Array antenna active standing wave test calibration system and method

Abstract

The application belongs to the technical field of array antenna measurement, and discloses an array antenna active standing wave test calibration system and method, which comprises a plurality of vector network analyzers, a calibration module and a computer terminal, the plurality of vector network analyzers are divided into two groups and are respectively used as independent excitation sources and receivers. In the application, a plurality of multi-port vector network analyzers are used as coherent excitation sources, the plurality of vector network analyzers are connected with the calibration module, the calibration module is adjusted to obtain a plurality of coherent excitation signals, and the vector network analyzer is used to directly test the standing wave parameters of each antenna unit of the array. The automatic test shortens the time of array antenna active standing wave test, greatly improves the test efficiency, and has good scalability based on a standard instrument scheme.

Description

Technical Field

[0001] This application relates to the field of array antenna measurement technology, and more specifically, to an active standing wave test and calibration system and method for array antennas. Background Technology

[0002] Array antennas are widely used in radar, detection, and communication systems due to their high gain and flexible beamforming. In evaluating the performance of array antennas, the standing wave ratio (VSWR) is a crucial indicator. VSWR reflects the impedance matching degree between the radiating elements and transmission lines. As the phased array antenna beam scans, the phase relationships between the elements and each other change due to the mutual coupling between them. This causes variations in the S-parameters of the elements at different scanning angles, typically manifesting as a deterioration in active VSWR performance.

[0003] In antenna array testing and verification, when different array amplitude and phase excitations achieve different array beam directions, the actual standing wave (SWR) level of individual array elements deteriorates sharply, potentially causing the TR module to self-oscillate or even burn out due to severe load impedance mismatch. Previous testing equipment either tested the passive SWR of a single array element while other antenna elements were connected to a load, or calculated the active SWR using theoretical formulas after testing the passive SWR and the antenna array's total S-parameters. Conventional SWR measurement methods only measure the performance of isolated antenna elements when fed. However, considering the mutual coupling effect between elements, the SWR of the entire array when fed differs from that of isolated elements. Therefore, measuring isolated elements cannot accurately assess the performance of the entire array.

[0004] In addition, in the field of array antenna testing, some organizations have proposed using a single RF source and a two-port vector network analyzer configuration, along with customized beam control modules, coupling network modules, and switching network modules, to construct a multi-channel coherent excitation and measurement system. In such systems, non-standard customized modules account for a large proportion. On the one hand, non-standard customized modules have poor stability and cannot be measured and calibrated by third parties. On the other hand, customized modules are expensive, have poor scalability, and are difficult to upgrade and modify later, often resulting in wasted resources and hindering asset preservation. Summary of the Invention

[0005] Testing the standing wave (VSWR) of array antennas is a massive undertaking. Previous methods differ significantly from the actual active VSWR under amplitude and phase excitation conditions of the antenna array. Traditional active VSWR testing systems for array antennas involve numerous non-standard, customized modules, resulting in high system costs, inability to be calibrated by third-party metrology institutions, poor scalability, and potential resource waste. Improving the efficiency and reducing the cost of active VSWR testing for array antennas has become a pressing issue for the industry. To address these problems, this application provides an active VSWR testing and calibration system and method for array antennas.

[0006] The active standing wave test and calibration system and method for array antennas provided in this application adopts the following technical solution:

[0007] An active standing wave test and calibration system for an array antenna includes several vector network analyzers, a calibration module, and a computer terminal. The vector network analyzers are divided into two groups, which serve as independent excitation sources and receivers, respectively.

[0008] The computer terminal is connected to the control ports of the vector network analyzer and the calibration module via an Ethernet switch.

[0009] The output port of the multiport vector network analyzer, which serves as the excitation source, is connected to the input port of the calibration module;

[0010] Ports 1 and 2 of the vector network analyzer, which acts as a receiver, are connected to the front and rear ports of the calibration module, respectively, and ports 3 and 4 are connected to the Ref1 and Ref2 ports of the calibration module, respectively.

[0011] The output port of the calibration module is connected to the test port of the array antenna.

