TWI622274B - System and method for testing radio frequency wireless signal transceivers using wireless test signals - Google Patents

Abstract

A method of facilitating wireless testing of multiple radio frequency (RF) signal transceiver test units (DUTs). Maximum radiation can be maximized by controlling the individual signal phases of multiple radio frequency (RF) test signals radiated to the device under test (DUT) using multiple antennas within a shielded enclosure containing the device under test (DUT) The direct-coupled signal of the target device under test (DUT) while minimizing the cross-coupled signal. Furthermore, the direct-coupled signal radiated to its individual target device under test (DUT) can be normalized by controlling the individual signal magnitude of the radio frequency (RF) test signal radiated to the device under test (DUT). At the same time, it is still sufficient to reduce the cross-coupling signal. Thus, compensation for the multipath signal environment within the shielded enclosure is provided, thereby simulating a wired test signal path in a wireless test of the device under test (DUT).

Description

System and method for testing radio frequency wireless signal transceiver using wireless test signal

This invention relates to testing radio frequency (RF) wireless signal transceivers, and in particular to testing such devices without the use of radio frequency (RF) signal cables carrying radio frequency (RF) test signals.

Related application

This application is a continuation of U.S. Patent Application Serial No. 13/839,162, filed on March 15, 2013, entitled "System and Method for Testing Using Wireless Test Signals to Test RF Wireless Signal Transceivers" Radio Frequency Wireless Signal Transceivers Using Wireless Test Signals), and a continuation of the US Patent Application No. 13/839,583, filed on March 15, 2013, entitled "Using Wireless Test Signals to Test Radio Frequency Wireless" System and Method for Testing Radio Frequency Wireless Signal Transceivers Using Wireless Test Signals, the entire disclosures of which are incorporated herein by reference.

Many modern electronic devices use wireless technology for both connection and communication purposes. Because the wireless device transmits and receives electromagnetic energy, and because two or more wireless devices These devices may interfere with each other's operation due to their signal frequency and power spectral density. These devices and their wireless technologies must comply with various wireless technology standard specifications.

When designing such devices, engineers must pay extra attention to ensure that such devices meet or exceed each of the wireless technology they specify to comply with standards-based specifications. Furthermore, when these devices are mass produced in the future, they will be tested to ensure that production defects do not result in improper operation, including whether they comply with the standards based on the included wireless technology.

In order to test these devices after production and assembly, current wireless device test systems ("testers") utilize a subsystem to analyze signals received from each device. The subsystems typically include at least a vector signal generator (VSG) for providing a source signal to be transmitted to the device, and a vector signal analyzer (VSA) for analyzing signals generated by the device. . The test signals generated by the VSG and the signal analysis performed by the VSA are typically programmable so that signals of different frequency ranges, bandwidths, and signal modulation characteristics can be used to test whether various devices follow various wireless technology standards.

The calibration of the device under test (DUT) and the performance verification test are typically performed using a conductive signal path, such as an RF cable, rather than using a wireless signal path through which the device under test (DUT) communicates with the tester via electromagnetic radiation. Accordingly, the signal between the tester and the device under test (DUT) is carried via the conductive signal path rather than radiating outward through the surrounding space. The use of these conductive signal paths helps ensure repeatability and consistency of the measurements, and eliminates the need to consider the positioning and orientation of the device under test (DUT) in signal loading (transmission and reception).

For a multiple input multiple output (MIMO) device under test (DUT), each input/output connection of the device under test (DUT) must provide a certain type of signal path. For example, for a MIMO device intended to operate with three antennas, three conductive signal paths must be provided, for example, Cables and connections for testing.

However, the use of a conductive signal path significantly affects the time required to test each device under test (DUT) due to the need to physically connect and disconnect the cable between the device under test (DUT) and the tester. Moreover, for a MIMO device under test (DUT), multiple such connections and disconnections are required at the beginning of the test and termination of the test. Moreover, since the signal carried during the test is not transmitted via ambient space (the manner in which the signal should be used for normal purposes), and the antenna of the device under test (DUT) is not used during the tests. Therefore, these tests did not simulate real-world operations, and the test results did not reflect any performance characteristics belonging to the antenna.

An alternative is to test using a test signal carried via electromagnetic radiation rather than electrically conducted via a cable. This method has the advantage of not requiring connection and disconnection of the test cable, thereby shortening the test time associated with the connection and disconnection. However, due to the electromagnetic signals originating from other places and scattered around the surrounding space, the "channel" of the radiated signal and the receiver antenna (that is, the surrounding space through which the radiation is received and received) is inherently susceptible to signal interference and errors. . The signals will be received by the device under test (DUT) antenna and may include multipath signals from various sources of interference due to signal reflection. Accordingly, the "conditions" of the "channel" are generally poor compared to the use of individual conductive signal paths (e.g., cables) for each antenna connection.

One method of preventing or at least significantly reducing interference from such external signals is to use a shielded enclosure to isolate the radiation signal interface of the device under test (DUT) and the tester. However, such enclosures typically do not produce comparable measurement accuracy and repeatability. In particular, it is smaller than the outer casing of the smallest echo-free chamber. Moreover, the enclosures are typically sensitive to the location and orientation of the device under test (DUT) and are also sensitive to constructive and destructive interference of multipath signals generated within such enclosures.

Accordingly, it would be desirable to have systems and methods for testing wireless signal transceivers, particularly wireless MIMO signal transceivers, in which radiated electromagnetic test signals can be used to simulate real world system operation and to avoid connecting and disconnecting test cables. The required test time while maintaining test repeatability and accuracy by avoiding interfering signals due to externally generated signals and multipath signal effects.

In accordance with the present invention, a method of facilitating wireless testing of a multiple radio frequency (RF) signal transceiver device under test (DUT) is provided. Maximum radiation can be maximized by controlling the individual signal phases of multiple radio frequency (RF) test signals radiated to the device under test (DUT) using multiple antennas within a shielded enclosure containing the device under test (DUT) The direct-coupled signal of the target device under test (DUT) while minimizing the cross-coupled signal. Furthermore, the direct-coupled signal radiated to its individual target device under test (DUT) can be normalized by controlling the individual signal magnitude of the radio frequency (RF) test signal radiated to the device under test (DUT). At the same time, it is still sufficient to reduce the cross-coupling signal. Thus, compensation for the multipath signal environment within the shielded enclosure is provided, thereby simulating a wired test signal path in a wireless test of the device under test (DUT).

