WO2008032886A1

WO2008032886A1 - Antenna for wireless communication and method of fabricating the same

Info

Publication number: WO2008032886A1
Application number: PCT/KR2006/003680
Authority: WO
Inventors: Dong Hyun Lee
Original assignee: Acetronix Co Ltd
Current assignee: Acetronix Co Ltd
Priority date: 2006-09-15
Filing date: 2006-09-15
Publication date: 2008-03-20
Anticipated expiration: 2009-03-15

Abstract

The present invention relates to an antenna for wireless communication and method of fabricating the antenna. The antenna of the present invention includes a square pillar-shaped dielectric ceramic body (10) having a rectangular through-hole (12) formed in the center portion thereof and having an outer surface on which first and second electrode patterns (20 and 25) are formed. A first PCB (30) is inserted into the through-hole formed in the center of the ceramic body and provided with a conductive stripline formed thereon. A second PCB (35) is formed to extend from a first end of the first PCB and to be integrated with the first PCB, and includes an impedance matching unit. A shield can (40) is in contact with one surface of the second PCB, and to a method of fabricating the antenna. Accordingly, productivity is improved, and excellent antenna characteristics can be obtained.

Description

[invention Title]

ANTENNA FOR WIRELESS COMMUNICATION AND METHOD OF FABRICATING THE SAME

[Technical Field] The present invention relates, in general, to an antenna for wireless communication and, more particularly, to an antenna, which includes a square pillar-shaped dielectric ceramic body having a rectangular through-hole formed in the center portion thereof and having an outer surface on which first and second electrode patterns are formed; a first PCB inserted into the through-hole formed in the center portion of the ceramic body and provided with a conductive stripline formed thereon; a second PCB formed to extend from a first end of the first PCB and to be integrated with the first PCB, the second PCB including an impedance matching unit; and a shield can that is in contact with one surface of the second PCB, and to a method of fabricating the antenna. The structure and components of the antenna according to the present invention are improved, so that productivity is improved, and excellent antenna characteristics can be obtained, thus enabling the antenna to be applied to various types of electronic communication devices.

[Background Art]

The present invention relates, in general, to an antenna for wireless communication and a method of fabricating the antenna and, more particularly, to a high performance antenna for wireless communication., in which a Printed Circuit Board

(PCB) , including a feeder line, is inserted into a square pillar-shaped ceramic body, and which includes a balun therein.

Recently, with the rapid development of mobile communication and satellite communication, the role of wireless communication is becoming more important in information society. Wireless communication technology, starting from voice-oriented narrow band communication, is rapidly moving toward wideband communication, such as the Internet or multimedia communication. Currently, the advent of new wireless services, such as International Mobile Telecommunications (IMT) -2000 and fourth generation mobile communication using ultrahigh speed mobile communication, has been expected. The technology for forming the base of such wireless communication is antenna technology, and the performance thereof influences the quality of communication, and thus the importance of antenna technology has gradually been increasing.

An antenna is a device functioning to efficiently radiate radio waves into space or to efficiently induce an electromotive force using radio waves, in order to achieve the purpose of wireless communication.

Antennas are classified into several types according to the structure and functionality thereof, that is, they are classified into antennas for long and medium waves, short waves, and ultrashort waves, according to the usable frequency, they are classified into antennas for broadcasting, typical communication, direction finding, navigation, satellite communication, and radio telescopy, according to the purpose of the use thereof, they are classified into a standing-wave antenna, a traveling wave antenna, and a log periodic antenna according to the principle of operation, they are classified into an isotropic antenna, an omnidirectional antenna, a unidirectional antenna, and a bilateral antenna according to directivity characteristics, they are classified into a linearly polarized antenna, a circularly polarized antenna, and an elliptically polarized antenna according to polarization characteristics, and they are classified into a wideband antenna, a narrow band antenna, a positive impedance antenna, and a tuned antenna according to the frequency characteristics thereof .