[0012] Furthermore, the calibration module includes an RF switch matrix unit, a coupler unit, and a phased synchronization unit.

[0013] Furthermore, the coherent synchronization unit includes several reference source modules, which are used to sequentially complete the coherent synchronization and phase control of multiple vector network analyzers.

[0014] Furthermore, a power divider is also provided between the vector network analyzer, which serves as the excitation source, and the calibration module to measure the amplitude and phase differences between the vector network analyzers and between the different channels of the calibration module.

[0015] Furthermore, it also includes an electronic calibration device and a power meter. The power meter is connected to the USB interface of the vector network analyzer, which serves as the excitation source. The electronic calibration device is connected to the calibration module via an RF cable and is also connected to the USB interface of the vector network analyzer. It is used to perform source output power, receiver power, and receiver linearity calibration operations.

[0016] A method for testing and calibrating active standing wave ratios of an array antenna, the method comprising the following steps:

[0017] S1. Perform full two-port calibration on ports 1 and 2 of the first set of vector network analyzers, which serve as the excitation source.

[0018] S2. Connect the output ports of the first group of vector network analyzers 1 to n to the source port of the calibration module respectively;

[0019] S3. Set the start and end frequencies and the number of measurement points for the standing wave test;

[0020] S4. Measure the amplitude and phase differences between corresponding ports of each vector network analyzer and between each channel of the calibration module to perform inherent error calibration of the calibration module.

[0021] S5. Calibrate the source output power, receiver power, and receiver linearity, and complete the calibration operation of each channel of the calibration module in sequence.

[0022] S6. Perform standing wave testing via computer terminal, control the internal switching channel path of the calibration module, and measure the ratio between the forward and backward channels in sequence to obtain the standing wave measurement results of each channel.

[0023] Furthermore, the inherent error calibration of the calibration module in S4 includes the following steps:

[0024] S401. Use electronic calibration kits to calibrate the S-parameters of ports 1 and 2 of the second group of vector network analyzers;

[0025] S402. Connect a power divider to port 1 of the first group of vector network analyzers 1, connect output 1 of the power divider to source 1 port of the calibration module, connect calibration modules Ref1 and Ref2 to ports 3 and 4 of the second group of vector network analyzers respectively, and connect measurement channels 1 and 5 of the calibration modules to ports 1 and 2 of the second group of vector network analyzers respectively.

[0026] S403. Connect the output 2 of the power divider to the source 5 port of the calibration module, and measure the amplitude difference and phase difference of Ref1 and Ref2 of the first group of vector network analyzers 1 and 2, respectively, as well as the amplitude difference and phase difference of the calibration module measuring channels 1 and 5.

[0027] S404. Connect the output 2 of the power divider to the source 9 port of the calibration module, and measure the amplitude difference and phase difference of Ref1 and Ref2 of the first group of vector network analyzers 1 and 2, and measure the amplitude difference and phase difference of measurement channels 1 and 9 of the calibration module.

[0028] Furthermore, the calibration of the source output power, receiver power, and receiver linearity in S5 includes the following steps:

[0029] S501. Connect the output ports 1 to 4 of the calibration module to the second set of vector network analyzers through electronic calibration components, and calibrate each port in turn.

[0030] S502. Connect the electronic calibration kit and USB power meter to the first group of vector network analyzers 1, and calibrate the S-parameters and power of its ports 1 to 4;

[0031] S503. Connect the output ports 4n+1 to 4n+4 (n≥1) of the calibration module to the second set of vector network analyzers in sequence through electronic calibration components, and calibrate each port in sequence.

[0032] S504. Connect the electronic calibration kit and USB power meter to the first group of vector network analyzers n+1, and calibrate the S-parameters and power of ports 1 to 4.

[0033] Furthermore, the standing wave testing method in S6 includes the following steps:

[0034] S601. Connect the calibration module to the antenna array under test;

[0035] S602. Based on the phase difference between the second group of vector network analyzers Ref1 and Ref2, adjust the calibration module configuration and set the phase value between the first group of vector network analyzers.