In accordance with an embodiment of the present invention, a method of facilitating wireless testing of a multiple radio frequency (RF) signal transceiver device under test (DUT) includes providing a phase having at least first and second wired radio frequency (RF) test signals At least first and second wired radio frequency (RF) test signals; controlling the at least first and second wired radio frequency (RF) test signal phases to provide corresponding at least first and second controlled radio frequency (RF) signals; Transmitting the at least first and second respectively received by at least first and second devices under test (DUTs) disposed within the interior region via a plurality of antennas disposed at least partially within an interior region of a structure a controlled radio frequency (RF) signal, wherein the structure defines the inner region and an outer region and is configured to substantially isolate the inner region from electromagnetic radiation originating from the outer region; accepting from the at least first and second measured Corresponding at least first and second signals of the device (DUT) respectively indicating at least one or more of the first controlled radio frequency (RF) signals received by the first device under test (DUT) a first power level of the signal and a second power level of the one or more signals not associated with the first controlled radio frequency (RF) signal, and received by the second device under test (DUT) a third power level associated with one or more signals of the second controlled radio frequency (RF) signal and a fourth power level of one or more signals not related to the second controlled radio frequency (RF) signal Level; and repeating the at least first and second wired radio frequency (RF) tests The control number of phases, until the first and the third power level exceeds the third and fourth power level reaches a minimum.

In accordance with another embodiment of the present invention, a method of facilitating wireless testing of a multiple radio frequency (RF) signal transceiver device under test (DUT) includes providing a corresponding at least first and second wired radio frequency (RF) test signals At least first and second wired radio frequency (RF) test signals of the phase; controlling the at least first and second wired radio frequency (RF) test signal phases to provide corresponding at least first and second controlled radio frequency (RF) signals Transmitting, by the plurality of antennas at least partially disposed within an interior region of a structure, respectively, by the at least first and second devices under test (DUTs) disposed within the interior region First and second controlled radio frequency (RF) signals, wherein the structure defines the inner region and an outer region and is configured to substantially isolate the inner region from electromagnetic radiation originating from the outer region, and the plurality of antennas Forming at least a portion of a wireless communication channel with at least a portion of the internal region, via the wireless communication channel, at least first and second associated with the at least first and second controlled radio frequency (RF) signals, respectively A plurality of controlled radio frequency (RF) signal components are propagated for reception by the at least first and second devices under test (DUT); receiving at least corresponding ones from the at least first and second devices under test (DUT) And a second signal respectively indicating, at least, a first power level of the first plurality of controlled radio frequency (RF) signal components received by the first device under test (DUT) different from the first a second power level of a plurality of controlled radio frequency (RF) signal components of the plurality of controlled radio frequency (RF) signal components, and the second plurality of controlled ones received by the second device under test (DUT) A third power level of the radio frequency (RF) signal component is different from a fourth power level of another plurality of controlled radio frequency (RF) signal components of the second plurality of controlled radio frequency (RF) signal components; and repeating the at least first and second wired radio frequency (RF) test signals The control of the phase until the first and third power levels exceed the third and fourth power levels by a minimum amount.

In accordance with another embodiment of the present invention, a method of facilitating wireless testing of a multiple radio frequency (RF) signal transceiver device under test (DUT) includes providing a radio frequency (RF) having corresponding at least first and second wires Testing at least first and second wired radio frequency (RF) test signals of the signal phase; controlling the at least first and second wired radio frequency (RF) test signal phases to provide corresponding at least First and second controlled radio frequency (RF) signals; transmitted via at least a first plurality of antennas disposed at least partially within an interior region of a structure by at least first and second devices under test disposed within the interior region ( The at least first and second controlled radio frequency (RF) signals received by the DUT, wherein the structure defines the inner region and an outer region and is configured to substantially isolate the inner region from electromagnetic radiation originating from the outer region And the plurality of antennas and at least a portion of the internal area jointly define at least a portion of a wireless communication channel, characterized by having a wireless communication channel matrix H of a plurality of wireless communication channel coefficients hij, the plurality of wireless communications The channel coefficients include direct-coupling coefficients (where i=j) and cross-coupling coefficients (where i≠j); accepting at least first and second signals from the at least first and second devices under test (DUT) Determining at least a first of the at least first and second controlled radio frequency (RF) signals received by the at least first and second devices under test (DUT) and related to the plurality of wireless communication channel coefficients With the second work Level; and repeating at least the first phase of the control signal (RF) testing a second RF cable, until the plurality of direct - coupling coefficient higher than those of the cross - coupling coefficient reaches a minimum.

10‧‧‧ Controller

11a, 11b‧‧‧Wired signal interface

20‧‧‧ diagonal matrix

20a‧‧‧Matrix

22‧‧‧ diagonal

24a, 24b‧‧‧cross-coupling coefficient

100‧‧‧Tester

100a‧‧‧Tester

102‧‧‧Antenna

102a, 102b, 102n‧‧‧ tester antenna

102aa, 102ab, 102am, 102ba, 102bm‧‧‧ antenna elements

103a‧‧‧RF (RF) test signal

103ai‧‧‧main incident signal component

103aa, 103ab, 103am, 103bb, 103ba‧‧‧ signals

103br,103cr‧‧‧reflected signal component

104‧‧‧Conductive signal connector

104a, 104b, 104n‧‧‧ tester connector

105a, 105b, 105n‧‧‧ test signals

106‧‧‧RF (RF) coaxial cable

106a, 106b, 106n‧‧‧ test cable

107‧‧‧Test connection

107a‧‧ Channel

110, 110a, 110b, 110n‧‧‧ signal source

111, 111a, 111b, 111n‧‧‧ radio frequency (RF) test signals

130,130a,130b‧‧‧RF signal control circuit

131aa, 131ab, 131am‧‧‧ radio frequency (RF) test signals

132‧‧‧Signal size control circuit

133‧‧‧ test signal

135a, 135b, 135m‧‧‧ radio frequency (RF) test signal

136, 136a, 136b, 136m‧‧‧ phase control circuit

137,138‧‧‧Control circuit

139a, 139b, 139m‧‧‧ control signals

150‧‧‧ Radio Frequency (RF) Signal Control Circuit

152‧‧‧ Circuitry

152a, 152b‧‧‧ phase control components

155a‧‧‧ feedback signal

155b‧‧‧ signal

200,200a‧‧‧Device under test (DUT)

