Spherical near-field test system and test method

Abstract

The present invention discloses a spherical near-field test system and a test method, which belong to the field of antenna test technology. The system comprises a probe array, an azimuth turntable, a receiver and a control extension. The antenna to be tested is fixed on the azimuth turntable, the receiver is used to provide a signal to the antenna to be tested, and the control extension is used to control the movement of the azimuth turntable. The probe array is a spiral structure, which comprises a plurality of microwave probes, and the adjacent microwave probes are spaced apart in a pitch direction according to a first angle interval Δ θ Arrange, in the azimuth direction according to the second angle interval #imgabs0#, #imgabs1##imgabs2# are fixed angle intervals, N p is the number of microwave probes in the probe array. The present invention can ensure that the azimuth angle of each detection is completely consistent during the test process by designing a spiral structure, thereby ensuring both the test speed and the test positioning accuracy.

Description

Technical Field

[0001] The present invention relates to the technical field of antenna testing, and in particular to a spherical near-field testing system and a testing method. Background Art

[0002] The spherical near-field test system is a system used to measure the radiation performance of antennas. It is usually composed of a near-field test sampling rack and a radio frequency instrument subsystem. The spherical near-field test system can be divided into a single-probe test system and a multi-probe test system. The single-probe test system uses a single microwave probe to complete the sampling of the entire spherical space; the multi-probe test system uses multiple microwave probes plus a matrix switch to complete the sampling of the entire spherical space. Compared with other near-field test systems, the spherical near-field can obtain antenna performance in three-dimensional space, and the test range is wider; at the same time, due to its completely symmetrical structure, it is easy to implement probe compensation and it is easier to use broadband probes; the spherical near-field test system with multiple sampling probes plus electronic switch switching can increase the antenna test speed by an order of magnitude.

[0003] In the existing multi-probe spherical near-field test system, in order to improve the near-field test speed, multiple probes with the same electrical properties are used to form a probe array. Each probe in the probe array is in the same position in the azimuth angle and is arranged at equal angles in the pitch direction. Sampling of all probe arrays is completed at each azimuth angle by switching the electronic switch channel.

[0004] Therefore, the multi-probe spherical near-field test system has two working modes during the sampling process: the first is the stationary sampling mode, which requires the azimuth turntable to be in a completely stopped state to complete the sampling work of each probe; the second is the motion sampling mode, in which the azimuth turntable completes the sampling of the probe array during uniform motion.

[0005] For the stationary sampling mode, each point in the azimuth direction needs to complete the "start-acceleration-deceleration-stop" cycle. The test cycle of this mode is long, which is not conducive to the rapid testing of the antenna. For the motion sampling mode, because the sampling process requires a time interval, the azimuth position of the antenna under test changes when each probe is sampling, which will cause a large test error.

[0006] Therefore, the shortcomings of antenna testing technology under spherical near-field conditions are:

[0007] (1) While pursuing test accuracy, the test speed will decrease, especially when measuring large-sized antennas.

[0008] (2) Under the premise of pursuing test speed, the test error will increase, especially when there are a large number of probes in the probe array or a large number of sampling points.

[0009] In the related art, the Chinese invention patent application with publication number CN113985150A discloses an air interface test system and method based on the atomic coherence effect, which includes: on a circular scanning bracket in a microwave darkroom, a plurality of prism-type atomic antenna probes are evenly arranged at specific angle intervals to form a circular atomic probe array according to the requirements of the sampling theorem, and the circular atomic probe array is connected to the optical fiber beam splitter through an optical fiber. The antenna under test is placed on a turntable and the phase center of the antenna under test is ensured to be at the center of the scanning bracket. The antenna under test serves as a transmitting antenna, and the atomic microwave electric field meter sequentially controls the prism-type atomic antenna probe to complete the data collection of each receiving channel. The control computer controls the antenna turntable to rotate the antenna under test to complete the three-dimensional spherical near-field data collection; the collected spherical near-field data is transformed into near-far field to obtain three-dimensional far-field data.

[0010] However, this solution uses the principle of atomic coherence effect to achieve air interface measurement. The test probe using atomic coherence effect can only realize the transmission test of the antenna under test, but the test probe cannot transmit microwave signals, the application range is narrow, and a more conventional uniformly distributed probe is used. Summary of the invention

[0011] The technical problem to be solved by the present invention is how to balance the test speed and test accuracy of spherical near-field testing.

[0012] The present invention solves the above technical problems through the following technical means:

[0013] On the one hand, the present invention provides a spherical near-field test system, the system comprising a probe array, an azimuth turntable, a receiver and a control extension, the antenna under test is fixed on the azimuth turntable, the receiver / signal source is used to provide a signal to the antenna under test, and the control extension is used to control the movement of the azimuth turntable;

[0014] The probe array is a spiral structure, which includes a plurality of microwave probes, and adjacent microwave probes are spaced at a first angle Δ in the pitch direction. θ Arrange, in azimuth direction according to the second angle interval arrangement, For fixed angle intervals, is the maximum available sampling interval for angles, N p is the number of microwave probes in the probe array.