[0036] S603. Use the second set of vector network analyzers to collect forward and backward test results, adjust the internal channel switching of the calibration module in sequence, and record the relevant test results;

[0037] S604. Switch the frequency point and repeat S602 to S603 to obtain the active standing wave test results at different frequencies.

[0038] In summary, this application includes at least one of the following beneficial technical effects:

[0039] (1) This application uses multiple multi-port vector network analyzers as coherent excitation sources, connects multiple vector network analyzers to a calibration module, and obtains multiple coherent excitation signals by adjusting the calibration module. The standing wave parameters of each antenna element of the array are directly tested using the vector network analyzer. Automatic testing shortens the testing time of active standing wave of the array antenna and greatly improves the testing efficiency.

[0040] (2) This application proposes a method for coherent synchronization between multiple vector network analyzers. The coherent output excitation sources in the array antenna test system are all composed of independent excitation sources inside the vector network analyzer. Standardized instruments and equipment are used to ensure the system index parameters. At the same time, it provides the possibility for third-party measurement. The system has good scalability and effectively reduces the test cost and subsequent maintenance cost. Attached Figure Description

[0041] Figure 1 This is a connection diagram of the test calibration system of this application;

[0042] Figure 2 This is a flowchart illustrating the testing and calibration method of this application;

[0043] Figure 3 This is a schematic diagram of the calibration process for the inherent error of the calibration module in S4 of this application;

[0044] Figure 4 This is a schematic diagram of the process for calibrating the source output power, receiver power, and receiver linearity in S5 of this application;

[0045] Figure 5 This is a flowchart illustrating the standing wave testing method in S6 of this application. Detailed Implementation

[0046] The technical solutions in the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application.

[0047] In the description of this application, it should be noted that the terms "upper," "lower," "inner," "outer," "top / bottom," etc., indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0048] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installed," "equipped with," "sleeved / connected," "connected," etc., should be interpreted broadly. For example, "connection" can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium; it can be a connection within two components. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0049] Example 1:

[0050] The following is in conjunction with the appendix Figure 1-5 This application will be described in further detail.

[0051] This application discloses an active standing wave (VSWR) test and calibration system for an array antenna, comprising several vector network analyzers, a calibration module, and a computer terminal. The vector network analyzers are divided into two groups. The first group of vector network analyzers is used as an independent excitation source and consists of n 4-port vector network analyzers. Common vector network analyzers have 2 / 4 independent signal sources, and for the same vector network analyzer, the internal signal sources are required to have coherent output characteristics. The second group of vector network analyzers consists of one 4-port vector network analyzer and is used as four independent receivers.

[0052] The computer terminal is connected to the control ports of the vector network analyzer and the calibration module via an Ethernet switch;

[0053] The output port of the first set of multi-port vector network analyzers, which serves as the excitation source, is connected to the input of the calibration module;

[0054] Ports 1 and 2 of the second set of vector network analyzers, which serve as receivers, are connected to the front and rear ports of the calibration module, respectively, and ports 3 and 4 are connected to the Ref1 and Ref2 ports of the calibration module, respectively.

[0055] The calibration module output port is connected to the test port of the array antenna.

[0056] Furthermore, the calibration module includes an RF switch matrix unit, a coupler unit, and a phased synchronization unit.

[0057] Furthermore, the coherent synchronization unit includes several reference source modules, which are used to sequentially complete the coherent synchronization and phase control of multiple vector network analyzers.

[0058] Furthermore, a power divider is installed between the vector network analyzer, which serves as the excitation source, and the calibration module to measure the amplitude and phase differences between the vector network analyzers and between the different channels of the calibration module.

[0059] Furthermore, it also includes an electronic calibration device and a power meter. The power meter is connected to the USB interface of the vector network analyzer, which serves as the excitation source. The electronic calibration device is connected to the calibration module via an RF cable and to the USB interface of the vector network analyzer, and is used to perform source output power, receiver power, and receiver linearity calibration operations.

