls said phased array antenna frame to radiate in a horizontal beam aperture. In some exemplary embodiments of the system the horizontal beam aperture width is substantially from 3 to substantially 15 degrees. In some exemplary embodiments of the system the system is adapted to communicate with multiple wireless area network devices. In some exemplary embodiments of the system the system is adapted to communicate with Personal Computers.

In some exemplary embodiments of the system the system is adapted to communicate with at least one TV device. In some exemplary embodiments of the system the programmable phase shift is +/-180 degrees. In some exemplary embodiments of the system the programmable phase shift is +/-180 degrees and the programmable phase shift is created by using transmission lines for inversing the signal phase. In some exemplary embodiments of the system the wireless area network compliant signals are transmitted in the about 57 to about 64

GHz band. In some exemplary embodiments of the system the system is selectively switching between two radiation modes. In some exemplary embodiments of the system the system is selectively switching between two radiation modes and wherein the phased array antenna frame comprises two linear one-dimensional arrays of radiators.

In some exemplary embodiments of the system the system is selectively switching between different radiation modes according to the level of signals that are received in said different phase modes. In some exemplary embodiments of the system the horizontal beam aperture is steered horizontally according to a programmable pattern. In some exemplary embodiments of the system the transmitting and receiving wireless area network compliant signals from or to wireless area network devices is optionally performed through building walls. In accordance with a preferred embodiment of the present method, there is provided a method for implementing a wireless communication comprising the steps of providing at least one phased array antenna frame and phased array antenna circuit connected to the at least one phased array antenna frame; and controlling said at least one phased array antenna frame by said phased array antenna circuit to transmit and receive wireless personal area network compliant signals from or to wireless area network devices.

There may be provided a room with two fixed phased array antenna systems and two PCs with phased array antenna system according to an exemplary embodiment of the invention.

There may be provided a room with one fixed phased array antenna system and several PCs with phased array antenna system according to an exemplary embodiment of the invention.

There may be provided a room with two fixed phased array antenna frames and two PCs with phased array antenna system, in a first radiation mode, according to an exemplary embodiment of the invention.

There may be provided a room with two fixed phased array antenna frames and two PCs and a TV with phased array antenna systems, in a second radiation mode, according to an exemplary embodiment of the invention.

Signal distribution may be provided among the rooms on a same floor, according to an exemplary embodiment of the invention.

There may be provided a phased array antenna frame according to an exemplary embodiment of the invention.

There may be provided a phased array antenna frame that is composed of separate units for receiving and transmitting, according to an exemplary embodiment of the invention.

There may be provided a suitable radiation pattern of a phased array antenna frame in a first mode of operation according to an exemplary embodiment of the invention.

There may be provided a suitable radiation pattern of a phased array antenna frame in a second mode of operation according to an exemplary embodiment of the invention.

There may be provided a circuit for implementing a phased array antenna circuit that supports a combination of two modes of operation according to an exemplary embodiment of the invention.

Published PCT applications PCT/IL2006/001144 filed on Oct. 3, 2006 and in PCT/IL2006/001039 filed on Sep. 6, 2006 describe elements and circuit designs for providing low cost and light weight distributed T/R multi-module for active phased array antennas. The circuits described in these publications can be implemented as low cost and small sized circuits or manufactured as integrated chips to generate and control the signals transmitted and detected by phase array antennas. Any or all of the teachings of these publications may be employed to provide suitable phase array antennas for implementing the current invention as further described below.

There is provided a phased array antenna system deployment 3100A. This may include a living room 3101 where two PCs 3130, 3140 are located at different sections of the room. Each PC is equipped with one phased array antenna system 3117, 3122, respectively. Each phased array antenna system includes a phased array antenna frame 3115, 3120 respectively, and a phased array antenna control and driving circuit 3116 and 3121 respectively (hereinafter "phased array antenna circuit").

In an exemplary embodiment of the invention there are two fixed phased array antenna systems 3107, 3112, located at different corners of the room. Each of the systems 3107 and 112 also includes a phased array antenna frame 3105, 3110 respectively, and a phased array antenna circuit 3106 and 3111 respectively.

Each of the phased array antenna frames is transmitting and/or receiving data. 3150, 3160, 3155 and 3165 are radiation patterns of the phased array antenna frames 3105, 3115, 3110 and 3120 respectively.

In an exemplary embodiment of the invention a phased array antenna system 3107 is steering its beam 3150 horizontally (azimuth steering) until it reaches an optimal reception level from the phased array antenna system 3117. The same procedure also applies for the phased array antenna system 3117 which performs a horizontal steering of its beam 3160 until acquiring an optimal reception level from the phased array antenna system 3107.

The same procedure applies also to the phased array antenna systems 3112 and 3122.

The narrow horizontal beam aperture and the low side lobes of a phased array antenna system according to the invention guarantee the ability to avoid the event of locking on side lobes.

Optionally, once an optimal level of signal reception is reached, the phased array antenna system memorizes the azimuth for enabling a quick initialization at later power-on events.

Using only two systems the entire area of a rectangular room can be covered.

In another exemplary embodiment of the invention a single phased array antenna system 3107 is communicating with Three phased array antenna systems 3117, 3122 and 3172 the phased array antenna systems 3117 and 3122 are connected to a PC device 3130 and 3140 respectively and the phased array antenna system 3172 is connected to a TV device 3169.

The ability of the systems to interact independently is obtained by beam steering of all the antennas as will be further described. In order to transmit and receive data from multiple phased array systems, the phased array system 3107 performs an azimuthally steering and electronically rotates between three positions indicated by the ellipse 3150 that points to the PC 130, the ellipse 3152 that points to the PC 3140 and ellipse 3153 that points to TV 3169. After the locking transient between the fixed system and the PC/TV/cell phone etc, the communication with the PC devices is typically bidirectional, while the communication with the TV may be unidirectional, where the TV phased array antenna system may only receive data.

The antenna steering by a phased array antenna system is extremely fast, typical duration of switching from a first beam direction 3150 to a second beam direction 3152 or 3153 is in the order of magnitude of micro seconds.

A single phased array antenna system is able to communicate simultaneously with a multiple of WPAN devices on a time sharing base, where the limit on the number of devices is dictated by the bandwidth requirements of the devices and the bandwidth capability of the phased array antenna system. While a phased array antenna system 107 may be communicating with three phased array antenna systems 3117 and 3122 it is possible that the phased array antenna system 107 will also communicate with any WPAN compliant device other than phased array antenna system.

Regarding the phased array antenna beam, in a first mode of radiating there is one main lobe of radiating e.g. 3150, 3155, 3160 and 3165, the lobe has an aperture of around 30 degree in the vertical plan, which should provide good coverage when there is a clear line of sight between two communicating devices. However in a dynamic environment, when obstacles, e.g. a person moving across the room, may obscure the line of sight between communicating devices, another approach may be employed.