[0015] The present invention designs a probe array with a spiral structure, in which adjacent probes in the probe array are arranged at a first angle in the pitch direction and at a second angle in the azimuth direction. When the probe array is used for spherical near-field testing, there is no need for the sampling frame to maintain a stationary mode during the test calibration process. In the test process of the traditional upright probe array, the position of the azimuth turntable changes when each probe is sampled, so the azimuth angle position of the antenna under test is different when each probe is sampled. However, the present invention, through the designed spiral structure, can ensure that the azimuth angle of each detection is completely consistent during the test process, thereby ensuring both the test speed and the test positioning accuracy. Compared with the existing near-field antenna testing technology, the present invention solves two contradictory problems: sampling in motion and sampling position error.

[0016] Furthermore, the number of the microwave probes satisfies the following formula:

[0017] N≤N p *N s

[0018] Where N is the number of test points at the first angle, N s is the number of tests, N p is the number of probes in the probe array.

[0019] Furthermore, the first angular interval Δ θ Satisfies the following formula:

[0020]

[0021] Among them, θ max is the maximum value of the pitch angle range of the probe array.

[0022] Furthermore, the azimuth turntable is provided with a mounting hole for mounting the antenna under test, and the azimuth turntable includes a rotating mechanism and a lifting mechanism, the lifting mechanism is used to control the lifting and lowering of the antenna under test in the vertical direction, and the rotating mechanism is used to control the antenna under test to rotate at a uniform speed along the azimuth direction.

[0023] Furthermore, the probe array is installed on a rotating guide rail, and the rotating guide rail is used to adjust the pitch angle of each microwave probe in the probe array.

[0024] Furthermore, the control extension includes:

[0025] The parameter setting module is used to set the test parameters, including the fixed angle interval of the test system. and frequency of testing;

[0026] The sampling time acquisition module is used to obtain the time t required for the receiver to sample a sampling point at the current test frequency.p ;

[0027] The sampling point working time calculation module is used to calculate the working time of the sampling point according to t p Set the working time t at the sampling point s , where t s >t p ;

[0028] A rotation speed calculation module is used to calculate the rotation speed of the azimuth turntable. N p is the number of microwave probes in the probe array;

[0029] The test module is used to test the working time t of the probe sampling point according to the working time t s , complete the sampling test of microwave probe at each location point.

[0030] Furthermore, the control sub-machine is connected to the azimuth turntable and the rotating guide rail respectively via a motion controller, and the control sub-machine includes:

[0031] The motion control module is used to control the center of the antenna under test to move to the center of the test sphere through the lifting mechanism; and the rotation mechanism is used to control the antenna under test to rotate at a uniform speed along the azimuth direction, and the rotation speed is

[0032] In addition, the present invention also proposes a spherical near field testing method, the method comprising:

[0033] Set the test parameters, including the angle fixed interval of the test system and the receiver sampling time t p ;

[0034] Using the receiver / signal source to provide a radio frequency signal to the antenna under test, so that the antenna under test transmits a signal, and the antenna under test is installed on an azimuth turntable;

[0035] According to the receiver sampling time t p Determine the sampling point working time t s :t s >t p ;

[0036] Calculate the rotation speed of the azimuth turntable And according to the rotation speed Control the azimuth turntable to rotate at a uniform speed along the azimuth direction, N p is the number of microwave probes in the probe array;

[0037] According to the sampling time interval t of the probe s, controlling each probe in the probe array to perform sampling testing.

[0038] The advantages of the present invention are:

[0039] (1) The present invention designs a probe array with a spiral structure, in which adjacent probes are arranged at a first angle in the pitch direction and at a second angle in the azimuth direction. When the probe array is used for spherical near-field testing, the sampling frame does not need to maintain a stationary mode during the test calibration process. In the test process of a traditional upright probe array, the position of the azimuth turntable changes when each probe is sampling, so the azimuth angle position of the antenna under test is different when each probe is sampling. However, the present invention, through the spiral structure designed, can ensure that the azimuth angle of each detection is completely consistent during the test process, thereby ensuring both the test speed and the test positioning accuracy. Compared with the existing near-field antenna testing technology, the present invention solves two contradictory problems: sampling in motion and sampling position error.

[0040] (2) By controlling the sampling time interval of the receiver, each probe can complete data sampling at the same azimuth angle. This feature shortens the test cycle compared to existing test methods, greatly improves test efficiency, and improves the test output of the multi-probe spherical near-field test system.

[0041] (3) The sampling position error produced by the present invention is significantly smaller than that of the existing testing methods.