[0060] The implementation principle of the active standing wave (VSWR) test and calibration system and method for array antennas in this application embodiment is as follows: Through user-defined port configuration of the vector network analyzer, the second group of vector network analyzer receivers b1 is defined as receiver a of logic port 1, and the second group of vector network analyzer receivers b2 is defined as receiver b of logic port 1. This facilitates operation. The measurement results of the vector network analyzer user interface S11 are used as the antenna test results. The VSWR test can be completed by setting the trace through the vector network analyzer. By switching the internal RF switch of the calibration module, the VSWR of each antenna in the array can be measured sequentially. By adjusting the output phase of the reference source module inside the calibration module, the coherent synchronization and phase control of multiple vector network analyzers can be completed sequentially. The directional coupler unit inside the calibration module completes the measurement functions of the excitation signal and reflection signal at the measurement port.

[0061] This embodiment also discloses a method for testing and calibrating active standing waves of an array antenna, including the following steps:

[0062] S1. Perform full two-port calibration on ports 1 and 2 of the first set of vector network analyzers, which serve as the excitation source.

[0063] S2. Connect the output ports of the first group of vector network analyzers 1 to n to the source ports of the calibration module respectively. The corresponding relationship is that vector network analyzer 1 is connected to source ports 1 to 4, vector network analyzer 2 is connected to source ports 5 to 8, and so on. Vector network analyzer n is connected to source ports 4n-3 to 4n.

[0064] S3. Set the start and end frequencies, number of measurement points, etc. for the standing wave test in the control software;

[0065] S4. Measure the amplitude and phase differences between corresponding ports of each vector network analyzer and between each channel of the calibration module to perform inherent error calibration of the calibration module.

[0066] S5. Calibrate the source output power, receiver power, and receiver linearity, and complete the calibration operation of each channel of the calibration module in sequence.

[0067] S6. Perform standing wave testing via computer terminal, control the internal switching channel path of the calibration module, and measure the ratio between the forward and backward channels in sequence to obtain the standing wave measurement results of each channel.

[0068] Furthermore, the inherent error calibration of the calibration module in S4 includes the following steps:

[0069] S401. Connect two test cables to ports 1 and 2 of the second group of vector network analyzers. Connect the USB of the electronic calibration kit to the USB interface of the second group of vector network analyzers. Select the full dual-port calibration function of the vector network analyzer to calibrate the S-parameters of ports 1 and 2. It should be noted that the output ports of the first group of vector network analyzers 1 to n are connected to the source ports of the calibration module respectively. The corresponding relationship is that vector network analyzer 1 is connected to source ports 1 to 4, vector network analyzer 2 is connected to source ports 5 to 8, and so on. Vector network analyzer n is connected to source ports 4n-3 to 4n.

[0070] S402. Connect a power divider to port 1 of the first group of vector network analyzers 1, connect output 1 of the power divider to source 1 port of the calibration module, connect calibration modules Ref1 and Ref2 to ports 3 and 4 of the second group of vector network analyzers respectively, and connect measurement channels 1 and 5 of the calibration modules to ports 1 and 2 of the second group of vector network analyzers respectively.

[0071] S403. Connect the output 2 of the power divider to the source 5 port of the calibration module, and measure the amplitude difference and phase difference of Ref1 and Ref2 of the first group of vector network analyzers 1 and 2, respectively, as well as the amplitude difference and phase difference of the calibration module measuring channels 1 and 5.

[0072] S404. Connect the output 2 of the power divider to the source 9 port of the calibration module, and measure the amplitude difference and phase difference of Ref1 and Ref2 of the first group of vector network analyzers 1 and 2, and measure the amplitude difference and phase difference of measurement channels 1 and 9 of the calibration module.

[0073] Furthermore, the calibration of source output power, receiver power, and receiver linearity in S5 includes the following steps:

[0074] S501. Connect the output ports 1-4 of the calibration module to the electronic calibration component via RF cables. Connect the electronic calibration component to the USB interface of the second group of vector network analyzers and perform single-port calibration at channels 1 / 2 / 3 / 4 respectively. Connect the electronic calibration component to the USB port of the first group of vector network analyzers 1 and perform full four-port S-parameter calibration. Connect the power meter to the USB port of the first group of vector network analyzers 1 and perform source output power, receiver power, and receiver linearity calibration operations respectively.