201a, 201aa‧‧‧Reward information

202,202a,202b,202n‧‧‧Antenna

203‧‧‧radiating electromagnetic signals/signals

203a‧‧‧Device under test (DUT) signal

203b, 203c‧‧‧ signal components

203br, 203cr‧‧‧ reflected signal component

203ai‧‧‧main incident signal component

203i‧‧‧incident signal component

203r‧‧‧reflected signal component

204‧‧‧Conductive signal connector

204a, 204b, 204n‧‧‧Device under test (DUT) connector

207ap, 207bp‧‧‧ phase control signal

210, 210a, 210b, 210n‧‧‧ Radio Frequency (RF) Signal Receiver

211‧‧‧Communication test signal

211a, 211b, 211n‧‧‧ radio frequency (RF) test signals

300,300b‧‧‧Shielded enclosure

301‧‧‧Internal

301a, 301b‧‧‧Internal area

301d‧‧‧ end face

302,304,306‧‧‧Internal surface

320‧‧‧ Radio Frequency (RF) Absorbent Materials

232, 232a, 232b‧‧‧ control signal gain stage

234‧‧‧Signal combining circuit

235‧‧‧Complex test signal

235a, 235b‧‧‧ antenna array

236a, 236b, 236c, 236d, 236e, 236g, 236h, 236i, 236j, 236k, 236l, 236m, 236n, 236o, 236p ‧ ‧ phase control circuit

237a, 237b, 237n‧‧‧ phase-controlled test signals

242‧‧‧Control system

242b‧‧‧Control circuit

242aa, 242ab, 242an, 243aa, 243ab, 243an‧‧‧ power measurement signals

242ca, 242cb, 242cn‧‧‧ phase detector

242d‧‧‧Control circuit

243a, 243b, 243n‧‧‧ power measurement signals

243ba, 243bb, 243bn‧‧‧ phase control signals

243ca, 243cb, 243cn‧‧‧ phase data

243da, 243dn, 243db‧‧‧ phase control signal

244‧‧‧Replacement of downstream control systems

244a‧‧‧Power measurement circuit

244b‧‧‧Control circuit

245a, 245b, 245n, 245ba, 245bb, 245bn‧‧‧ phase control signals

410,420,430,440‧‧‧Process

411,412,413,414,415,416,417,418,421,422,423,424,425,426,427,431,432,433,434,435,441,442,443,444,445,446,447,448,449,450,451‧‧

510‧‧‧Expanded

511‧‧‧frequency band

521‧‧‧ upper map

522, 523‧‧‧ response map

H11, h22, hnn‧‧ channel

H11, h12, h22, h21, h1n, h2n, hn1, hn2‧‧ channel

Figure 1 depicts a typical operation of a wireless signal transceiver and a possible test environment.

Figure 2 depicts a wireless signal transceiver test environment using a conductive test signal path.

Figure 3 depicts a MIMO wireless signal transceiver test environment using a conductive signal path and The channel model for these test environments.

4 depicts a MIMO wireless signal transceiver test environment using radiated electromagnetic signals and a channel model for such test environments.

FIG. 5 depicts a test environment in which an MIMO device under test (DUT) can be tested using a radiated electromagnetic test signal in accordance with an exemplary embodiment.

Figure 6 depicts a test environment where a device under test (DUT) is tested using a radiated electromagnetic test signal within a shielded enclosure.

7 and 8 depict an exemplary embodiment of a test environment for testing a wireless device under test (DUT) using a radiated electromagnetic test signal within a shielded enclosure that reduces multipath signal effects.

Figure 9 depicts a physical representation of a shielded enclosure in accordance with an exemplary embodiment for use in the test environment of Figures 7 and 8.

10 depicts a test environment in which a device under test (DUT) can be tested using a radiated electromagnetic test signal, in accordance with an illustrative embodiment.

11 depicts another test environment in which a device under test (DUT) can be tested using a radiated electromagnetic test signal, in accordance with an illustrative embodiment.

Figure 12 depicts an exemplary algorithm for testing a device under test (DUT) using the test environment of Figure 11.

13 depicts another test environment in which a device under test (DUT) can be tested using a radiated electromagnetic test signal, in accordance with an illustrative embodiment.

Figure 14 depicts an exemplary algorithm for testing a device under test (DUT) using the test environment of Figure 13.

Figure 15 depicts another test environment in which radiation electromagnetic can be used in accordance with an illustrative embodiment The test signal tests a device under test (DUT).

Figure 16 depicts an exemplary algorithm for testing a device under test (DUT) using the test environment of Figure 15.

17 depicts a test signal transmitted over a defined frequency range by a device under test (DUT) prior to compensation, in accordance with an exemplary embodiment.

18 depicts the scan test signal of FIG. 17 before and after compensation, and the exemplary phase shift values of the test environment of FIGS. 10, 11, 13, and 15 in accordance with an exemplary embodiment.

Figure 19 depicts an exemplary algorithm for performing the compensation as described in Figure 18.

20 depicts another test environment for testing one wireless device under test (DUT) using multiple test signal phase shifts in accordance with an exemplary embodiment.

21 depicts the test environment of FIG. 20 with additional test signal gain adjustments for compensation, in accordance with an additional exemplary embodiment.

The following illustrative embodiments of the invention are described in detail with reference to the drawings. The description is intended to be illustrative, and not to limit the scope of the invention. The embodiments are described in sufficient detail to enable those of ordinary skill in the art to practice the invention. It is understood that other embodiments may be practiced without departing from the spirit and scope of the invention.

Throughout the disclosure, it is to be understood that the various circuit elements described may be singular or plural in number. For example, the terms "circuit" and "circuitry" may include a single element or a plurality of elements, which may be active and/or passive, and connected or otherwise coupled together (for example , such as the same or a plurality of complexes Circuit wafers) to provide the described functionality. In addition, the "signal" can refer to one or more currents, one or more voltages or data signals. In the drawings, similar or related elements may have similar or related alphanumeric or alphanumeric identifiers. Furthermore, although the invention has been discussed using discrete electronic circuitry (preferably in the form of one or a plurality of integrated circuit wafers), it may additionally be used depending on the frequency or data rate of the signal to be processed. One or more suitably programmed processors implement the functionality of any of the circuitry. Moreover, in the case of graphically illustrating functional block diagrams of various embodiments, the functional blocks are not necessarily indicative of the blocks between the hardware circuitry.

Please refer to FIG. 1, a typical operating environment of a wireless signal transceiver and an ideal test environment (at least in terms of simulating real world operation) with a tester 100 and a device under test (DUT) 200 for wireless communication. Typically, some form of test controller 10 (e.g., a personal computer) will also be used to exchange test commands and data with tester 100 and device under test (DUT) 200 via wired signal interfaces 11a, 11b. Tester 100 and device under test (DUT) 200 each have one (for MIMO devices, multiple) respective antennas 102, 202 that are connected by conductive signal connectors 104, 204 (eg, coaxial cable connections, Many types are well known in the art). Test signals (sources and responses) are wirelessly carried between the tester 100 and the device under test (DUT) 200 via antennas 102, 202. For example, during a transmission (TX) test of the device under test (DUT) 200, the device under test (DUT) antenna 202 will radiate an electromagnetic signal 203. Depending on the directionality of the antenna transmit pattern, this signal 203 will radiate in many directions, causing the tester antenna 102 to receive the incident signal component 203i and the reflected signal component 203r. As described above, these reflected signal components 203r, which are typically multipath signal effects and products derived from electromagnetic signals elsewhere (not shown), cause constructive and destructive signal interference, thereby impeding reliability and Repeated signal reception and test results.