Regarding the same room 3101 when a person 3180 breaks the line of sight between the two phased array antenna systems 3112 and 3122, when the system detects deterioration of signal level reception it switches to a second mode of radiation, where each of the single main lobes 3165 and 3155 splits to two main lobes, i.e. 3155 splits into 3155 A and 3155B, and 3165 splits into 3165 A and 3165B. The two main lobes that are radiated by the phased array antenna frame are intended to transmit and receive radiation by indirect path, namely to enable transmission and reception of electromagnetic echo from the environment, mainly from surrounding walls, e.g. the path indicated by the broken line marked with numeral 170.

Regarding a signal distribution among nine rooms 3193 on the same floor 3100E:

In the input bound the signal is intercepted by an antenna 3190 and received by a master phased array antenna 3191. The signal is transmitted and received by the set of phased array antennas 3192a-3192r. The signal is transmitted and received across room walls, for example when transmitted from the phased array antenna 3192b to 3192e while crossing the wall 3194. The relative low attenuation of high frequency radiation provides the ability to cross common room walls such as concrete, plywood, clay brick, glass and the like. For example, the attenuation of a 5.8 GHz signal caused by a typical concrete wall is about 7 dB. Thus, a single master and a set of phased array antennas can provide full wireless coverage for an entire door. The output bound is symmetric but on the opposite direction.

The phased array antennas 3192a-3192r are adapted to serve also as repeaters in order to compensate on the attenuation of the signal along its path, while the technique of signal distribution by a set of repeaters is known in the art its detailed description is omitted.

A radiating part of a distributed active phased array antenna (APAA) (referred to as "phased array antenna frame") 3200A is described, that includes two one-dimensional arrays of micro- strip radiators (referred to as "radiators") 3210, 3215 located on a rectangular casing 205, including a dielectric substrate with the related base plate. The one-dimensional arrays of radiators comprise 8 radiators marked as Al to A4, Bl to B4. Each radiator is shaped as a hexagonal patch, for example radiator Al, 3230. Each radiator has a feeder (an I/O port that conveys the electromagnetic wave to and from the radiator) 3235, 3245 either at the upper vertex of the radiator (Al to A4), or at the lower vertex of the radiator (e.g. Bl to B4). The hexagonal shape of the radiator has been shown by simulation to provide better results than a square radiator or a circular radiator, in terms of transmission gain and/or receiving gain and also by providing better isolation between adjacent radiators, for the same distance between them.

In an exemplary embodiment of the present invention, the positioning of the radiator's feeder forms a symmetric structure. In the first one-dimensional array of radiators the radiator's feeders are located at the upper vertex of the hexagonal patch, while at the second one- dimensional array of radiators the radiator's feeders are located at the lower vertex of the patch. It should be noted that this symmetric positioning of the radiator's feeder optionally contributes to improving the symmetry of the radiation pattern.

The antenna dimensions depend on the wave's frequency and the dielectric constant of the substrate. As an example, a WPAN radiator at 60 GHz, implemented on substrate with dielectric constant 6, has dimensions in the order of magnitude of about one millimeter. This compact embodiment enables the inclusion of the phased array antenna described in this invention in various hand-held devices such as palm-computers, Personal data Organizers (Blackberry), Cellular Phones, notebook computers, etc.

In an exemplary embodiment of the invention, to achieve wider coverage angle with still high power density for communicating with the device described above, different radiation patterns (referred to as "radiation modes") arc generated with the same physical array of radiators.

Optionally, production of the multiple radiation modes by antenna 3200 is defined by the relative phase shift to a signal among the two one-dimensional arrays of radiators 3210, 3215.

In an exemplary embodiment of the present invention, a first radiation mode is defined by providing the requested phases to the two one-dimensional arrays of radiators 3210 and 3215, in such a way that there is no phase difference between every element "A" of the first one- dimensional array and the correspondent element "B" of the second one-dimensional array. A second radiation mode is defined by providing the requested phases to the two one-dimensional arrays of radiators 3210 and 3215, in such a way that there is phase difference of 180 degrees between every element "A" of the first one-dimensional array and the correspondent element "B" of the second one-dimensional array.

It is possible to both transmit and receive via the same radiators and it is sometimes more efficient architecture. However in an exemplary embodiment of the invention, the transmission and receiving is split between transmitting radiators and receiving radiators. Deployment of different radiators for transmission and receiving may be carried out in various topologies, such as separating the functions to two different phased array frames or alternatively define sub groups of the radiators in a phased array frame for transmission while the complementary sub group is used for receiving.

In order to create the two radiation modes as mentioned above and when using the phased array antenna control and driving circuit as will be further described, the phased array antenna frame should be positioned horizontally.

A phased array antenna transceiver may be provided where transmission and receiving is conducted by two separate units according to an exemplary embodiment of the invention. As will be further described, separation of the receiving unit and the transmitting unit is expected to provide technical and economical advantages when the radiating frequency is relatively high.

The receiving and transmitting units have basically the same structure. The transmitting unit e.g. on the left side may have transmitting radiators A1T-A4T and B1T-B4T. The receiving radiators are shown on the right side, e.g. , may be termed A1R-A4R and B1R-B4R. The feeders of the transmitting unit are marked 3261a-3264a and3261b-3264b, and the feeders of the receiving unit may be termed 3265a-3268a and 3265b-3268b.

A connection between silicon chips 3270-3279 that contain the electronic circuits that provide the antenna control (referred to as phased array circuit), may be provided.

Micro strip lines 3261a-3268a 3261b-2368b of defined length are the feed of the radiators, and lays on the upper surface of a dielectric substrate (not shown). The hexagonal patches are laying on the upper surface of a second substrate (not shown), overlapping the previous one, such that there will be an efficient electro magnetic transfer of energy from the feeds to the patches.

In the transmitting unit, the feeders 3261a-3264a and 3261b-3264b serve for transferring the carrier generated and handled by the circuits 3270-3274 to the radiators A1T-A4T B1T-B4T, while in the receiving unit the signal, received through the radiators A1R-A4R, B1R-B4R, will be down converted to base band by the signal generated and handled by the circuits 3275-3279.

The circuits defined as 3270-3274 and 3265-3279 are described in detail in the applications referred to above. A radiation pattern is created by the first radiation mode. The radiation pattern 3310 has a vertical aperture of about 30 degree 3312, which is wide enough to cover static devices that may reside in a typical room either at home or in an office at the height of a standard table. The beam is intended not to be steered in elevation.

A radiation pattern 3320 is created by the first radiation mode. The radiation pattern has a horizontal aperture of about 5 degree 3325. A narrow horizontal beam aperture enables to concentrate the power in a narrow angle, with low side lobes level. The beam is intended to be steered in azimuth, so that the section is intended to sweep a wide azimuth angle.