[0075] S502. Connect the calibration module channels 5 / 6 / 7 / 8 to the electronic calibration component via RF cables. Connect the electronic calibration component to the USB interface of the second vector network analyzer and perform single-port calibration at channels 5 / 6 / 7 / 8 respectively. Connect the electronic calibration component to the USB interface of the first vector network analyzer 2 and perform full four-port S-parameter calibration. Connect the power meter to the USB interface of the first vector network analyzer 2 and perform source output power, receiver power, and receiver linearity calibration operations respectively. Complete the calibration operations for the other channels of the calibration module in sequence.

[0076] S503. Connect the output ports 4n+1 to 4n+4 (n≥1) of the calibration module to the second set of vector network analyzers in sequence through electronic calibration components, and calibrate each port in sequence.

[0077] S504. Connect the electronic calibration kit and USB power meter to the first group of vector network analyzers n+1, and calibrate the S-parameters and power of ports 1 to 4.

[0078] Furthermore, the standing wave testing method in S6 includes the following steps:

[0079] S601. Connect the calibration module to the antenna array under test;

[0080] S602. Based on the phase difference between the second group of vector network analyzers Ref1 and Ref2, adjust the calibration module configuration and set the phase value between the first group of vector network analyzers.

[0081] S603. Use the second set of vector network analyzers to collect forward and backward test results, adjust the internal channel switching of the calibration module in sequence, and record the relevant test results;

[0082] S604. Switch the frequency point and repeat S602 to S603 to obtain the active standing wave test results at different frequencies.

[0083] It should be noted that when clicking on the standing wave test in the control software, the system will automatically set the output frequency of the first / second group of vector network analyzers and set the first / second group of vector network analyzers to work in CW mode. The first group of vector network analyzers uses manual trigger mode. Based on the phase difference between Ref1 and Ref2 of the second group of vector network analyzers, the phase difference between channels 1 and 5 of the first group of vector network analyzers is adjusted. The channel switching path inside the calibration module is adjusted, and the phase difference between Ref1 and Ref2 is repeatedly measured. The phase difference between channels 1 and n of the first group of vector network analyzers is adjusted sequentially until the first group of vector network analyzers reaches a coherent state. The channel switching path inside the calibration module is controlled to measure the ratio between the forward and backward channels sequentially, thereby obtaining the standing wave measurement results of each channel.

[0084] The above are all preferred embodiments of this application, and are not intended to limit the scope of protection of this application. Therefore, all equivalent changes made in accordance with the structure, shape and principle of this application should be covered within the scope of protection of this application.

Claims

1. An active standing wave (VSWR) test and calibration system for an array antenna, characterized in that: It includes several vector network analyzers, a calibration module and a computer terminal. The vector network analyzers are divided into two groups, which serve as independent excitation sources and receivers, respectively. The computer terminal is connected to the control ports of the vector network analyzer and the calibration module via an Ethernet switch. The output port of the multi-port vector network analyzer, which serves as the excitation source, is connected to the input port of the calibration module; Ports 1 and 2 of the vector network analyzer, which acts as a receiver, are connected to the front and rear ports of the calibration module, respectively, and ports 3 and 4 are connected to the Ref1 and Ref2 ports of the calibration module, respectively. The output port of the calibration module is connected to the test port of the array antenna.

2. The active standing wave test and calibration system for an array antenna according to claim 1, characterized in that: The calibration module includes an RF switch matrix unit, a coupler unit, and a phased synchronization unit.

3. The active standing wave test and calibration system for array antennas according to claim 2, characterized in that: The coherent synchronization unit includes several reference source modules, which are used to sequentially complete the coherent synchronization and phase control of multiple vector network analyzers.