Referring to FIG. 2, in order to avoid such unreliable test results, a conductive signal path (such as a radio frequency (RF) coaxial cable 106) is used to connect the tester 100 and the antenna connectors 104, 204 of the device under test (DUT) 200, A test signal is carried to provide a consistent, reliable, and repeatable conductive signal path between the tester 100 and the device under test (DUT) 200. As noted above, however, the time required to connect and disconnect the cable 106 before and after testing can extend the overall test time.

Referring to FIG. 3, when testing the MIMO device under test (DUT) 200a, the additional test time for connecting and disconnecting the test cable becomes even longer. In such cases, multiple test cables 106 are required to connect the corresponding tester connector 104 and device under test (DUT) connector 204 to enable carrying radio frequency (RF) signal sources from within tester 100a. A radio frequency (RF) test signal of 110 (e.g., VSG) is received by a radio frequency (RF) signal receiver 210 within the device under test (DUT) 200a. For example, in a typical test environment, a tester for testing a MIMO device will have one or more VSGs 110a, 110b, ..., 110n to provide a corresponding one or more radio frequency (RF) test signals 111a. , 111b, ..., 111n (eg, packet data signals with variable signal power, packet content, and data rate). The corresponding test cables 106a, 106b, ..., 106n are connected by respective tester connectors 104a, 104b, ..., 104n and device under test (DUT) connectors 204a, 204b, ..., 204n. These signals are sent to provide received radio frequency (RF) test signals 211a, 211b, ..., 211n to corresponding radio frequency (RF) signal receivers 210a, 210b, ..., 210n within the device under test (DUT) 200a. Accordingly, the additional test time required to connect and disconnect these test cables 106 can be increased by a factor of n, which corresponds to the number of test cables 106.

As described above, the use of test cables to connect tester 100a and device under test (DUT) 200a does have the advantage of providing consistent, reliable, and repeatable test connections. As is known to those skilled in the art, the test connections 107 can be modeled as a signal channel H characterized by a pair of angular matrices 20, wherein the diagonal matrix elements 22 correspond to channel characteristics for the individual signals (eg, The direct-coupling coefficients h ₁₁ , h ₂₂ , . . . , h _nn (h _ij , where i=j) of the signal path conductance or loss of the individual test cable 106.

Referring to FIG. 4, in accordance with one or more exemplary embodiments, a conductive (or wired) channel 107 is replaced by a wireless channel 107a corresponding to the wireless signal interface 106a between the tester 100a and the device under test (DUT) 200a (FIG. 3). ). As described above, tester 100a and device under test (DUT) 200a communicate test signals 111, 211 via respective arrays of antennas 102, 202. In this type of test environment, the pair of angular matrices 20 are not used to represent the signal channel 107a, but the diagonal 22 is removed using one or more non-zero cross-coupling coefficients 24a, 24b (h _ij , where i ≠ j) A matrix 20a represents the signal channel 107a. It will be readily apparent to those skilled in the art that this is due to the plurality of available wireless signal paths in channel 107a. For example, unlike cable signal environments, each of the device under test (DUT) connectors 204 desirably receives only signals from its corresponding tester connector 104. In this wireless channel 107a, a first device under test (DUT) antenna 202a receives test signals radiated by all of the tester antennas 102a, 102b, ..., 102n, for example, corresponding to channel matrix H coefficients h ₁₁ , h ₁₂ , ... And h _1n .

According to conventional principles, the coefficient h of the channel matrix H corresponds to the characteristics of the channel 107a, which affects the transmission and reception of radio frequency (RF) test signals. These coefficients h jointly define the channel condition number k(H), which is the product of the norm of the H matrix and the norm of the inverse matrix of H, as expressed by the following equation: k(H)=| | H | | * | | H ^-1 | |

Factors affecting these coefficients change the number of channel conditions, causing measurement errors. For example, in a poorly qualified channel, small errors can cause large errors in the test results. In the case of a low number of channels, small errors in the channel can produce small measurement errors at the receiving (RX) antenna. However, in the case where the number of channels is high, a small error in the channel can cause a large measurement error at the receiving antenna. This channel condition number k(H) is also sensitive to the location and orientation of the physical device under test (DUT) within its test environment (eg, shielded enclosure) and the orientation of its various antennas 204. Accordingly, even if there is no external interference signal originating from other places or re-incident to the receiving antenna 204 via reflection, the possibility of repeating the accurate test result is still low.

Referring to FIG. 5, in accordance with one or more exemplary embodiments, the test signal interface between the tester 100a and the device under test (DUT) 200a may be wireless. A device under test (DUT) 200a is disposed within the interior 301 of the shielded enclosure 300. The shielded outer casing 300 can be implemented as a metal outer casing, for example, constructed or at least similar in effectiveness to a Faraday cage. This isolates the device under test (DUT) 200a from radiation signals originating from the outer region 302 of the outer casing 300. According to an exemplary embodiment, the geometry of the outer casing 300 is such that it acts as a closed waveguide.

Elsewhere, for example, a plurality of (n) antenna arrays 102a, 102b, ..., 102n are disposed within or on the opposite inner surface 302 of the outer casing 300, each of which radiates a test signal originating from the tester 100a A plurality of phase controlled radio frequency (RF) test signals 103a, 103b, ..., 103n of sources 110a, 110b, ..., 110n (discussed in more detail below). Each antenna array includes a plurality of (M) antenna elements. For example, the first antenna array 102a includes m antenna elements 102aa, 102ab, ..., 102am. These antenna elements are driven by respective phase-controlled radio frequency (RF) test signals 131aa, 131ab, ..., 131am provided by respective radio frequency (RF) signal control circuits 130a. Each of 102aa, 102ab, ..., 102am.

As described in the example of the first radio frequency (RF) signal control circuit 130a, the size of the radio frequency (RF) test signal 111a from the first radio frequency (RF) test signal source 110a is increased by the signal size control circuit 132 (eg, Zoom in) or decrease (for example, attenuate). The resulting size controlled test signal 133 is replicated by a signal replica circuit 134 (e.g., a signal divider). The respective signal phases of the formed size-controlled, replicated radio frequency (RF) test signals 135a, 135b, ..., 135m are controlled (e.g., shifted) by respective phase control circuits 136a, 136b, ..., 136m to The size and phase controlled signals 131aa, 131ab, ..., 131am are generated to drive the antenna elements 102aa, 102ab, ..., 102am of the antenna array 102a.