A radiation pattern is created by the second radiation mode. The radiation pattern has two main lobes 3330 A and 3330B. In an exemplary embodiment of the invention the second mode of radiation radiates the same amount of power of the first mode, but the gain of each lobe is half the gain of the first mode. However this mode results with wide spread distribution of the radiated data (as well as wide angles for reception of data), to enable indirect communication. The two main lobes created at the second mode of radiation are targeted to both the floor and the ceiling, and part of the radiation is reflected from the ceiling and floor (as well as from other objects in the room) reaches the target antenna.

The beam is intended not to be steered in elevation.

A radiation pattern is created by the second radiation mode. However in the horizontal plan, the radiation patterns of the first and second mode of radiation have the same aperture.

The beam is intended to be steered in azimuth, so that the section is intended to sweep a wide azimuth angle.

The first mode of radiation is generated when the signals at the radiators A1-A4 and corresponding B1-B4 have phase difference of 0 degrees.

The second mode of radiation is generated when the signals at the radiators A1-A4 and corresponding B1-B4 have phase difference of 180 degrees.

A base of a circuit may provide the carrier signals to an array of radiators, according to an exemplary embodiment of the invention.

While at relatively low frequencies it is commercially more effective to use the same antenna for both receiving (R/X) unit and transmitting (T/X) unit, at the higher frequencies like the 60 GHz the circuitry connected to this function involve semiconductor real estate not compatible with the small size of the array of radiators, so that it will be preferable to separate the T/X and R/X functions in two different subsystems. As will be further described, the differences between the physical structure of the transmitting unit and a receiving unit are minor, as long as the only different functions are the UP-converter for the T/X 3491i-3491p, and the DOWN- converter for the R/X. 3491a-3491h. They are basically the same circuit, but used in different ways. The UP-converter is located at the input of the T/X power amplifier, while the DOWN- converter is located at the output of the R/X low noise amplifier.

The circuit uses an oscillator unit 3405 whose output is provided to two splitting units 3409, 3410. The power divider 3409 provides the reference signal to the R/X unit while the power divider 410 provides the reference signal to the T/X unit. The following description will mainly refer to the R/X unit-expanding the description to the T/X unit only where there are substantial differences. The signals then arrive to a first level of PSIPPO (phase shift push-push oscillator) 3420-3421. The phase shift that is determined at this level of PSIPPO serves to steer the beam.

The signal then passes through another level of splitting elements 3430-3431 (power splitters) and proceeds to a second level of PSIPPO 3435a-3435d. Persons skilled in the art will readily appreciate that the phase shift that is determined at this level of PSIPPO contributes in steering the beam. Applying a zero degree phase shift at the first 3420, 3421, and second level 3435a- 3435d of PSIPPO results in a substantially vertical beam, where its symmetry axis is perpendicular to the antenna surface.

At the next stage the signals are delivered to four power splitters 3440-3443 and then proceed to the multi-function blocks 3450-3453. As long as the mentioned blocks have the same structure, only one phase shift unit 3450 is described.

A block 3450 typically includes two branches, each one connected to radiators 3495a & 3495b.

The radiators are denoted Al & Bl. The branch 3284a delivers the carrier signal to the connected mixer with a certain phase. The second branch, 3480a-3482a, delivers the same signal to the connected mixer with a phase equal to branch 3484a, or shifted by 180 degrees, depending on the position of the switches 3480a & 3482a. This way the array of radiators will be able to generate the two radiation modes described above. Optionally the transmission line 3481a applies a phase shift that is greater or smaller than 180 degrees. The down converter mixers 3491a, 3491b get signals that were received in the antenna patch 3495a, 3495b respectively and were amplified by the low noise amplifiers 3492a, 3492b respectively and produce the incoming signal 3490a, 3490b respectively.

The T/X path differs from the R/X path in that the mixers are up converter mixers 3491i-3491p that receive the data signals 3490i-3490p and produce an outgoing signal that goes to the antenna patches 3495i-3495p after being amplified by the amplifiers 3495i-3495p.

The phase difference between the two branches can be accomplished, in principle, by inserting an additional level of PSIPPO before each mixer. This solution may require a higher number of components.

Delay elements 3481a-3481h are simple and low cost transmission lines, as are the electronic switches 3480a-3480h 3482a-3482h. The usage of electronic switches and delay elements reduces both cost and size, compared to the solution with an additional level of PSIPPO.

In another exemplary embodiment the path from the splitter 3440 to the down converter mixer 490a (and all the equivalent paths) also includes an optional phase shift path, enabling the circuit to be programmed for more phase shift combinations.

In some embodiments of the invention, the WPAN phased array antenna system will switch between more than two radiation modes, using an equal or different number of linear arrays of radiators.

In some embodiments of the invention, the WPAN phased array antenna system may provide a phase shift that is greater or smaller than 180 degrees to the one-dimensional arrays of radiators.

In some embodiments of the invention, the WPAN phased array antenna system may include more or less than two one linear arrays of radiators. In some embodiments of the invention, the WPAN phased array antenna system may include various combinations of radiators other than linear arrays of radiators, where any sub-group of the radiators will be associated with a programmable phase shift with reference to any reference sub-group.

In some embodiments of the invention, the WPAN phased array antenna system may include radiation modes where the azimuth angle beam is narrower or wider than the one that was described in the foregoing description.

In some embodiments of the invention, the WPAN phased array antenna system may include radiation modes where the vertical beam aperture is narrower or wider than the one that was described in the foregoing description, and where the vertical beam distribution is different from forms described herein.

In some embodiments of the invention, the WPAN phased array antenna system may perform a periodical horizontal antenna steering to search for transmitting devices that may be communicated by the system.

While operating the WPAN phased array antenna system according to an exemplary embodiment of the invention, the system switches among the two radiation modes. The switching may be a periodic switching pattern or any desired pattern. In an exemplary embodiment of the invention, the system is able to alter the switching pattern to accommodate dynamic situations, for example when receiving or transmitting sources join or leave the area that is covered by the system, or when different needs and priorities are required. Optionally, alteration of the switching pattern provides priority in coverage of one area over another, for example to increase the bandwidth to a specific client device.

The use of radiation modes where the phase shift between the one-dimensional arrays of radiators is either zero degrees or 180 degrees enables to simplify the electronic circuits that support the transmission and receiving in the WPAN compliant phased array system.

The above described methods and systems may be varied in many ways, including omitting or adding steps, changing the order of steps and the type of devices used. It should be appreciated that different features may be combined in different ways. Apparatus for radar imaging based on injected push-push oscillators is now described, which may be useful in conjunction with the systems of Figs. 1 - 8 and which may for example be constructed and operative in accordance with the teachings of United States Patent 7800453 to Alberto Milano. The apparatus may relate to radar imaging and to phased array antennas. The apparatus may also relate to transmitter/receiver modules, push-push oscillators and Injection locked push-push oscillators for phased array antennas.

The following embodiments of the Apparatus for radar imaging based on injected push-push oscillators may be useful in conjunction with the systems of Figs. 1 - 8:

1. A reference signal generator comprising: a quartz oscillator; and at least one level of phase shifted injection locked push-push oscillators cascaded with the quartz oscillator; wherein said phase shifted injection locked push push oscillators comprise one or more push push oscillators and are adapted to receive an injected signal of a specific frequency and phase, and produce a signal with a frequency that is an even integer multiple of the input frequency and with a phase shift relative to the injected signal.