[0042] Additional aspects and advantages of the present invention will be given in part in the following description and in part will be obvious from the following description, or will be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Figure 1 is a schematic structural diagram of a spherical near-field test system in a first embodiment of the present invention;

[0044] Figure 2 is a schematic diagram of the angle position relationship of the probe array in the first embodiment of the present invention;

[0045] Figure 3 is a schematic diagram of an azimuth turntable in a first embodiment of the present invention;

[0046] Figure 4 is a schematic flow chart of a spherical near-field testing method in a second embodiment of the present invention;

[0047] Figure 5 It is a schematic diagram of the overall process of the spherical near-field testing method in the second embodiment of the present invention.

[0048] In the figure:

[0049] 10-probe array; 20-azimuth turntable; 30-receiver / signal source; 40-control extension; 50-motion controller; 60-tested antenna; 70-rotating guide rail; 80-microwave probe. DETAILED DESCRIPTION

[0050] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described in combination with the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0051] like Figures 1 to 3 As shown, the first embodiment of the present invention provides a spherical near-field test system, the system comprising a probe array 10, an azimuth turntable 20, a receiver / signal source 30 and a control extension 40, the antenna 60 to be tested is fixed on the azimuth turntable 20, the receiver / signal source 30 is used to provide a signal to the antenna 60 to be tested, and the control extension 40 is used to control the movement of the azimuth turntable 20;

[0052] The probe array 10 is a spiral structure, which includes a plurality of microwave probes 80, and adjacent microwave probes 80 are spaced apart at a first angle Δ in the pitch direction. θ Arrange, in azimuth direction according to the second angle interval arrangement, For fixed angle intervals, is the maximum available sampling interval for angles, N p is the number of microwave probes 80 in the probe array 10 .

[0053] Furthermore, the receiver / signal source 30 is responsible for providing RF signal output for the test system, receiving sampled RF signals, and recording the vector value of the RF signal. The receiver / signal source 30 used in this embodiment is similar to other common test systems and adopts universal instruments; the azimuth turntable 20 can be lifted, moved, rotated and turned to adjust the position of the antenna under test 60; the control extension 40 is used to control the lifting and rotation of the azimuth turntable 20, thereby adjusting the position and rotation speed of the antenna under test 60, and controlling the probe array 10 to complete data collection of each connector channel, and controlling the receiver to sample according to the time sequence to complete the spherical near field test.

[0054] It should be noted that, unlike the traditional upright probe array 10 in the spherical near field test process, the position of the azimuth turntable 20 of each probe in the upright probe array 10 changes when sampling, so the azimuth angle position of each probe when sampling is different; and the spiral structure designed by the present invention can ensure that the azimuth angle of each detection is completely consistent during the test process, which not only ensures the test speed, but also ensures the test positioning accuracy, and there is no need for the sampling frame to maintain the stationary mode during the test calibration process. Compared with the existing near-field antenna test technology, this embodiment solves two contradictory problems: sampling in motion and sampling position error.

[0055] In one embodiment, the required number of test points is first calculated according to the size of the antenna 60 under test and the test frequency of the antenna 60 under test, and then the sampling times are set according to the number of test probes:

[0056]

[0057] Where: λ is the wavelength corresponding to the measurement frequency, r is the minimum sphere diameter surrounding the antenna under test, D is a constant, usually between 3-10, and N is the number of test points at the first angle.

[0058] After obtaining the number of test points at the first angle, according to the number of probes N p To configure the number of tests N s So that:

[0059] N≤N p *N s

[0060] Where N is the number of test points at the first angle, N s is the number of tests.

[0061] It should be noted that, specifically in this embodiment, N s Usually 1, i.e. one measurement.

[0062] In one embodiment, the pitch angle interval Δ θ It is a fixed value of hardware design and can be calculated based on the pitch angle range of the probe array 10 and the number of probes:

[0063]

[0064] Where: θ max is the maximum pitch angle range of the probe array 10, N p is the number of probes.

[0065] In one embodiment, the calculation formula for the maximum available sampling interval of angle is:

[0066]

[0067] In one embodiment, a mounting hole for mounting the antenna under test 60 is provided on the azimuth turntable 20, and the azimuth turntable 20 includes a rotating mechanism and a lifting mechanism, the lifting mechanism is used to control the vertical lifting of the antenna under test 60, and the rotating mechanism is used to control the uniform rotation of the antenna under test 60 along the azimuth direction.

[0068] It should be noted that the azimuth turntable 20 has a one-dimensional azimuth rotation function and a height lifting function, and a mounting hole for mounting the antenna 60 under test is provided on the rotating platform, and the antenna 60 under test is fixed on the rotating platform through the mounting hole. During the test, the height lifting device is adjusted so that the center of the antenna 60 under test is located at the center of the test sphere; then, driven by the azimuth turntable 20, the antenna 60 under test rotates at a constant speed along the azimuth direction.