The remaining antenna arrays 102b, ..., 102n and their respective antenna elements are driven in a similar manner by corresponding radio frequency (RF) signal control circuits 130b, ..., 130m. This produces a corresponding number of composite radiated signals 103a, 103b, ..., 103n according to the channel matrix H as described above for carrying to the antennas 202a, 202b, ..., 202n of the device under test (DUT) 200a and by Wait for reception. The device under test (DUT) 200a processes its corresponding received test signals 211a, 211b, ..., 211m and provides one or more feedback signals 201a indicative of the characteristics (e.g., size, relative phase, etc.) of the received signals. These feedback signals 201a are provided to control circuitry 138 within radio frequency (RF) signal control circuitry 130. The control circuit 138 provides control signals 137, 139a, 139b, ..., 139m to the size control circuit 132 and the phase control circuit 136. Accordingly, a closed loop control path is provided to gain and phase control the individual radiated signals from the tester 100a for reception by the device under test (DUT) 200a. (Alternatively, this control circuit 130 can be included as part of the tester 100a).

In accordance with conventional channel optimization techniques, control circuit 138 uses feedback material 201a from device under test (DUT) 200a in a manner similar to minimizing channel condition number k(H). The magnitude and phase of the radiated signal are varied to achieve optimal channel conditions and produce received signals of approximately equal magnitude as measured at each of the device under test (DUT) antennas 202. This will establish a communication channel through which the radiation signal produces a test result that substantially rivals the test results produced using a conductive signal path (eg, a radio frequency (RF) signal cable).

After successive transmission and channel condition feedback events, this operation of the control circuit 138 of the radio frequency (RF) signal control circuit 130 will change the signal size and phase of each of the antenna arrays 102a, 102b, ..., 102n to achieve the most The number of channel conditions of Jiahua is k(H). Once the optimized channel condition number k(H) has been achieved, the corresponding size and phase settings can be retained, and the tester 100a and the device under test (DUT) 200a can continue the subsequent test sequence as if on the cable The test environment does the same.

In practice, a reference device under test (DUT) can be placed in a test fixture within the shielded enclosure 300 for optimizing channel conditions through the repeated procedures described above. Thereafter, other devices under test (DUTs) of the same design can be tested in succession without having to perform channel optimization each time, since the path loss experienced in the controlled channel environment of the enclosure 300 should be Within normal test tolerances.

Still referring to FIG. 5, for example, the model is initially transmitted to generate a channel condition number of 13.8 db, and the magnitudes of the h ₁₁ and h ₂₂ coefficients are -28 db and -28.5 db, respectively. The size matrix of channel H will be expressed as follows:

After resizing and phase repeatedly as described above, the channel condition number k(H) is reduced to 2.27 db, and the h ₁₁ and h ₂₂ coefficients are -0.12 db and -0.18 db, respectively, and the following channel size matrix is generated:

These results are comparable to the results of using a cable test environment, indicating that this wireless test environment provides comparable accuracy. Eliminating the time to connect and disconnect the signal path of the cable, and including the shortening of gain and phase adjustment, the overall received signal test time is significantly shortened.

Please refer to Figure 6 for a better understanding of the effects of multipath signal effects on channel conditions. As described above, once the device under test (DUT) 200a is placed within the interior 301 of the housing 300, the device under test (DUT) 200a will radiate the electromagnetic signal 203a from each antenna 202a during the transmission test. This signal 203a contains components 203b, 203c that are radiating outwardly and away from the antenna 102a of the tester 100a. However, these signal components 203b, 203c are reflected off the inner surfaces 304, 306 of the outer casing 300 and are incident as reflected signal components 203br, 203cr, and constructively or destructively combined with the main incident signal component 203ai in accordance with multipath signal conditions. . As noted above, depending on the constructive and destructive nature of the interference, test results are often not reliably and accurately used in proper calibration and performance verification.

Referring to FIG. 7, a radio frequency (RF) absorber material is provided according to an exemplary embodiment. 320a, 320b are disposed at reflective surfaces 304, 306. As a result, the reflected signal components 203br, 203cr are significantly attenuated, resulting in less constructive or destructive interference to the primary incident signal component 203ai.

Additional radio frequency (RF) signal control circuitry 150 may be included for use between antenna array 102a and tester 100a, which is mounted within or on interior surface 301 of housing 300a. (Alternatively, this additional control circuit 150 can be included as part of the tester 100a). The radiation signals incident on the antenna elements 102aa, 102ab, ..., 102am produce received signals 103aa, 103ab, ..., 103am, wherein the respective signal phases are controlled (e.g., shifted) by the phase control circuit 152, the phase Control circuit 152 controls phase control elements 152a, 152b, ..., 152m in accordance with one or more phase control signals 157a, 157b, ..., 157m provided by control system 156. The resulting phase controlled signals 153 are combined in a signal combiner 154 to provide the received signal 155a to the tester 100a and a feedback signal 155b to the control system 156. Control system 156, which is part of a closed loop control network, processes this feedback signal 155b to adjust the respective phases of composite received signals 103aa, 103ab, ..., 103am as needed to minimize the internal region 301 associated with housing 300a. Apparent signal path loss. In the case of changing the position and orientation of the device under test (DUT) 200a within the housing 300a, the closed-loop control network also allows the system to reconfigure the phased array enabled by the antennas 102a and phase control circuit 152. As a result, after minimizing the path loss using this feedback loop, it is achieved that the device under test (DUT) signal 203a to the tester 100a is accurately and reproducibly carried within the housing 300a using the radiated signal environment.

Referring to Figure 8, similar control and improvement can be achieved for the device under test (DUT) to receive signal tests to produce accurate and repeatable test results. In this case, the test signal 111a provided by the tester 100a is reproduced by the signal combiner/splitter 154, and the respective phases of the copied test signal 153 are adjusted by the phase control circuit 152 as needed, and then by the antenna element 102aa. , 102ab, ..., 102am radiation. As in the foregoing case, the reflected signal components 103br, 103cr are significantly attenuated, resulting in less constructive or destructive interference to the primary incident signal component 103ai. One or more feedback signals 203a from the device under test (DUT) 200a provide information needed to control the phase of the replicated test signal 153 to the control system 156 to minimize the apparent signal path associated with the interior 301 of the housing 300a. Loss, thereby establishing a consistent and repeatable condition of signal path loss.

