CN115542268A - Large-aperture phased array antenna block testing method and system - Google Patents

Abstract

The invention provides a large-diameter phased array antenna block test method and test system. This method divides the original large-scale antenna into several sub-arrays, completes the test of the sub-array antenna in the dark room each time, and finally performs scientific and effective numerical synthesis calculation on the data of the block test, and can complete the radiation pattern of the entire large-aperture antenna Synthesis. This method solves the contradiction between the limited space of the darkroom and the large-aperture requirements of the antenna to be tested, and greatly improves the efficiency and accuracy of large-scale antenna array testing.

Description

A large-aperture phased array antenna block test method and test system

technical field

The invention belongs to the technical field of antenna testing, and in particular relates to a large-diameter phased array antenna block testing method and testing system.

Background technique

In recent years, spaceborne radar systems based on satellite platforms are developing rapidly. With the characteristics of high mobility, wide coverage and all-weather work of satellite platforms, satellite radars are widely used in global surveying and mapping, space communications, satellite-ground interconnection and other fields. As the core component of the radar system, the phased array antenna is mainly used to convert radio frequency signals into electromagnetic waves to radiate into space and receive electromagnetic waves from space. With the continuous upgrading of system application requirements, the aperture of phased array antennas continues to increase, and the complexity of the system continues to increase. In addition to putting forward higher requirements for system design, the difficulty of testing antennas has also greatly increased. Due to the high requirements on the cleanliness, temperature and humidity of the space environment, the spaceborne phased array antenna cannot complete the pattern test outdoors, but can only be carried out in a microwave anechoic chamber with aerospace test conditions. With the lowering of the application frequency band of spaceborne radar and the increase of the antenna aperture, the demand for the darkroom space of the pattern test is increasing. At present, the effective test aperture of the domestic aerospace microwave anechoic chamber is far from meeting the test requirements of large phased array antenna pattern. It is not a good solution to expand the darkroom according to the antenna caliber, the cost is huge, and the test stability cannot be guaranteed. Therefore, the research and development of large-scale phased array antenna block testing system is imminent.

Contents of the invention

The invention breaks through the limitation of the antenna caliber by the existing near-field measurement method, and proposes a block testing method for the large-diameter antenna. This method divides the original large-scale antenna into several sub-arrays, completes the test of the sub-array-level antenna in the dark room each time, and finally performs scientific and effective numerical synthesis calculation on the data of the block test, and can complete the radiation direction of the entire large-aperture antenna. Composition of graphs. This method solves the contradiction between the limited space of the darkroom and the large-aperture requirements of the antenna to be tested, and greatly improves the efficiency and accuracy of large-scale antenna array testing.

The invention provides a large-diameter phased array antenna block test method and a test system, which are used to solve the problem that the darkroom test space cannot meet the test requirements of large-scale antennas.

The invention provides a large-diameter phased array antenna block test method, the method steps are as follows:

Step 1. According to the effective test range of the microwave anechoic chamber, the large-aperture phased array antenna is divided into several sub-arrays suitable for the size of the anechoic chamber. The number of sub-arrays is set to n, and the number of antenna sub-arrays is i, i=1, 2, ..., n, each test a sub-array;

Step 2. Place the antenna sub-array i to be tested in the microwave anechoic chamber and complete the position calibration

Place the subarray i to be tested in the microwave anechoic chamber, i=1, 2,...,n, calibrate the relative position between the subarray to be tested and the test probe through the antenna installation and positioning system, so that the plane of the subarray is parallel to the test plane of the probe And the flatness of the antenna sub-array meets certain requirements; record the relative positional relationship between the starting position of the probe test and the sub-array to be tested, and ensure that the phase center of each sub-array test is constant;

Step 3. Complete the antenna subarray i test system configuration in the microwave anechoic chamber

Set antenna test parameters through terminal display and control system and test servo system, including: test probe scanning range, scanning step, scanning rate; RF detection system operating frequency, sampling rate, test wave position, antenna receiving/transmitting state selection, etc.