In the structure of an antenna, the antenna includes an extension coil or a loading condenser, which increases or decreases the resonance frequency of the antenna, a trap, which is a coil used when radio waves having various frequencies are intended to be used, and feeder lines, which feed electric energy, in addition to elements, which are parts for actually transmitting or receiving radio waves. Among the feeder lines, an electric wire composed of an external conductor and an internal conductor is a coaxial cable.

Important characteristics required for an antenna include impedance characteristics and gain. When the impedance values of an antenna and a coaxial cable are matched with each other, radio waves are most effectively transmitted, and thus impedance matching is very important. Further, if an antenna having a high gain is used, communication with a radio station located far away from the antenna is possible using only low power.

Recently, an antenna having excellent performance has been required for application fields such as a Global Positioning System (GPS) , Digital Multimedia Broadcasting (DMB) , or Radio Frequency Identification (RFID) . In particular, the demand for a new antenna, for which impedance matching is excellent and maintenance of quality during a manufacturing procedure is easy, has increased.

[Disclosure]

[Technical Problem]

Accordingly, an object of the present invention is to provide an antenna for wireless communication, which has a new structure for performing excellent impedance matching. Another object of the present invention is to provide a new antenna for wireless communication, which has a new structure for improving productivity and making it easy to maintain the quality of communication.

Other objects and features of the present invention will be described in detail in the following detailed description.

[Technical Solution]

In order to accomplish the above objects, the present invention provides an antenna for wireless communication, comprising a square pillar-shaped dielectric ceramic body having a rectangular through-hole formed in a center portion thereof, and having a first electrode pattern and a second electrode pattern formed on an outer surface thereof; a first Printed Circuit Board (PCB) inserted into the through-hole formed in the center portion of the ceramic body and provided with a conductive stripline formed thereon; a second PCB formed to extend from a first end of the first PCB and to be integrated with the first PCB, the second PCB comprising an impedance matching unit; and a shield can that is in contact with a first surface of the second PCB. Preferably, the first electrode pattern may be spirally formed on an upper portion of the outer surface of the ceramic body. Preferably, the second electrode pattern may be formed to have a predetermined area on a lower portion of the outer surface of the ceramic body, and may be electrically connected to the first electrode pattern.

Further, the present invention provides a method of fabricating an antenna for wireless communication, comprising forming a square pillar-shaped dielectric ceramic body having a through-hole formed in a center portion thereof; forming a first electrode pattern on a first portion of the ceramic body and forming a second electrode pattern on a second portion of the ceramic body to be electrically connected to part of the first electrode pattern; fabricating a first Printed Circuit Board (PCB) comprising a feeding stripline, and a second PCB comprising an impedance matching unit so that the first and second PCBs are formed to be integrated with each other; inserting the first PCB into the through-hole of the ceramic body; and attaching a shield can to a first surface of the second PCB.

The antenna for wireless communication according to the present invention is implemented by improving and developing a loop antenna and applying a ceramic body, is used in wireless communication using frequencies of 100MHz to 10GHz, has the characteristics of circular polarization, and is capable of being applied in many application fields, such as mobile communication, a Global Positioning System (GPS) , a Wireless Local Area Network (WLAN) , Digital Multimedia Broadcasting (DMB) , and Radio Frequency Identification (RFID) .

Further, the antenna for wireless communication according to the present invention is implemented using a ceramic material to considerably reduce the size thereof, adopts a feeding method using a laminate PCB, which includes a conductive stripline, and is manufactured so that a ceramic body is formed in a square pillar-shape and the laminate PCB is inserted into the ceramic body, thus facilitating the assembly of the antenna and greatly simplifying the entire manufacturing process. Therefore, the manufacturing costs and productivity of the antenna can be remarkably improved, and the antenna can be easily mounted in various electronic devices .

Further, since the antenna of the present invention is a balanced antenna having a balun (balance to unbalance transformer) therein and is less influenced by surrounding objects, the antenna is stable. The antenna of the present invention is implemented so that a second electrode pattern is formed on a ceramic body and a circuit for impedance matching is constructed on a second PCB in order to realize a balun, thus the antenna itself includes the balun. Accordingly, the present invention can exhibit more stable antenna performance.