Referring to FIG. 9, in accordance with one or more exemplary embodiments, the shielded outer casing 300b can be implemented substantially as shown. As described above, the device under test (DUT) can be positioned at one end 301d of the inner portion 301 of the outer casing 300b, which is opposite the inner region 301b, which includes or faces the tester antenna arrays 102a, 102b, .. ., the inner surface 302 where 102n is located (Fig. 5). Located therebetween is an inner region 301a surrounded by a radio frequency (RF) absorber material 320.

As described above and with the following details, an exemplary embodiment of the system and method in accordance with the present invention enables cableless testing of a wireless device under test (DUT) while performing multipath effect compensation and optimized signal path loss control. Multiple antennas, and an antenna array, with a control system that can be used to adjust the phase of the test signal provided to the antenna element, emulating the stable and repeatable signal path loss typically associated with a conductive signal path environment Environment, using a radiation signal environment inside a shielded enclosure. At the same time, the time required to adjust the phase shifter is part of all of the overall test time, which is significantly less than the time required to connect and disconnect the test cable, and can provide realism including the antenna component Additional benefits of world testing.

Furthermore, as described above and in further detail below, exemplary embodiments of the present invention provide for the use of signals having a wide frequency bandwidth (eg, Electrical Engineering of Electrical Engineering (IEEE) standard 802.11ac). The cable-free test of the 160 megahertz (MHz) wide signal) wireless test device (DUT) can achieve the same test accuracy and measurement as the test signal path (such as test cable). Repeatability. The wideband signal received within the shielded test enclosure produces a substantially flat signal response by adjusting the phase of the test signal provided to the antenna element. Once the individual test signal phases that drive the individual antenna elements are adjusted to produce this flat signal response environment, the test using the wideband signals can be performed directly without further adjustments, as in a cabled test environment. While the location of the device under test (DUT) within the shielded enclosure can affect the flatness of the channel response, this location sensitivity is within the measurement tolerances described in the signal standard (eg, IEEE 802.11ac).

Moreover, according to an exemplary embodiment, the multiple test device (DUT) within the same shielded enclosure can perform this cableless test simultaneously. By properly controlling and adjusting the phase and magnitude of the test signal driving the multiple antenna elements, a radiation test signal environment within the shielded enclosure can be used to mimic the low crosstalk interference signal environment of the conducted signal path. Once the phase and gain (or attenuation) of the test signal driving the antenna element are adjusted in accordance with the exemplary embodiment, the signal received by the antenna of the multiple device under test (DUT) will be received using the cable signal path. The signal is equal. For example, this can be achieved by maximizing the direct-coupling coefficient of the channel matrix while minimizing the cross-coupling coefficients of the channel matrix (eg, producing a difference of at least 10 dB between the direct-and cross-coupling coefficients).

Referring to FIG. 10, in accordance with an exemplary embodiment, a device under test (DUT) 200a is located within the shielded enclosure 300 for transmitting signal testing. The test signal 203a transmitted via the antenna 202a of the device under test (DUT) is received by the multiple antenna elements 102a, 102b, ..., 102n. The individual signal phases of the generated received signals 105a, 105b, ..., 105n are determined by individual phases Control circuits 236a, 236b, ..., 236n control and adjustment.

According to some exemplary embodiments, the generated phase controlled test signals 237a, 237b, ..., 237n are sent to a control system 242 (described in further detail below) and signal combining circuit 234. The control system 242 provides phase control signals 243a, 243b, ..., 243n to the phase control circuits 236a, 236b, ..., 236n. The combined (e.g., summed) phase controlled test signals 237a, 237b, ..., 237n generate a composite test signal 235 for downstream analysis, such as a VSA (not shown).

According to other embodiments, phase controlled test signals 237a, 237b, ..., 237n are combined in signal combiner 234 to produce composite test signal 235. The composite test signal 235 is sent to an alternate control system 244 (described in further detail below) which then provides phase control signals 245a, 245b, ..., 245n to the phase control circuits 236a, 236b, ..., 236n.

Referring to Figure 11, in accordance with an exemplary embodiment, on-line control system 242 includes power measurement circuits 242aa, 242ab, ..., 242an for measuring individual power levels of phase-controlled test signals 237a, 237b, ..., 237n. The resulting power measurement signals 243aa, 243ab, ..., 243an indicative of individual test signal power levels are provided to control circuitry 242b (e.g., in the form of a digital signal processor (DSP)), which then provides appropriate phase control signals 243ba, 243bb, ..., 243bn are given to phase control circuits 236a, 236b, ..., 236n.

Referring to Figure 12, in accordance with an exemplary embodiment, the mode of operation 410 of the test environment of Figure 11 can be performed as shown. First, the phase shifters 236a, 236b, ..., 236n are initialized in step 411, for example, setting all phase shift values to a same reference phase value or individual reference phase values. Next, the power levels of the phase controlled signals 237a, 237b, ..., 237n are measured in step 412. Then, the measured power value is added in step 413, and the tired is compared in step 414. The measured signal power is compared to a previously accumulated measured signal power. In step 415, if the current cumulative measured power is higher than the previous accumulated measured power, the current phase shift value and the accumulated measured power are stored, and then the stored values are compared with the expected criterion (eg, one in step 416). Maximize cumulative measurement power). In step 417, if the criterion is met, the adjustment of the phase of the test signal is stopped. If not, continue to adjust the phase of the test signal.

Similarly, in step 414, if the current accumulated measured power is not higher than the previous accumulated measured power, the test signal is continuously adjusted. Therefore, in step 418, the phase shifters 236a, 236b, ..., 236n are adjusted according to, for example, a genetic algorithm (GA) or a particle swarm optimization algorithm (PSA) to give received test signals 105a, 105b, ..., 105n A combination or permutation of another phase shift value. After this step, the power measurement 412 is repeated, summed 413 and compared 414 until the desired criterion is met.

Referring to Figure 13, in accordance with another exemplary embodiment, the alternate downstream control system 244 (Figure 10) includes a power measurement circuit 244a (e.g., a VSA) and a control circuit 244b (e.g., a digital signal processor (a DSP) ). The power level of the composite signal 235 is measured by the power measurement circuit 244a to provide power measurement data 245a to the control circuit 244b. Control circuit 244b then provides appropriate phase control signals 245ba, 245bb, ..., 245bn to phase shifters 236a, 236b, ..., 236n.

Referring to Figure 14, the mode of operation 420 of the test environment as shown in Figure 13 can be performed as shown. First, in step 421, phase shifters 236a, 236b, ..., 236n are initialized by setting one or more individual phase shift values in advance. Next, in step 422, the power level of the composite signal 235 is measured, and then in step 423, the current measured power and a previously measured power level are compared. In step 424, if the current measured power level is higher than the previous measured power level, The current phase shift value and the measured power are then stored and used in step 425 to determine if the desired criterion has been met (eg, a maximized measured power level). In step 426, if the desired criterion is met, the phase adjustment is stopped. If the desired criterion is not met, the phase is continuously adjusted.