2. Reference signal generator 1 wherein the reference signal generator comprises only two levels of phase shifted injection locked push-push oscillators.

3. Reference signal generator 1 wherein the reference signal generator comprises at least first and second levels of phase shifted injection locked push-push oscillators.

4. Reference signal generator 3 wherein at least one individual level of push-push oscillators comprises more than one phase shifted injection locked push-push oscillator.

5. Reference signal generator 1, further comprising multiple phase shifted injection locked push-push oscillators forming a tree structure.

6. A transmitter/receiver module comprising: at least one level of phase shifted injection locked push-push oscillators; and a receiving functionality receiving a sampled portion of power subsequently radiated by the transmitter/receiver with phase shifted injection locked push-push oscillators; wherein said phase shifted injection locked push push oscillators comprise one or more push push oscillators and are adapted to receive an injected signal of a specific frequency and phase, and produce a signal with a frequency that is an even integer multiple of the input frequency and with a phase shift relative to the injected signal.

7. Transmitter/receiver module 6 wherein said transmitter/receiver module comprises a plurality of levels of phase shifted injection locked push-push oscillators.

8. Transmitter/receiver module 6 wherein said receiving functionality comprises a direct balanced down converter.

9. Transmitter/receiver module 6 further comprising multiple phase shifted injection locked push-push oscillators forming a tree structure.

10. Radar imaging apparatus comprising: a reference signal generator according to claim 1; a phased array antenna including at least one transmitter/receiver module with phase shifted injection locked push-push oscillators; and additional apparatus cascaded with the reference signal generator and with at least one transmitter/receiver module to generate a radar image.

11. Imaging radar apparatus 10 wherein said transmitter receiver module comprises at least one level of phase shifted injection locked push-push oscillators.

12. Imaging radar apparatus comprising: a reference signal generator; at least one transmitter/receiver module 6; and additional apparatus cascaded with the reference signal generator and with at least one transmitter/receiver module to generate a radar image.

13. A method for generating a reference signal for radar imaging, the method comprising: cascading a quartz oscillator with at least one level of phase shifted injection locked push-push oscillators wherein said phase shifted injection locked push push oscillators comprise one or more push push oscillators and are adapted to receive an injected signal of a specific frequency and phase, and produce a signal with a frequency that is an even integer multiple of the input frequency and with a phase shift relative to the injected signal.

14. Method 13 wherein said quartz oscillator is cascaded with a plurality of levels of phase shifted injection locked push-push oscillators.

15. Method 13 wherein said at least one level of phase shifted injection locked push-push oscillators comprises only two levels of phase shifted injection locked push-push oscillators.

16. Method 13 wherein at least one individual level of phase shifted injection locked push-push oscillators comprises more than one phase shifted injection locked push-push oscillators.

17. A method for generating a radar transmitter/receiver module of a phased array antenna comprising: providing at least one level of phase shifted injection locked push-push oscillators and a receiving functionality receiving a sampled portion of power subsequently radiated by the phase shifted injection locked push-push oscillators; and wherein said phase shifted injection locked push push oscillators comprise one or more push push oscillators and are adapted to receive an injected signal of a specific frequency and phase, and produce a signal with a frequency that is an even integer multiple of the input frequency and with a phase shift relative to the injected signal.

18. Method 17 and further comprising cascading a reference signal generator and additional apparatus with said at least one level of phase shifted injection locked push-push oscillators to generate a radar image.

19. A radar imaging method comprising cascading a reference signal generator comprising at least one level of phase shifted injection locked push-push oscillators, a phased array antenna comprising at least one transmitter/receiver module, and additional apparatus to generate a radar image; and wherein said phase shifted injection locked push push oscillators comprise one or more push push oscillators and are adapted to receive an injected signal of a specific frequency and phase, and produce a signal with a frequency that is an even integer multiple of the input frequency and with a phase shift relative to the injected signal.

20. Method 19 wherein said transmitter receiver module comprises at least one level of phase shifted injection locked push-push oscillators.

21. Method 19, further comprising: at least first and second levels of phase shifted injection locked push-push oscillators.

22. Method 19, further comprising: using a cascade comprising a reference signal generator, a phased array antenna comprising at least one transmitter/receiver module comprising at least one level of phase shifted injection locked push-push oscillators, and radiating apparatus to generate a radar image.

23. Method 19, wherein said reference signal generator comprises a quartz oscillator.

Described are T/R (transmitter/receiver) modules for phased array antennas and for imaging radars generally.

Push-push oscillators are known. Injection locked oscillators are known. Art relevant for push- push oscillators and injection locked single ended oscillators includes the following publications: Yoon, S. W., etal. "A compact GaAs MESFET-based push-push oscillator MMIC using . . . ", 2001 IEEE GaAs Digest, p. 45 onward; Sinnesbichler, F. X. "Hybrid millimeter- wave push-push oscillators . . . ", IEEE Transactions on Microwave Theory and Techniques, Vol. 51(2),February 2003, p. 422 onward; Xiao, H. et al, "A low phase noise Ku-band push push oscillator . . . ", 2004 IEEE MTT-S Digest, p. 1333 onward; Ramirez, F. et al, "Nonlinear simulation techniques for the optimized design of push-push oscillators . . .", 2003 IEEE MTT- S Digest, p. 2157 onward; Dussopt, L. et al, "A low phase noise silicon 9 GHz VCO and an 18 GHz push-push oscillator", 2002 IEEE MTT-S Digest, p. 695 onward; Sinnesbichler et al, "A 38-GHz push-push oscillator . . . ", IEEE Microwaveand Guided Wave Letters, Vol. 9(4), April 1999, p. 151 onward; Kurokawa, K., "Injection locking of microwave solid-state oscillators", Proceedings of the IEEE, 61(10), October 1973, p. 1386 onward; Jezewski, M. T., "An approach to the analysis ofinjection-locked oscillators", IEEE Transactions on Circuits and Systems, CAS-21(3), May 1974, p. 395 onward; Plessas, F. and Kalivas, G., "Locking techniques for RF oscillators . . . ", ICECS-2003, p. 986 onward; Pavio. A. M. and M. A. Smith. "Push-push dielectric resonator oscillator", 1985 IEEE MTT-S Digest, p. 266 onward; Pavio, A. M and M. A. Smith, "A 20-40-GHz push-push dielectric resonator oscillator", IEEE Transactions on Microwave Theory and Techniques, MTT-33(12), December 1985, pp. 1346 onward; and Winch, R. G., "Wide-band varactor-tuned oscillators", IEEE Journal of Solid- State Circuits, Vol. SC-17(6), December 1982.

Provided is a improved phased array antenna comprising T/R modules based on injection locked push-push oscillators.