[Description of Drawings]

FIG. Ia is a perspective view showing the appearance of an antenna according to the present invention;

FIG. Ib is a perspective view showing the assembly of the antenna according to the present invention; FIG. 2 is a graph showing return loss data related to the input impedance of the antenna according to the present invention;

FIG. 3 is a graph showing the Smith Chart related to the input impedance of the antenna according to the present invention;

FIG. 4 is a graph showing the axial ratio of the antenna according to the present invention; and

FIG. 5 is a graph showing the elevation radiation pattern of the antenna according to the present invention. description of reference characters of important parts>

10 : ceramic body 12 : through-hole

20: first electrode pattern 25: second electrode pattern

30: first PCB 35: second PCB

40: shield can

[Best Mode] Hereinafter, embodiments of the present invention will be described in detail with reference to the attached drawings. FIG. Ia is a perspective view showing the appearance of an antenna according to the present invention, and FIG. Ib is a perspective view showing an assembly procedure for combining components constituting the antenna with each other.

A ceramic body 10, corresponding to the body of the antenna, is made of a dielectric, electronic ceramic material and is formed in a square pillar shape. The permittivity of the ceramic body preferably has a range from 5 to 130.

A through-hole 12 is formed in the center portion of the ceramic body 10. The through-hole 12 is a space into which a

Printed Circuit Board (PCB) for feeding, which will be described later, is to be inserted, and preferably has a square pillar shape for facilitating the assembly of the antenna.

Two types of electrode patterns are formed on the outer surface of the square pillar-shaped ceramic body 10. A first electrode pattern 20 is formed on the upper portion of the outer surface of the ceramic body 10, is spirally formed, and is implemented in a shape in which two loop antennas are arranged to be orthogonal to each other and are twisted together. The first electrode pattern 20 is the electrode for transmitting or receiving radio waves, and is made of a conductive material.

A second electrode pattern 25 is formed on the lower portion of the outer surface of the ceramic body 10. The second electrode pattern 25 is formed to surround the outer surface of the ceramic body 10, unlike the first electrode pattern 20. The second electrode pattern 25 has a part electrically connected to the first electrode pattern 20, and is an electrode required to implement a balun. That is, the second electrode pattern 25 connects an unbalanced feeding unit (a first PCB for feeding which will be described later) to a balanced antenna (the first electrode pattern) .

The second electrode pattern 25 can be made of the same conductive material as the first electrode pattern 20.

A feeding structure to be inserted into the through-hole 12, formed in the center portion of the ceramic body 10, is formed using a Printed Circuit Board (PCB) , and has a conductive stripline (not shown) formed in the PCB. The feeding structure is divided into two parts. A first PCB 30 is a feeding unit for supplying electricity to the first electrode pattern, and a second PCB 35 is a circuit unit required for impedance matching. As shown in the drawing, the first PCB 30 and the second PCB 35 are preferably formed such that they are integrated with each other.

A printed circuit pattern (not shown) required for impedance matching is formed on the second PCB 35. This printed circuit pattern can be implemented using a conductive stripline or a micro stripline. A printed circuit pattern for signal amplification can be further provided on the second PCB 35, in addition to the printed circuit pattern for impedance matching. In this case, active parts and passive parts are included in the signal amplification circuit .

On the surface of the second PCB 35, on which the printed circuit pattern is formed, a shield can 40, which is a shielding film for protecting the printed circuit pattern for impedance matching (or impedance matching + signal amplification) from electromagnetic interference, is provided. The shield can 40 can be made of, for example, a conductive material.

The method of fabricating the antenna for wireless communication according to the present invention is described below.

The ceramic body is molded using a method of pressurizing dielectric ceramic powders, etc. so that the exterior thereof is formed in a square pillar shape and the interior thereof has a rectangular through-hole. The molded ceramic body is sintered in an electric furnace.

After the sintering has been completed, patterns are formed. The first and second electrode patterns are formed in such a way that a pattern is formed on each surface of the ceramic body using a conductive metal material, for example, silver paste, in a preferred embodiment of the present invention, through a printing method. The formed patterns are baked in the electric furnace. The first and second electrode patterns can be formed using a plating method.