Similarly, if the current measured power is not higher than the previously measured power, the phase is continuously adjusted. Thus, phase shifters 236a, 236b, ..., 236n are adjusted according to an optimization algorithm (e.g., a GA or PSA) to give another set of phase shift values for receiving test signals 105a, 105b, ..., 105n.

Referring to Figure 15, in accordance with another exemplary embodiment, the in-line system 242 (Figure 10) includes phase detection circuits 242ca, 242cb, ..., 242cn and control circuitry 242d (e.g., a DSP). The phase detectors 242ca, 242cb, ..., 242cn can detect the individual signal phases of the phase controlled signals 237a, 237b, ..., 237n and provide corresponding phase data 243ca, 243cb, ..., 243cn to the control circuit 242d. Based on this information, control circuit 242d provides appropriate phase control signals 243da, 243db, ..., 243dn to phase shifters 236a, 236b, ..., 236n.

Referring to Figure 16, the mode of operation 430 of the test environment as in Figure 15 can be performed as shown. First, in step 431, phase shifters 236a, 236b..., 236n are initialized by giving one or more individual phase shift values. Next, in step 432, the individual phases of the phase controlled signals 237a, 237b, ... 237n are measured (e.g., relative to an identical or reference signal phase).

Next, based on the measured test signal phase, the phase adjustment of the phase shifters 236a, 236b, ..., 236n is configured in accordance with the optimized phase shift value in step 433. After this step, in step 434, the power level of the composite signal 235 is measured to confirm that the desired composite signal power level is reached, and then the phase adjustment is stopped in step 435.

Referring to Figure 17, a broadband day from a constant power device (DUT) 200a The exemplary received signal 203 emitted by line 202a radiates a good response in the frequency range of 700 to 6000 MHz within shielded enclosure 300 (e.g., Figure 6), as substantially shown in the figure. It can be clearly understood that the power profile is not flat based on the rich multipath signal environment within the shielded enclosure 300. For example, a packet data signal that communicates according to the IEEE standard 802.11ac is used, with a particular focus on a 160 MHz wide frequency band between 5000 and 5160 MHz. As shown, within this frequency band 511 (as indicated by the enlarged portion 510 of the signal 203 profile), the received signal exhibits a power variation of approximately 25 decibels (dB). According to an exemplary embodiment, using the test environment as described above and using a multiple phase shifter to control the phase of the test signal used to drive the multiple antenna elements, the present map may be compensated such that the focused frequency band 511 is substantially flat.

Referring to FIG. 18, this object can be achieved by using multiple (e.g., 16) antenna elements 102 and corresponding phase shifters 236, in accordance with an exemplary embodiment. For example, an optimized flat response condition 523 may be achieved by using an optimization algorithm (further detailed below) and using only quadrature phase adjustments of 0, 90, 180, and 270 degrees. As shown, the response profile 522 has a variation of more than 5 dB between the 160 MHz bandwidth 511 of the exemplary test signal prior to compensation. Moreover, even if the antenna array has been optimized for power level at a frequency midpoint of 5080 MHz, as shown in the upper profile 521, the variation of the received signal is still about 5 decibels. However, when the multiple phase adjusters 236a, 236b, ..., 236p are appropriately adjusted, even if only the quadrature phase adjustment is limited, it is possible to achieve a response profile 523 having a variation of not more than 0.5 decibels.

Referring to Figure 19, the compensation shown in Figure 18 can be achieved by using the illustrated flow 440. First, in step 441, a plurality of frequency values within the desired signal bandwidth are defined, and in step 442, a set of initial phase shift values for the phase shifter is defined. In step 443, the phase shifter is set using the defined phase value, and in step 444, each frequency is measured. Rate of power. Next, in step 445, the difference between the measured powers of the plurality of pairs of defined frequencies is calculated, and in step 446, the sum is used to evaluate a function F which is equal to between the defined maximum power difference and the calculated power plus total difference. The difference.

If the current calculation function F is greater than a previous operation of _{the current} function of _{the old F,} the phase shifter is retained values in Step 448, and the decision in step 449 satisfies a desired condition (e.g., to achieve a maximization operation function F ). If so, the phase adjustment is stopped at step 450. If the desired criterion is not met, the phase is continuously adjusted. Similarly, if the current calculation function F is not greater than a previous operation of _{the current} function of _{the old} F, continue adjusting the phase. In step 451, the phase is further adjusted by defining another set of values of the phase shifter values, and the phase adjustment step 443, the measurement power step 444, the operational power difference step 445, and the evaluation of the operational function F step 446 are repeated. . This process is repeated until the condition is met in step 449.

Referring to FIG. 20, similar compensation can be achieved using a cross-coupled signal within the shielded enclosure 300 when cableless testing of multiple wireless devices under test (DUT) is performed, in accordance with an exemplary embodiment. (For the purposes of this example, two antenna arrays 235a, 235b are used to test the two devices under test (DUT) 200a, 200b. However, it is clear that other numbers of devices under test (DUT) and antenna arrays can be used. Furthermore, it should be clearly understood that the respective "device under test (DUT)" 200a, 200b described herein can be an individual receiver within a single MIMO device (DUT) 200.) As described above, the signal A source (e.g., VSG) 110 can provide a test signal 111 and replicate with signal distributor 234 to provide a copy of test signal 235 for phase shifting by multiple phase shifter 231 to drive the antenna array 235. Antenna element 102. The antenna arrays 235a, 235b provide radiated signal components 103aa, 103ab, 103ba, 103bb that correspond to direct-coupling and cross-coupling coefficients of the channel matrix H (eg, as described above). The signal points The quantities 103aa, 103ab, 103ba, 103bb are received by the antennas 202a, 202b of the devices under test (DUT) 200a, 200b. The received signal data 201a, 201b is provided by the device under test (DUT) 200a, 200b to a control system 206 (e.g., a DSP), which then provides appropriate phase control signals 207ap, 207bp to phase shifters 236aa, ..., 236am, 236ba. , ..., 236bm, for controlling the phase of the signal radiated by the antenna elements 102aa, ..., 102am, 102ba, ... 102bm of the antenna arrays 235a, 235b.

By repeatedly adjusting the phase of the radiated signal, as described above, the direct-coupled channel matrix H coefficients 103aa, 103ba can be maximized and minimized by the cross-coupling coefficients 103ab, 103bb (eg, by making the final crossover - The coupling coefficient desirably becomes at least 10 dB below the direct-coupling coefficient).