Provided is a method to simplify the receiving path of the T/R module, by demodulating the received signal immediately after the antenna, using a direct conversion mixer. Each receiving path preferably includes a receiving antenna and a receiver protector, a one-stage low noise amplifier (LNA) and a direct down converter. In contrast, in conventional high definition systems such as airborne radar systems, the receiving path typically includes, in addition to the elements described above, 3 switches, a multi-stage medium power amplifier and a phase shifter.

It is an object to reduce the production cost, size and weight of the main frame of the radar.

It is an object to reduce the complexity and the production cost of the T/R module.

It is also an object to eliminate, in the transmitting path of the T/R module, the loss caused by the phase shifter.

It is further an object to improve the linearity of the phase shift of the signal versus the operating frequency.

It is also an object to improve the third harmonic intercept point (IP3) of the RX (receiver), by limiting the size of the amplification chain of the LNA (low noise amplifier).

A preferred embodiment achieves all the above advantages by providing a chain of push-push oscillator circuits embedded in a T/R module constructed and operative in accordance with a preferred embodiment of the present invention, having one, some or all of the following characteristics and performing direct down conversion:

The conventional phase shifter is entirely eliminated.

The reference signal generated by the radar main frame has lower frequency than the radiated signal, such that the manifold is less affected by power loss.

The total phase shift of the signal is preferably partitioned between the individual push-push oscillator circuits, e.g. three levels of PS-IPPO may each effect a 120 degree phase shift giving a total 360 degree phase shift. Phase scan resultsare improved by the frequency multiplication which characterizes push-push oscillators. The structure of the main frame of the radar preferably makes use of components that are simpler, cheaper and smaller than corresponding conventional components.

The power of the signal delivered to each of the new T/R modules may be even lower than the level required by a traditional T/R module, such that the overall efficiency of the system is improved.

The mechanical structure of a high-definition phased array antenna, based on the T/R module shown and described herein and suitable for airborne radar applications, may be the same as the of conventional antennae of this genre, in which case the TX and RX modules may be integrated into the same mechanical housing.

There is thus provided, in accordance with a preferred embodiment, a reference signal generator comprising a quartz oscillator; and at least one level of push-push oscillators cascaded with the quartz oscillator.

Also provided, in accordance with a preferred embodiment, is a transmitter/receiver module comprising at least one level of push-push oscillators; and a receiving functionality receiving a sampled portion of power subsequently radiated by the push-push oscillators. Power which is to be radiated by the push-push oscillators is preferably sampled and the resulting sample is received by the receiving functionality.

Further provided, in accordance with a preferred embodiment, is radar imaging apparatus comprising a reference signal generator as above and a phased array antenna including at least one transmitter/receiver module and radiating apparatus cascaded with the reference generator and with at least one transmitter/receiver module.

Further in accordance with a preferred embodiment, the transmitter/receiver module comprises a plurality of levels of push-push oscillators.

Also provided, in accordance with a preferred embodiment, is injection locked push-push oscillator apparatus comprising a 0 degree power divider. The 0 degree power divider has the purpose of dividing a received reference signal having high stability and low noise characteristics into a first portion and a second portion, which is delayed by an odd multiple of 180 degrees relative to the first portion. These two signal portions enter two reflection amplifiers of the push-push oscillator, locking the signal already generated by the push-push oscillator. The locked signal has the same stability and noise characteristics as the reference signal.

Additionally provided, in accordance with a preferred embodiment, is imaging radar apparatus comprising a reference signal generator, at least one transmitter/receiver module as above, and radiating apparatus cascaded with a chain comprising the reference generator and at least one transmitter/receiver module.

Further in accordance with a preferred embodiment, the transmitter receiver module comprises at least one level of push-push oscillators.

Further in accordance with a preferred embodiment of the present invention, the receiving functionality comprises a direct balanced down converter.

Still further in accordance with a preferred embodiment, the reference signal generator comprises only two levels of push-push oscillators.

Additionally in accordance with a preferred embodiment, the reference signal generator comprises at least first and second levels of push-push oscillators.

Also provided, in accordance with a preferred embodiment, is a method for generating a reference signal for radar imaging, the method comprising cascading a quartz oscillator with at least one level of push-push oscillators.

Also provided, in accordance with a preferred embodiment, is a method for generating a radar transmitter/receiver module of a phased array antenna comprising providing at least one level of push-push oscillators and a receiving functionality.

Additionally provided, in accordance with a preferred embodiment, is a radar imaging method comprising cascading a reference signal generator comprising a quartz oscillator and at least first and second levels of push-push oscillators, a phased array antenna comprising at least one transmitter/receiver module, and radiating apparatus. Further in accordance with a preferred embodiment, the quartz oscillator is cascaded with a plurality of levels of push-push oscillators.

Additionally provided, in accordance with a preferred embodiment, is a method for injection locked push-push oscillation comprising dividing a received reference signal having stability and noise characteristics into a first portion and a second portion which is delayed by an odd multiple of 180 degrees relative to the first portion; and employing a push-push oscillator to receive the first and second portions and generate therefrom a locked signal having the stability and noise characteristics of the reference signal.

Further in accordance with a preferred embodiment, the method also comprises cascading a reference signal generator and radiating apparatus with the at least one level of push-push oscillators.

Additionally in accordance with a preferred embodiment, the transmitter receiver module comprises at least one level of push-push oscillators.

Further in accordance with a preferred embodiment, at loast one level of push-push oscillators comprises more than one push-push oscillator

Still further in accordance with a preferred embodiment, at least one level of push-push oscillators comprises only two levels of push-push oscillators.

Further in accordance with a preferred embodiment at least one individual level of push-push oscillators comprises more than one push-push oscillators.

Also provided in accordance with a preferred embodiment, is a radar imaging method comprising using a cascade comprising a reference signal generator comprising a quartz oscillator and at least first and second levels of push-push oscillators, a phased array antenna comprising at least one transmitter/receiver module, and radiating apparatus to generate a radar image.

Also provided, in accordance with a preferred embodiment, is a radar imaging method comprising using a cascade comprising a reference signal generator, a phased array antenna comprising at least one transmitter/receiver module comprising at least one level of push-push oscillators, and radiating apparatus to generate a radar image.

There is provided a push-push oscillator based transmitter/receiver module, suitable for high definition radar imaging applications.

There is provided high definition imaging radar apparatus based on an active phased array antenna which includes an array of transmitter/receiver modules such as but not limited to the transmitter/receiver modules.

There is provided a conventional high definition transmitter/receiver module.

There is provided an injection locked push-push oscillator based transmitter subsystem, suitable for commercial applications such as but not limited to automatic driving, in which a phase array antenna wavefront is to be steered both in azimuth and elevation.

Each one of the injection locked push-push oscillator-based transmitting units is operative to perform azimuthal steering in commercial applications such as but not limited to automatic driving.

There is provided a receiver subsystem which, in conjunction with the transmitter circuitry, forms an imaging radar system suitable for commercial applications such as but not limited to automatic driving.