Both the first PCB and the second PCB can be manufactured in such a way that a stripline for feeding and a printed circuit pattern for impedance matching are designed on a single PCB, and a typical printing method is utilized. The section of the first PCB is fabricated to have the same shape as the section of the through-hole of the ceramic body. Finally, after the shield can has been fabricated, the first PCB is inserted into the center portion of the ceramic body and is connected to the ceramic body through soldering, and the shield can is also attached to the second PCB through soldering .

An antenna for wireless communication, the ceramic body of which has a sectional size of lOmmXδmm and has a length of

18mm, was fabricated, and the electrical characteristics thereof were examined. The center frequency was 1574.42 MHz, the bandwidth was 10 MHz [Min] , the Voltage Standing Wave Ratio

(VSWR) was 2.0 [Max. ] , the gain was -6.0 dBi , and the temperature coefficient was 0±20 ppm/^°C. The antenna exhibited the characteristics of circular polarization.

Referring to FIGS. 2 and 3, showing input impedance values, it can be seen that a GPS frequency is 1.57542 GHz and exhibits an excellent value, and that the input impedance of the antenna is excellently matched to 50 Ω in a bandwidth of about 25 MHz (return loss is equal to or less than -1OdB) .

Referring to the pattern of FIG. 4, it can be seen that, when the antenna is rotated, variation in the difference between received values (axial ratio) is below 2 dB, and is excellent. Referring to the radiation pattern of FIG. 5, it can be seen that the antenna has a beam width of 120^° or more.

[industrial Applicability] As described above, the present invention provides a new antenna, which realizes excellent productivity through structural improvement, and also exhibits excellent resultant electrical characteristics. The antenna of the present invention can be widely applied to various types of electronic communication devices.

Claims

[CLAIMS]

[Claim l]

An antenna for wireless communication, comprising: a square pillar-shaped dielectric ceramic body having a rectangular through-hole formed in a center portion thereof, and having a first electrode pattern and a second electrode pattern formed on an outer surface thereof; a first Printed Circuit Board (PCB) inserted into the through-hole formed in the center portion of the ceramic body and provided with a conductive stripline formed thereon; a second PCB formed to extend from a first end of the first PCB and to be integrated with the first PCB, the second PCB comprising an impedance matching unit; and a shield can that is in contact with a first surface of the second PCB.

[Claim 2]

The antenna for wireless communication according to claim

1, wherein the first electrode pattern is spirally formed on an upper portion of the outer surface of the ceramic body.

[Claim 3]

The antenna for wireless communication according to claim

2, wherein the second electrode pattern is formed to have a predetermined area on a lower portion of the outer surface of the ceramic body, and is electrically connected to the first electrode pattern.

[Claim 4]

The antenna for wireless communication according to claim 1, wherein the second PCB further comprises a signal amplification unit.

[Claim 5]

The antenna for wireless communication according to claim 1, wherein the first electrode pattern and the second electrode patterns are made of conductive paste.

[Claim 6] The antenna for wireless communication according to claim 1, wherein the first electrode pattern has a shape in which two loop antennas are orthogonal to each other.

[Claim 7]

A method of fabricating an antenna for wireless communication, comprising: forming a square pillar-shaped dielectric ceramic body having a through-hole formed in a center portion thereof; forming a first electrode pattern on a first portion of the ceramic body and forming a second electrode pattern on a second portion of the ceramic body to be electrically connected to part of the first electrode pattern; fabricating a first Printed Circuit Board (PCB) comprising a feeding stripline, and a second PCB comprising an impedance matching unit so that the first and second PCBs are formed to be integrated with each other; inserting the first PCB into the through-hole of the ceramic body; and attaching a shield can to a first surface of the second PCB.

[Claim 8]

The fabricating method according to claim 7, wherein the first electrode pattern is formed in a shape in which two loop antennas are orthogonal to each other.

[Claim 9]

The fabricating method according to claim 7, wherein the second PCB further comprises a signal amplification unit.

[Claim lθ] The fabricating method according to claim 7, wherein the first and second electrode patterns are made of conductive paste .