Step 4. Run the test system to complete the acquisition of near-field plane amplitude and phase data of the subarray to be tested

This step can be completed through the cooperation of the test servo system and the radio frequency detection system. The test servo system controls the test probe to move to the designated position, and the radio frequency detection system samples the radio frequency signal at the designated position, obtains the electric field amplitude and phase information of the corresponding position, and stores the information in the terminal display and control system;

Step 5. Calculate the far-field pattern f _i of the antenna subarray

According to the near-field amplitude and phase data, adopt the near-far field transformation method to calculate the far-field pattern f _i of the sub-array, i=1, 2, ..., n;

Step 6. Repeat test steps 2 to 6 to complete the acquisition of near-field amplitude and phase data and calculation of far-field pattern for all subarrays;

Step 7. Carry out vector synthesis of the far-field pattern _fi of each sub-array according to the relative positional relationship of the sub-arrays, and calculate the far-field pattern of the whole array;

This step regards the far-field pattern fi of each _subarray as the unit pattern. According to the arrangement and division of sub-arrays, the phase center of each sub-array can be corrected by referring to the following formula, and finally the far-field radiation pattern F of all sub-arrays is synthesized by far-field vector to obtain the final far-field radiation pattern F.

In the formula: F is the final pattern of the large aperture phased array antenna;

f _i is the far field pattern of each sub-array, i=1, 2,..., n;

k is the wave number, k=2π/λ, and λ is the wavelength;

u=sin(θ)cos(φ);

v=sin(θ)sin(φ);

x _i , y _i are the relative positions of the ith sub-array in the large aperture phased array antenna.

The invention provides a large-diameter phased array antenna block test system, including: a terminal display and control system, a test servo system, a radio frequency detection system, and an antenna installation and positioning system.

The terminal display and control system is used to coordinate and complete the state configuration and collaborative work among the antenna under test, test servo system, and radio frequency detection system, including: state configuration of the antenna under test, servo control, radio frequency system state configuration, test data collection, test Functions such as data storage, test process display and test result processing.

The test servo system is used to complete the mechanical movement of the test equipment during the antenna test process. The test servo system includes a planar near-field scanning frame and a control terminal. The terminal display and control system can send the test status control command to the test servo system, and the test servo system can control the operating status of the plane near-field scanning frame to complete the antenna test according to the command.

The radio frequency detection system is used to complete the collection of test antenna data. The radio frequency detection system includes: vector network analyzer, test probe, test interconnection cable, etc. The vector network analyzer is interconnected with the test probes and the antenna under test through the test interconnection cable. The relevant test status of the vector network analyzer can be configured through the terminal display and control system.

The antenna installation and positioning system is used to complete the installation, fixing and position calibration of the antenna to be tested. The antenna installation and positioning system includes the antenna installation equipment to be tested and the optical positioning equipment. Before each antenna sub-array test, it needs to be installed in the same position, and the relative positional relationship between the test probe and the antenna under test should be calibrated by optical positioning equipment.

The beneficial effects of the present invention are:

The test method and test system provided by the invention can split a large antenna into several sub-arrays, and complete the antenna pattern test in blocks. Compared with the traditional test method, this method can reduce the space requirements of the test site for large-aperture antenna testing, and at the same time improve the efficiency of antenna test troubleshooting. The test process is flexible and the test efficiency is high. the contradiction between.

Description of drawings

Fig. 1 is the block test method flow chart of large aperture phased array antenna;

Figure 2 is a schematic diagram of the large-aperture phased array antenna block test system;

Fig. 3 is a schematic diagram of the sub-array division of the large-aperture phased array antenna.

detailed description

The technical solutions provided by the present invention will be described in detail below in conjunction with specific examples. It should be understood that the following specific embodiments are only used to illustrate the present invention and are not intended to limit the scope of the present invention.

The present invention solves the problem of large-diameter phased array antenna testing. The general idea is as follows: by dividing the original large-scale antenna into blocks, the test of some antennas is completed in the dark room each time, and finally the data of the block test is scientifically and effectively synthesized. The calculation can complete the synthesis of the radiation pattern of the entire large-aperture antenna.