There is provided a phase-scanned injection locked push-push oscillator (PS-IPPO) constructed and operative in accordance with a preferred embodiment of the present invention and suitable for implementing the phase-scanned IPPOs.

There is provided a composite band rejection filter (BRF), constructed and operative in accordance with a preferred embodiment of the present invention.

There is provided a reference signal generator, constructed and operative in accordance with a preferred embodiment of the present invention and including one or more constant phase injection locked push-push oscillators.

There is provided an injectable push-push oscillator.

There is provided a push-push oscillator-based transmitter/receiver module for high definition imaging radar. The term "high definition" is used herein to denote apparatus suitable for airborne radar applications and other applications which require considerable precision. The apparatus includes a reference signal generator 10, a cascade of at least one (three, in the illustrated embodiment) injection locked push-push oscillators 15, 20and 30 each receiving a signal at a given frequency and delivering a signal at an even multiple of the frequency of the injected signal (twice the incoming frequency in the illustrated embodiment), and each having a specific phase in accordance with system requirements, as described herein in detail; a digital tuned attenuator 40, a power amplifier 50, a coupler 55 to sample part of the transmitted power to be used as local oscillator by a mixer 90, also termed herein a "balanced direct down converter", a circulator 60, a radiator 65, a receiver protector 75 and a low noise amplifier 70. The mixer 90 typically outputs to a conventional digital signal processor (not shown).

The T/R module preferably forms part of a phased array antenna for high definition Imaging Radar. Among several other advantages, it eliminates the loss caused, in a conventional T/R module, by the phase shifter. The transmitting path of the T/R module, according to a preferred embodiment of the present invention, comprises a chain of 3 injection locked push-push oscillators 15, 20 and 30; a digital tuned attenuator 40, a power amplifier 50, a coupler 55, a circulator 60 and a transmitting radiator 65. In contrast, the transmitting path in conventional high-definition systems typically comprises three switches, (300, 310, 320), a digitally tuned attenuator 360, a multi-stage medium power amplifier 370, a phase shifter, a power amplifier, a circulator 355 and a radiator 365. The 3 switches, the phase shifter, the multi-stage medium power amplifier and the digitally tuned attenuator are typically common to the transmitting and receiving paths in conventional systems.

When the system is performing the full phase scan, each of the oscillators typically operates within a range which is much narrower than the pulling band which generates a safely locked operating condition.

At the output of the injection locked phase shifted push-push oscillator chain, a radiator 65 is connected to radiate the RF signal, with the appropriate phase shift.

According to a first embodiment of the present invention suitable for high definition applications, the RX radiator is typically one and the same as the TX radiator (both denoted by reference numeral 65), and the combined radiator is operated by the circulator 60, and by switching suitably between TX and RX. According to a second embodiment of the present invention suitable for commercial applications, the TX antenna of the transmitting subsystem is typically located adjacent the RX antenna of the receiving subsystem, typically at the closest distance at which the transmitter does not significantly affect the receiver.

There is provided apparatus for imaging radar including a radar mainframe 100, a manifold 110, and a phased array antenna 180 typically comprising an array of transmitter/receiver modules 120, 130, 140and 150. Each T/R module may be constructed and operative, or alternatively may be a conventional T/R module e.g. as shown and described below. The wavefront of the apparatus above is denoted by reference numeral 170. The steering angle ALPHA is denoted by reference numeral 160.

There is provided a conventional (prior art) transmitter/receiver module including first, second and third switches 300, 310 and 320 which select either a transmitting path or a receiving path. The selection, indicated by the specific position of the three switches, is the receiving path. The receiving path comprises a radiator 365, a circulator 355, a receiver protector 340, a multistage low noise amplifier 350, the third switch 320, a digitally tuned attenuator 360, a typically multi-stage medium power amplifier 370, a phase shifter 380, switch 310 and switch 300. The transmitting path comprises the first switch 300, the second switch 320, a digitally tuned attenuator 360, atypically multi-stage medium power amplifier 370, the phase shifter 380, the second switch 310, a typical multi-stage power amplifier 360, the circulator 355 and the radiator 365.

Phased array antennas generally comprise an array of radiators, each one connected to a T/R module, radiating a signal with a specific phase, related to a given phase reference. In conventional T/R modules, the component which is operative to change the phase of the radiated signal is a circuit termed a "phase shifter". There are several configurations for the phase shifter component all of which are expensive to produce, particularly in MMIC technology. In conventional systems, the input signal to the T/R module has the same frequency as the radiated signal. Among other disadvantages present in a conventional T/R module, as described hereinbelow, the "manifold" (distribution network of the signal to the various T/R modules) is adversely affected by an appreciable power loss, which is an increasing function of the operating frequency. The size and the weight of the manifold are also disadvantages in conventional airborne high definition phased array antennas.

The high frequency of the signal fed into the conventional T/R module results in the main frame of conventional radar systems being forced to incorporate expensive circuitry having relatively high DC power consumption, such as PLL controlling high frequency oscillators, frequency prescalers, and power amplifiers. Each T/R module, in addition to operating the phase shift, also preferably performs the function of increasing the power of the signal received at its input port.

In conventional T/R modules, due to the presence of the phase shifter, the phase shifter's loss, typically of the order of 5-7 dB, needs to be recovered, thereby reducing efficiency.

In radar "Frequency Agility" operations, the beam focus of the Radiation Pattern of the antenna (which determines the ability of the system to adequately track its target), is adversely affected by the non-linearity of the phase shifter versus frequency. Mainly in high frequency, and in MMIC technology, the screening of the components lowers the production yield of the item, thereby increasing its production cost. The power loss related to the phase shifter, when switched to the receiving path, reduces the system's Third Harmonic Intercept Point, (IP3). The power loss related to the manifold, switched to the receiving path, further reduces the system's efficiency.

There is provided an injection locked push-push oscillator based transmitter subsystem, operative to steer a phased array antenna wavefront in both azimuth and elevation in commercial applications such as but not limited to automatic driving. The circuitry includes a reference signal generator 400, and multi-module transmitting units 430 and 435. Unit 435 receives an input signal at the same power and frequency as does transmitting unit 435, but with a 180 degree phase shift introduced by 180 degree delay unit 420. The DSP 610 operatively associated with the transmitter subsystem and the receiver subsystem provides azimuth steering information obtained from the transmitting units 430 and 435 and computes elevation steering information. There is provided a complete phased array antenna system for imaging radar, suitable for commercial applications such as but not limited to automatic driving applications.

Separation of the TX modules and antenna from the RX modules and antenna is believed to yield the most cost effective solution for commercial systems such as FMCW (frequency modulated continuous wave) systems, for automatic driving.

The apparatus described herein preferably simplifies the re ceiving path of the T/R module, by demodulating the received signal immediately after the radiator, using a direct conversion mixer. Each receiving path, according to a first embodiment of the present invention suitable for commercial applications, includes a receiving antenna and a direct down converter.