Referring to Figure 21, in accordance with another exemplary embodiment, control system 206 can be further configured to provide gain control signals 207ag, 207bg to control the size of the replicated test signals 111a, 111b for transmission to the device under test (DUT) 200a, 200b. Control signal gain stages (e.g., variation gain amplifiers or signal attenuators) 232a, 232b can control the signal sizes. It may be advantageous to further optimize the relative size of the direct-coupling coefficients 103aa, 103ba and the cross-coupling coefficients 103ab, 103bb of the channel matrix H. For example, the size of the direct-coupling coefficients 103aa, 103ba can be normalized while still retaining sufficient cross-coupling coefficients 103ab, 103bb attenuation (eg, 10 decibels or higher).

Various other modifications and alterations of the present invention will be apparent to those skilled in the art without departing from the scope of the invention. Although the present invention has been described in terms of specific preferred embodiments, it should be understood that the invention should not be I intend to define the invention in the scope of the following patent application. The scope and the structures and methods within the scope of the application are intended to cover the equivalent of the structures and methods.

Claims (6)

A method of facilitating wireless testing of a multiple radio frequency (RF) signal transceiver device under test (DUT), comprising: providing at least first and second wires having corresponding phase of at least first and second wired radio frequency (RF) test signals a radio frequency (RF) test signal; controlling the at least first and second wired radio frequency (RF) test signal phases to provide corresponding at least first and second controlled radio frequency (RF) signals; via at least partially disposed in a structure a plurality of antennas within an interior region transmitting the at least first and second controlled radio frequency (RF) signals respectively received by at least first and second devices under test (DUTs) disposed within the interior region Wherein the structure defines the inner region and an outer region and is configured to substantially isolate the inner region from electromagnetic radiation originating from the outer region; accepting at least corresponding correspondence from the at least first and second devices under test (DUT) First and second signals respectively indicating at least a first power level of one or more signals associated with the first controlled radio frequency (RF) signal received by the first device under test (DUT) And not related to the first a second power level of one or more signals of the radio frequency (RF) signal, and one or more of the second controlled radio frequency (RF) signals received by the second device under test (DUT) a third power level of the signal and a fourth power level of the one or more signals not related to the second controlled radio frequency (RF) signal; and repeating the at least first and second wired radio frequencies (RF) The control of the signal phase is controlled until the first and third power levels exceed the third and fourth power levels by a minimum amount. The method of claim 1, wherein: the at least first and second wired radio frequency (RF) test signals further have corresponding at least first and second wired radio frequency (RF) test signal sizes; and the method further comprises controlling The at least first and second wired radio frequency (RF) test signals are sized to provide the corresponding at least first and second controlled radio frequency (RF) signals, and to repeat the at least first and second wired radio frequency (RF) This control of the signal size is tested until the first and third power levels are approximately equal. A method of facilitating wireless testing of a multiple radio frequency (RF) signal transceiver device under test (DUT), comprising: providing at least first and second wires having corresponding phase of at least first and second wired radio frequency (RF) test signals a radio frequency (RF) test signal; controlling the at least first and second wired radio frequency (RF) test signal phases to provide corresponding at least first and second controlled radio frequency (RF) signals; via at least partially disposed in a structure a plurality of antennas within an interior region transmitting the at least first and second controlled radio frequency (RF) signals respectively received by at least first and second devices under test (DUTs) disposed within the interior region Wherein the structure defines the inner region and an outer region, and is configured to substantially isolate the inner region from electromagnetic radiation originating from the outer region, and the plurality of antennas and at least a portion of the inner region define a wireless communication channel At least a portion of the at least first and second plurality of controlled radio frequency (RF) signals associated with the at least first and second controlled radio frequency (RF) signals, respectively, via the wireless communication channel A quantity is propagated for receiving by the at least first and second devices under test (DUT); receiving at least first and second signals from the at least first and second devices under test (DUT), respectively Instructing: a first power level of the first plurality of controlled radio frequency (RF) signal components received by the first device under test (DUT) is different from the first plurality of controlled radio frequency (RF) signals a second power level of a plurality of components of the controlled radio frequency (RF) signal component, and a second plurality of controlled radio frequency (RF) signal components received by the second device under test (DUT) a third power level and a fourth power level of another plurality of controlled radio frequency (RF) signal components different from the second plurality of controlled radio frequency (RF) signal components; and repeating the at least first and The control of the phase of the two wired radio frequency (RF) test signals until the first and third power levels exceed the third and fourth power levels by a minimum amount. The method of claim 3, wherein: the at least first and second wired radio frequency (RF) test signals further have corresponding at least first and second wired radio frequency (RF) test signal sizes; and the method further comprises controlling The at least first and second wired radio frequency (RF) test signals are sized to provide the corresponding at least first and second controlled radio frequency (RF) signals, and to repeat the at least first and second wired radio frequency (RF) This control of the signal size is tested until the first and third power levels are approximately equal. A method of facilitating wireless testing of a multiple radio frequency (RF) signal transceiver device under test (DUT), comprising: providing at least first and second wires having corresponding phase of at least first and second wired radio frequency (RF) test signals a radio frequency (RF) test signal; controlling the at least first and second wired radio frequency (RF) test signal phases to provide corresponding at least first and second controlled radio frequency (RF) signals; via at least partially disposed in a structure a plurality of antennas within an interior region transmitting the at least first and second controlled radio frequency (RF) signals received by at least first and second devices under test (DUTs) disposed within the interior region, wherein The structure defines the inner region and an outer region and is configured to substantially isolate the inner region from electromagnetic radiation originating from the outer region, and the plurality of antennas together with at least a portion of the inner region define a wireless communication channel At least one portion is characterized by having a wireless communication channel matrix H of a plurality of wireless communication channel coefficients h _ij , the plurality of wireless communication channel coefficients including a direct-coupling coefficient (where i=j) and the intersection- a coupling coefficient (where i ≠ j); accepting at least first and second signals from the at least first and second devices under test (DUT) indicating the at least first and second devices under test (DUT) Corresponding at least first and second power levels of the at least first and second controlled radio frequency (RF) signals received and associated with the plurality of wireless communication channel coefficients; and repeating the at least first and The control of the phase of the two wired radio frequency (RF) test signals until the direct-coupling coefficients are higher than the cross-coupling coefficients by a minimum amount. The method of claim 5, wherein: the at least first and second wired radio frequency (RF) test signals further have corresponding at least first and second wired radio frequency (RF) test signal sizes; and the method further comprises Controlling at least the first and second wired radio frequency (RF) test signal sizes to provide the corresponding at least first and second controlled radio frequency (RF) signals, and repeating the at least first and second wired radio frequencies (RF) The control of the signal size is controlled until the direct-coupling coefficients are approximately equal.