Embodiment one:

Please refer to Fig. 1 and Fig. 2, the present invention provides a large aperture phased array antenna block test method, which is applied to the phased array antenna block test system, including:

Step 1. According to the effective test range of the microwave anechoic chamber, the large-aperture phased array antenna is divided into several sub-arrays suitable for the size of the anechoic chamber. The number of sub-arrays is set to n, and the number of antenna sub-arrays is i, i=1, 2, ..., n, each test a sub-array;

The sub-array is divided based on the two-dimensional effective scanning capability of the microwave anechoic chamber, and the size of the sub-array must be smaller than or equal to the effective scanning range of the microwave anechoic chamber. In the case of meeting the conditions of the microwave anechoic chamber, the number of sub-arrays is not limited;

Since the microwave anechoic chambers vary in size, the effective test range of the microwave anechoic chamber can be determined according to the actual situation. For example, the effective test range of a microwave anechoic chamber is 25 meters in azimuth and 20 meters in distance. The aperture of the phased array antenna is 50 meters in azimuth and 40 meters in distance. Then the phased array antenna can be divided into 4 sub-arrays arranged as 2╳2. The size of each sub-array is 25 meters in azimuth and 20 meters in distance. Each sub-array can be adapted to the effective test range of the microwave anechoic chamber. In special cases, the size of the sub-array can be divided into smaller ones according to the structural composition of the phased array antenna. In short, the subarray division principle is that the size of the subarray adapts to the effective measurement range of the microwave anechoic chamber.

Step 2. Place the antenna sub-array i to be tested in the microwave anechoic chamber and complete the position calibration

Place the subarray i to be tested in the microwave anechoic chamber, i=1, 2,...,n, calibrate the relative position between the subarray to be tested and the test probe through the antenna installation and positioning system, so that the plane of the subarray is parallel to the test plane of the probe And the flatness of the antenna sub-array meets certain requirements; record the relative positional relationship between the starting position of the probe test and the sub-array to be tested, and ensure that the phase center of each sub-array test is constant;

The antenna installation and positioning system uses optical positioning equipment and a test servo system to work together. The optical positioning equipment moves through the test servo system to sample several points on the surface of the phased array antenna and record the three coordinates of each sampling point. The flatness data of the phased array antenna is fitted by the coordinate data of the sampling points. The flatness index can be adapted according to the specific requirements of each phased array antenna. If the current state does not meet the requirements, it can be corrected by adjusting the angle of the phased array antenna. During each sub-array test, the relative positional relationship between the probe test starting position and the sub-array to be tested must be consistent. This is to ensure that the phase center of each sub-array test is constant, and to avoid phase center errors during pattern synthesis later.

Step 3. Complete the antenna subarray i test system configuration in the microwave anechoic chamber

Set antenna test parameters through terminal display and control system and test servo system, including: test probe scanning range, scanning step, scanning rate, RF detection system operating frequency, sampling rate, test wave position, antenna receiving/transmitting state selection, etc.

The antenna test parameters can be set according to the test requirements of different antennas. Testers can set parameters such as the scanning range, scanning step, and scanning rate of the test probe through the terminal display and control system software according to the basic requirements of antenna near-field measurement.

Step 4. Run the test system to complete the acquisition of near-field plane amplitude and phase data of the subarray i to be tested;

Step 5. Calculate the far-field pattern f _i of the antenna subarray

According to the near-field plane amplitude and phase data, the near-far field transformation method is used to calculate the far-field pattern f _i of the sub-array, i=1, 2, ..., n;

In this step, the obtained near-field information is converted into a far-field pattern through a near-far field transformation program according to the equivalent principle.

Step 6. Repeat test steps 2 to 6 to complete the acquisition of near-field amplitude and phase data and calculation of far-field pattern for all subarrays;

Step 7: Carry out vector synthesis of the far-field pattern _fi of each sub-array according to the relative positional relationship of the sub-arrays, and calculate the far-field pattern of the whole array.

This step regards the far-field pattern fi of each _subarray as the unit pattern. According to the arrangement and division of sub-arrays, the phase center of each sub-array can be corrected by referring to the following formula, and finally the far-field radiation pattern F of all sub-arrays is synthesized by far-field vector to obtain the final far-field radiation pattern F.

In the formula: F is the final pattern of the large aperture phased array antenna;

f _i is the far field pattern of each sub-array, i=1, 2,..., n;

k is the wave number, k=2π/λ, and λ is the wavelength;

u=sin(θ)cos(φ);

v=sin(θ)sin(φ);

x _i , y _i are the relative positions of the ith sub-array in the large aperture phased array antenna.