4. The active standing wave test and calibration system for array antennas according to claim 1, characterized in that: A power divider is also provided between the vector network analyzer, which serves as the excitation source, and the calibration module, for measuring the amplitude and phase differences between the vector network analyzers and between the different channels of the calibration module.

5. The active standing wave test and calibration system for an array antenna according to claim 1, characterized in that: It also includes an electronic calibration device and a power meter. The power meter is connected to the USB interface of the vector network analyzer, which serves as the excitation source. The electronic calibration device is connected to the calibration module via an RF cable and is also connected to the USB interface of the vector network analyzer. It is used to perform source output power, receiver power, and receiver linearity calibration operations.

6. A method for testing and calibrating active standing wave ratios of an array antenna, characterized in that: The method includes the following steps: S1. Perform full two-port calibration on ports 1 and 2 of the first set of vector network analyzers, which serve as the excitation source. S2. Connect the output ports of the first group of vector network analyzers 1 to n to the source port of the calibration module respectively; S3. Set the start and end frequencies and the number of measurement points for the standing wave test; S4. Measure the amplitude and phase differences between corresponding ports of each vector network analyzer and between each channel of the calibration module to perform inherent error calibration of the calibration module; S5. Calibrate the source output power, receiver power, and receiver linearity, and complete the calibration operation of each channel of the calibration module in sequence. S6. Perform standing wave testing via computer terminal, control the internal switching channel path of the calibration module, and measure the ratio between the forward and backward channels in sequence to obtain the standing wave measurement results of each channel.

7. The active standing wave test and calibration method for an array antenna according to claim 6, characterized in that: The inherent error calibration of the calibration module in step S4 includes the following steps: S401. Use electronic calibration kits to calibrate the S-parameters of ports 1 and 2 of the second group of vector network analyzers; S402. Connect a power divider to port 1 of the first group of vector network analyzers 1, connect output 1 of the power divider to source 1 port of the calibration module, connect calibration modules Ref1 and Ref2 to ports 3 and 4 of the second group of vector network analyzers respectively, and connect measurement channels 1 and 5 of the calibration modules to ports 1 and 2 of the second group of vector network analyzers respectively. S403. Connect the output 2 of the power divider to the source 5 port of the calibration module, and measure the amplitude difference and phase difference of Ref1 and Ref2 of the first group of vector network analyzers 1 and 2, respectively, as well as the amplitude difference and phase difference of the calibration module measuring channels 1 and 5. S404. Connect the output 2 of the power divider to the source 9 port of the calibration module, and measure the amplitude difference and phase difference of Ref1 and Ref2 of the first group of vector network analyzers 1 and 2, and measure the amplitude difference and phase difference of measurement channels 1 and 9 of the calibration module.

8. The active standing wave test and calibration method for an array antenna according to claim 6, characterized in that: The calibration of source output power, receiver power, and receiver linearity in S5 includes the following steps: S501. Connect the output ports 1 to 4 of the calibration module to the second set of vector network analyzers through electronic calibration components, and calibrate each port in turn. S502. Connect the electronic calibration kit and USB power meter to the first group of vector network analyzers 1, and calibrate the S-parameters and power of its ports 1 to 4; S503. Connect the output ports 4n+1 to 4n+4 (n≥1) of the calibration module to the second set of vector network analyzers in sequence through electronic calibration components, and calibrate each port in sequence. S504. Connect the electronic calibration kit and USB power meter to the first group of vector network analyzers n+1, and calibrate the S-parameters and power of ports 1 to 4.

9. The active standing wave test and calibration method for an array antenna according to claim 6, characterized in that: The standing wave testing method in S6 includes the following steps: S601. Connect the calibration module to the antenna array under test; S602. Based on the phase difference between the second group of vector network analyzers Ref1 and Ref2, adjust the calibration module configuration and set the phase value between the first group of vector network analyzers. S603. Use the second set of vector network analyzers to collect forward and backward test results, adjust the internal channel switching of the calibration module in sequence, and record the relevant test results; S604. Switch the frequency point and repeat S602 to S603 to obtain the active standing wave test results at different frequencies.

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