Transmitting units 430 and 435 may receive signals identical in power level and frequency but with phases of 0 and 180 degrees respectively. Each comprises an injection locked push-push oscillator-based transmitter typically operative to perform only azimuthal steering in commercial applications such as automatic driving. As shown, a plurality of stages of push- push oscillators may be employed, at least one of the stages including more than one push-push oscillator. In the illustrated embodiment, three stages of push-push oscillators are provided, the first including a single oscillator 510, the second including two oscillators 530 and 540 and the third including four oscillators 570, 580, 585 and 590.

All of the injection locked push-push oscillators (IPPOs) in the apparatus are typically phase scanned (PS) and may comprise the phase-scanned IPPO. The phase shift generated in the present invention is analogical. As such,it can be affected by phase drift due to component aging or fluctuation in temperature. In order to secure a focused radiation pattern beam of the

TX antenna, based on the injection locked push-push oscillators (IPPOs), the phase of the last circuit of the chain of each TX module (e.g. modules 570, 580, 585, and 590) is periodically compared and aligned to a reference phase (e.g. the phase of the signal of module 590), using a phase detector. For example, , the phase of the signal radiated by PS-IPPO 585 may be compared, and aligned, to the reference signal of PS-IPPO 590 by phase detector 587.

Subsequently, the phase radiated by PS-IPPO 580 may be compared, and aligned, to the new reference, namely the phase of PS-IPPO 585, by phase detector 582. Subsequently, the phase radiated by PS-IPPO 570 may be compared, and aligned, to the latest reference, namely the phase of PS-IPPO 580, by phase detector 575. Typically, the resulting feedback is employed, periodically and/or as necessary, e.g. once a minute, to restore the focus of the radiated beam.

Phase detectors 575, 582, and 587 may have the same basic structure as the balanced direct down converters described hereinbelow. However, they are typically differently tuned. Whereas the converters described below are tuned by converting RF signals into baseband signals, the phase detectors are tuned to detect the phase between the two RF input signals having the same frequency. Each phase detector receives a pair of same-power, same- frequency RF signals that may differ in phase.

The receiver subsystem makes use of a sampled portion of the signal, generated by a homologous transmitter, as pump for the transmitter's corresponding mixer.

Each one of the receivers 640, 650, 660 and 670 typically comprises a receiver protector 680, followed by a low noise amplifier (LNA) 685 and a balanced direct conversion mixer 690. Suitable circuitries for the balanced direct conversion mixer 690, according to two alternative embodiments of the present invention, are shown below, respectively.

The pump for each RX module is typically sampled from the corresponding (homologous) TX module. The term "LO signal" refers to the local oscillator signal of the corresponding receiver (640, 650, 660 or 670). The output from the RX module is directly at base band, and is fed into a digital signal processor (DSP) 610.

The DSP elaborates the data from the echo of the radar, and generates the information for imaging operations. A screen display (not shown) typically displays the image of the target.

A phase-scanned injection locked push-push oscillator (PS-IPPO) has characteristics specifically tailored to the functionality of a T/R module. Specifically, each phase-shifted injection locked push-push oscillator of the present invention (e.g. oscillators 15, 20 and 30; oscillators 510, 530, 540, 570, 580, 585 and 590) typically receives an injecting RF signal, multiplies its frequency by a factor of 2*N, where N is an integer, and changes its phase thereby inherently enhancing the phase scan of the system. The stability of the output signal is typically the same as the stability of the injecting signal and the output signal's noise spectrum typically degrades only slightly due to the frequency multiplication. There is provided a composite BRF for injection block 710, constructed and operative in accordance with a preferred embodiment of the present invention.

There is provided a reference signal generator, constructed and operative in accordance with a preferred embodiment of the present invention and including one or more constant phase injection locked push-push oscillators (CP-IPPOs) 910 . . . , 920. The output of the last CP- IPPO 920 is injected into a T/R module constructed and operative in accordance with a preferred embodiment of the present invention. A preferred embodiment of thepresent invention comprises two chains of push-push oscillators constructed and operative in accordance with a preferred embodiment of the present invention, e.g. phase shifted IPPOs 15, 20 and 30 and constant phase IPPOs 1, . . . M. Alternatively, only one of these chains may be employed.

The master reference signal is generated by a quartz oscillator 900. The reference signal is characterized by very high stability and very low noise. A first chain of M push-push cascaded stages 910, . . . 920, used as constant-phase frequency multipliers, multiplies the frequency of the master signal by a maximum factor (2*N)**M, where N is an integer, as shown below.

In commercial applications, the T/R module's quartz master may work at UHF (ultra high frequency) e.g. 150.39 MHz: the reference signal inputting the T/R modules, after the frequency multiplication by the first chain of push-push circuits, may have a frequency of 9.625 GHz. The radiated signal frequency may reach the desired level, 77 GHz, after frequency multiplication by the second chain of PS-IPPOs. In order to achieve such a result, the first chain's parameters may be N=4 and M=2, while the parameters of the second chain may be N=l and M=3, (multiplication factor={(2*N)**M}).

If the above example parameters are used for the first and second chains of a high definition T/R module constructed and operative in accordance with a preferred embodiment of the present invention, the radiated frequency is e.g. 10 GHz, the reference signal inputting the T/R module is 1.250 GHz, and the frequency of the quartz master oscillator 19.53 MHz.

The very low operating frequency of all the above-described circuits results in a considerable saving in production cost for high definition imaging radar as well as higher system reliability, relative to conventional T/R modules. The push-push oscillator constructed and operative in accordance with a preferred embodiment of the present invention is convenient to cascade, so that no circulators are needed for isolating the stages, as requested by conventional frequency multipliers. The first chain of push-push oscillators 910, . . . 920 makes up the RF portion of the radar main frame.

Constant phase injection locked push-push oscillators comprise a power splitter 1200 typically operative to directly inject one half of the received power into a band rejection filter (BRF) 1210 and to inject the second half of the received power into the band rejection filter 1210 via a 180 degree delay unit 1270. A pair of reflection amplifiers 1230 and 1240 feed into a power combinerl250 and a filter 1260. The filter may be tuned at 2*N*fO where N is an integer such as 4.

Tje direct down converter 90 or 690 typically includes a rat racepower divider 1300 (micro strip "magic tee"), two biased diodes 1310 and 1320, a filter 1330 feeding into an output DSP (digital signal processor).

There is provided an alternative, in-phase quadrature phase mixer (I/Q mixer) embodiment of the balanced direct down converter 90 or 690. The apparatus comprises a 90 degree power divider 1400, a pair of balanced direct down converters 1410 and 1420 and a zero-degree power splitter 1430.