For example: the caliber of the phased array antenna is 50 meters in the azimuth direction and 40 meters in the distance direction. If the phased array antenna can be divided into 4 sub-arrays, the size of each sub-array is 25 meters in the azimuth direction and 20 meters in the distance direction. Then x ₁ =-25 meters, y ₁ =20 meters. A specific example is shown in Figure 3.

Embodiment two:

The present invention provides a large-diameter phased array antenna block test system, which can be applied to the block test method, please refer to Figure 2, the system includes: terminal display and control system, test servo system, radio frequency detection system, antenna installation and positioning system .

The terminal display and control system software is built using the Qt development environment, and is responsible for coordinating and completing the state configuration and collaborative work among the antenna to be tested, the test servo system, and the radio frequency detection system, including: state configuration of the antenna to be tested, servo control, state configuration of the radio frequency system, Functions such as test data collection, test data storage, test process display and test result processing. Antenna status configuration includes antenna operating frequency, transceiver operating status selection, and test wave position; servo control includes test probe scanning range, scanning step, and scanning rate; RF system status configuration includes RF system operating frequency and sampling rate. The terminal display and control system is interconnected with the test servo system and radio frequency detection system through COM, LAN, GPIB and other standard communication interfaces to realize clock synchronization, data transmission, data storage and other functions.

The test servo system is responsible for completing the mechanical movement of the test equipment during the antenna test process, including the planar near-field scanning frame and the control terminal. The planar near-field scanning frame includes an antenna installation platform to be tested, a test probe installation bracket, and a probe movement guide rail. The installation platform of the antenna to be tested and the installation bracket of the test probe are reserved for the installation of different types of antennas and probes to be tested. The probe motion guide rail has horizontal and vertical two-dimensional motion capabilities, and can choose continuous motion mode or step stop mode according to user needs. Probe movement accuracy can be achieved 0.01mm. The control terminal software is written in VC++. The trajectory of the probe can be set through the software interface, including the probe moving path, moving speed, moving mode, etc.

The radio frequency detection system is responsible for completing the data collection of the test antenna, including: vector network analyzer, test probe, test interconnection cable, etc. The vector network analyzer and test interconnect cable interface is SMA. Port 1 of the vector network analyzer is connected to the test probe through a test interconnection cable, and port 2 is connected to the antenna under test through a test interconnection cable. In order to adapt to the interface of different types of antennas, the test interconnection cable can use a special adapter to transform the SMA connector. Through the terminal display and control system, the parameters of the vector network analyzer can be set, such as test frequency, test level, etc., and the radio frequency information collected by the vector network analyzer is transmitted to the terminal display and control system through the LAN interface for storage. The test probe is fixed on the scanning frame of the test servo system. With the movement of the scanning frame, the test probe can sample the space electric field at the specified position.

The antenna installation and positioning system is responsible for completing the installation, fixing and position calibration of the antenna under test, including the installation equipment of the antenna under test and the optical positioning equipment. First, install the antenna to be tested on the antenna installation device to be tested. The equipment is reserved with installation positioning holes, which can ensure the constant installation position of each sub-array. The optical positioning equipment is to ensure that the test phase center of each sub-array is constant. Before the sub-array pattern test, the optical positioning device can be installed on the scanning frame, and the laser spot can be irradiated on the antenna to be tested. Move the scanning frame until the laser beam is irradiated on the installation positioning hole of the antenna to be tested, then this position is the standard starting position of the test probe. Remove the optical positioning device and replace it with a test probe to start the test.

So far, the large-aperture phased array antenna block test method and test system of the present invention have been described in detail with reference to the accompanying drawings. Based on the above description, those skilled in the art should have a clear understanding of the present invention.

The above description is only the best specific implementation mode of the present invention, but the scope of protection of the present invention is not limited thereto. Any person skilled in the art can easily conceive of changes or modifications within the technical scope disclosed in the present invention. Replacement should be covered within the protection scope of the present invention.

The content that is not described in detail in the specification of the present invention belongs to the well-known technology of those skilled in the art.

Claims (10)

1. A large aperture phased array antenna block test system, comprising: the system comprises a terminal display control system, a test servo system, a radio frequency detection system and an antenna installation positioning system;

the terminal display control system is used for coordinating and completing state configuration and cooperative work among the antenna to be tested, the test servo system and the radio frequency detection system;

the test servo system is used for completing the mechanical motion of test equipment in the antenna test process and comprises a planar near-field scanning frame and a control terminal;

the radio frequency detection system is used for completing the acquisition of test antenna data, and comprises: a vector network analyzer, a test probe, and a test interconnection cable;

and the antenna mounting and positioning system is used for completing mounting and fixing and position calibration of the antenna to be detected and comprises antenna mounting equipment to be detected and optical positioning equipment.

2. The system of claim 1, wherein the terminal display control system performs state configuration of the antenna to be tested, servo control, state configuration of the radio frequency system, test data acquisition, test data storage, test process display, and test result processing.

3. The system of claim 1, wherein the terminal display control system sends the test state control command to the test servo system, and the test servo system controls the operation state of the planar near-field scanning frame according to the command to complete the antenna test.

4. The system of claim 1, wherein the vector network analyzer is interconnected with the test probe and the antenna under test via a test interconnection cable; and configuring the relevant test state of the vector network analyzer through the terminal display control system.

5. The system of claim 1, wherein the antenna array is mounted at the same position before each testing, and the relative position relationship between the test probe and the antenna to be tested is calibrated by the optical positioning device.

6. A large-aperture phased array antenna block testing method is characterized by comprising the following steps:

step 1, dividing a large-aperture phased array antenna into a plurality of subarrays which are adaptive to the size of a darkroom according to the effective test range of the darkroom, wherein the number of the subarrays is set to be n, the antenna subarrays are numbered to be i, i =1, 2, 8230, and n, and one subarray is tested each time;

step 2, placing the antenna subarray i to be tested in a microwave darkroom to finish position calibration

Step 3, completing the antenna subarray i test system configuration in the microwave darkroom

Step 4, operating the test system to complete the recording of the amplitude and phase data of the near-field plane of the subarray to be tested

Step 5, calculating a far field directional diagram f of the antenna subarray _i

Calculating a far-field directional diagram f of the subarray according to the near-field amplitude and phase data by adopting a near-far field transformation method _i ，i＝1、2、…、n；

Step 6, repeating the testing steps 2-6, and completing the recording of the near field amplitude phase data and the calculation of the far field directional diagram of all the sub-arrays;

step 7, the far field directional diagram f of each sub-array _i And carrying out vector synthesis according to the relative position relationship of the subarrays, and calculating to obtain a full-array-face far-field directional diagram.

7. The method as claimed in claim 6, wherein in step 2, the subarray i to be tested is placed in a microwave darkroom, i =1, 2, \8230, n, and the relative position between the subarray to be tested and the test probe is calibrated through an antenna installation positioning system, so that the subarray plane is parallel to the probe test plane and the antenna subarray flatness meets certain requirements; and recording the relative position relation between the test starting position of the probe and the subarray to be tested, and ensuring that the phase center of each subarray is constant.

8. The method of claim 6, wherein in step 3, the setting of the antenna test parameters by the terminal display control system and the test servo system comprises: testing the scanning range, scanning step and scanning speed of the probe; the radio frequency detection system has the working frequency, the sampling rate, the test wave position and the antenna receiving/transmitting state selection.

9. The method of claim 6, wherein in step 4, the step is performed by a test servo system and a radio frequency probe system; the test servo system controls the test probe to move to a specified position, the radio frequency detection system carries out radio frequency signal sampling at the specified position, electric field amplitude and phase information of the corresponding position are obtained, and the information is stored in the terminal display control system.

10. According to the rightThe method of claim 6, wherein the step of assigning a far field pattern f for each subarray _i As a unit directional diagram; according to the arrangement and division of the sub-arrays, the phase center of each sub-array is corrected by referring to the following formula, and finally far field vector synthesis is carried out on far field pattern of all sub-arrays to obtain a final far field radiation pattern F;

in the formula: f is the final directional diagram of the large-aperture phased array antenna;

f _i i =1, 2, \ 8230for the far field pattern of each subarray, n;

k is the wave number, k =2 π/λ, λ is the wavelength;

u＝sin(θ)cos(φ)；

v＝sin(θ)sin(φ)；

x _i ，y _i the relative position of the ith sub-array in the large-aperture phased array antenna.

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