A suitable layout is provided for the radiator array 595, and/or for either or both of the radiator arrays 675 and 675A. In order to perform only azimuth steering of the transmitted beam, the signals to the connections A, . . . , H have the following phases respectively: 0, gamma, 2*gamma, 3*gamma, 180, 180+gamma, 180+2*gamma, 180+3*gamma. In order to perform only elevation steering, the signals to the same connections A-H have the following phases respectively: 0, 0, 0, 0, beta, beta, beta, beta. In order to perform any combined steering, a combination of the mentioned phases is used. Gamma and beta are antenna-dependent coefficients if very low side lobes of the radiation pattern are desired; in the illustrated embodiment, gamma may be between -125 degrees and 125 degrees whereas beta may be between -90 degrees and 90 degrees. If gamma is +/-125 degrees and beta is +/-90 degrees, the azimuth will be +/-32 degrees and the elevation angle will be +/-3 degrees, respectively.

The phase shift function of the injection locked push-push oscillator is now described: Given a generic injection locked oscillator locked at fO, if the frequency of the injection locking signal is changed, the output frequency is then pulled by the reference signal. Out of the locking band, the circuit degrades to become a free running oscillator. Similarly, given a generic injection locked oscillator, locked at the aligned frequency ft), if the BRF of the circuit is tuned to a different frequency within the pulling bandwidth, the frequency of the output signal remains obviously the same, but the phase of the output signal changes.

The advantage of the injection locked push-push oscillator circuit based embodiment over single ended oscillators is the inherent frequency and the phase multiplication of the processed signal, which result in a smaller and less costly system as described above.

The inherent frequency multiplication makes the radar main frame cheaper, smaller and lighter, while the phase multiplication enhances the scan phase of the system and relieves the system of the expensive phase shifter circuit.

The push-push oscillator based embodiment described herein has major economical advantages even vis a vis a novel T/R module which might be based on single ended oscillators. In order to enhance the phase scan of a usual inject-locked single ended oscillator, a frequency multiplier should be cascaded to it. Because of the high criticality of the circuits involved, this operation requires a circulator, which is a large, costly component.

There is provided a suitable layout for an injectable push-push oscillator such as PS-IPPO 30. The circuitry of all the PS-IPPOs and CP-IPPOs described herein, if MMIC-based, may be scaled to the width and length of each individual IPPO's transmission lines.

There is provided a suitable layout for the balanced down converter. The technology of the T/R module components is typically MMIC on Indium Phosphate or Gallium Arsenide substrates. The MMIC components are typically assembled in an LTCC environment, which will imbed the RF and DC connections, as well as the printed antenna on the external side.

A particular advantage is to lower the production cost of a phased array antenna system, including a T/R module thereof and a reference signal generator thereof, for any given frequency of the radiated signal. Typically, the output signal of the first chain of push-push oscillators is characterized by high stability, low noise and frequency which is high, albeit lower than the frequency of the signal radiated by the T/R module. The output of the last IPPO in the chain is injected into a T/R module constructed and operative in accordance with a preferred embodiment of the present invention. The T/R module preferably comprises a chain of at least one stage of injection locked phase-shifted push-push oscillators. The frequency of the signal fed to the T/R module is multiplied by every stage of injection locked push-push oscillator, until the intended radiation frequency is achieved. The phase of the processed signal is scanned by every stage, in accordance with system requirements. Typically, the signal generated by each of the injection locked push-push oscillators of the T/R module constructed and operative in accordance with a preferred embodiment of the present invention is appropriately phase shifted such that the radiated signal has a potential phase scan of 360 degrees.

The term "commercial", as opposed to "high definition", is used herein to denote non-military radar applications such as but not limited to automatic driving applications.

Features of the present invention which are described in the context of separate embodiments may also be provided in combination in a single embodiment. Conversely, features of the invention which are described for brevity in the context of a single embodiment may be provided separately or in any suitable subcombination.

Other References relevant to push-push oscillators include:

• Pavio, A. M and M. A. Smith, "Push-Push dielectricresonator Oscillator", 1985 IEEE

MTT-S Digest, p. 266-269.

• Winch, R. G., "Wide-Band Varactor-Tuned Oscillators"; IEEE Journal of Solid-State

Circuits, vol. SC-17, No. 6, Dec. 1982: pp. 1214-1219.

• Pavio A.M and M. A. Smith, "A 20-40-GHz Push-Push Dielectric Resonator oscillator";

IEEE Transactionson Microwavetheoryand Techniques, vol. MTT-33, No. 12 Dec. 1985; pp. 1346-1349.

• Plessas, F. and Kalivas, G., "Locking Techniques for RF Oscillators at 5— 6 GHz

Frequency Range"; ICECS-2003; pp. 986-989. • Jeiewski, M. T., "An Approach to the Analysis of Injection-Locked Oscillators"; IEEE

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Also provided is a method for making any of the systems shown and described herein including providing all or any suitable subset of the system components shown and described herein, using any suitable conventional methodology, and a method for using any and all such systems and such components as would be apparent from the structure and function thereof as described herein.

Features of the present invention which are described in the context of separate embodiments may also be provided in combination in a single embodiment. Conversely, features of the invention, including method steps, which are described for brevity in the context of a single embodiment or in a certain order may be provided separately or in any suitable subcombination or in a different order.

Claims

1. A communication network system comprising:

A plurality of nodes at least one of which comprising a transceiver interfacing with an antenna which is operative to transmit and receive an electronically steerable focused electromagnetic beam.

2. A system according to claim 1 Wherein the beam is steerable using a phase shifting functionality provided by a PSIPPO (phase shift injected push push oscillator).

3. A system according to claim 1 Wherein said antenna is circularly polarized, thereby to enable transmission and reception of an electromagnetic beam regardless of the spatial orientation of the transmitting and receiving transceivers.

4. A system according to claim 1 Wherein said antenna has a bandwidth of approximately 10% centered at approximately 60 GHz.

5. A system according to claim 1 or claim 4 and wherein said plurality of nodes comprises at least one pair of nodes comprising first and second nodes which lack a line of sight between them, and, for each such pair, at least one repeater node having a line of sight to both of said first and second nodes. ⁱ

6. A system according to claim 5 whereirl said at least one repeater node includes at least one repeater node serving more than one pair of nodes which lack a line of sight between them.

7. A system according to claim 1 and also comprising a software management functionality operative to enable simultaneous transmission and reception between more than one pair of nodes from among said plurality of nodes by dividing at least one transceiving resource between active nodes.

8. A system according to claim 7 wherein said software management functionality employs TDMA.

9. A system according to claim 7 wherein said software management functionality employs FDMA.

10. A system according to claim 7 wherein said software management functionality employs CDMA.

11. A system according to claim 1 wherein said focused electromagnetic beam is steered using AESA technology.

12. A system according to claim 1 wherein said plurality of nodes also includes at least one MIMO node.

13. A system according to claim 6 wherein a sequence of repeater nodes with a line of sight and less than a predetermined distance between them serves each pair of nodes separated by more than said predetermined distance.

14. A system according to claim 13 wherein said predetermined distance is at least 10 meters.

15. A system according to claim 1 wherein said antenna has a bandwidth of approximately 57 -64 GHz.