[0069] Specifically, the azimuth rotating table can be raised and lowered by a hand-cranked device plus a screw rod, and can be rotated by a combination of a servo motor and a gear reducer.

[0070] In one embodiment, the probe array 10 is mounted on a rotating guide rail 70 , and the rotating guide rail 70 is used to adjust the pitch angle of each microwave probe 80 in the probe array 10 .

[0071] It should be noted that when the number of probes in the probe array 10 is large and the arrangement is dense, the pitch angle of the probes can be adjusted by rotating the guide rail 70 .

[0072] In one embodiment, the control sub-machine 40 is connected to the azimuth turntable 20 and the rotating guide rail 70 respectively via the motion controller 50, and the control sub-machine 40 includes:

[0073] The motion control module is used to control the center of the antenna under test 60 to move to the center position of the test sphere through the lifting mechanism; and is used for the rotation mechanism to control the antenna under test 60 to rotate at a uniform speed along the azimuth direction.

[0074] In one embodiment, the control extension 40 includes:

[0075] The parameter setting module is used to set the test parameters, including the angle fixed interval of the test system and test frequency, where is the maximum available sampling interval for angles.

[0076] The sampling time acquisition module is used to obtain the receiver sampling time t at the current test frequency. p ;

[0077] The sampling point working time calculation module is used to calculate the sampling time of the receiver according to the sampling time t pDetermine the sampling point working time t s , where t s >t p ;

[0078] A rotation speed calculation module, used to calculate the rotation speed of the azimuth turntable 20 N p is the number of microwave probes 80 in the probe array 10 .

[0079] It should be noted that the calculated rotation speed of the azimuth turntable 20 should be less than the fastest rotation speed of the azimuth turntable 20 .

[0080] Test module for rotating at said speed Control the rotation of the azimuth turntable and adjust the sampling time of the probe sampling point according to the working time t s The receiver / signal source is controlled to perform sampling to complete the sampling test of the microwave probe at each position point.

[0081] It should be noted that, compared with the existing near-field antenna measurement technology, this embodiment solves two contradictory problems: sampling during motion and sampling position error.

[0082] (1) Sampling during motion:

[0083] Since the probe array 10 includes a fixed azimuth angle interval during the design process Therefore, during the test, if the appropriate turntable movement speed is set By controlling the working time t of the sampling point of the receiver 30 s The time interval allows each probe to complete data sampling at the same azimuth angle. This feature shortens the test cycle compared to existing test methods, greatly improves test efficiency, and improves the test output of the multi-probe spherical near-field measurement system.

[0084] (2) Sampling position error:

[0085] Due to the special design of the probe array 10 and the test method design, the position error Δ p The position error is calculated by the difference between the actual position value and the theoretical value. Using the scheme designed in this embodiment, the position error is calculated by the sampling time error Δ t , turntable movement speed And the bracket processing error Δ m Determine, that is:

[0086]

[0087] Compared with the existing test system, the position error is determined by the sampling time ts With movement speed and bracket processing error Δ m Therefore, the sampling error of the present invention is significantly reduced in the test, and the error calculation formula is as follows:

[0088]

[0089] Typically, Δ t Less than 1ms, t s Less than 20ms, and the number of probes n is usually selected between [32, 64, 128]; obviously, E 2 (n) The calculated error is significantly higher than E 1 , that is to say, the sampling position error generated by applying the design scheme of this embodiment is significantly smaller than that of the existing test method.

[0090] In addition, if Figure 4 As shown, the second embodiment of the present invention provides a spherical near field testing method, the method comprising the following steps:

[0091] S10, setting test parameters, the test parameters including the angle fixed interval of the test system and the receiver sampling time t p .

[0092] S20, using a signal source to provide a radio frequency signal to the antenna under test, so that the antenna under test transmits a signal, and the antenna under test is installed on an azimuth turntable.

[0093] S30, according to the receiver sampling time t p Set the working time t at the sampling point s , where t s >t p ;

[0094] S40, calculating the rotation speed of the azimuth turntable And according to the rotation speed Control the azimuth turntable to rotate at a uniform speed along the azimuth direction, N p is the number of microwave probes in the probe array.

[0095] S50, according to the sampling point working time t of the probe s , controlling each probe in the probe array to perform sampling testing.

[0096] In this embodiment, the rotation speed of the orientation turntable in the test system is designed. and the sampling working time t of the receiver 30 s ,The application of this test method can ensure that the system test speed and test accuracy are in the optimal state.

[0097] In one embodiment, if Figure 5 As shown, the step S50 includes:

[0098] Determine whether all probes in the probe array have completed the sampling test of the current sampling point;

[0099] If not, the receiver samples and waits for the sampling period t s Then re-judge;

[0100] If yes, proceed to the next sampling point for sampling test.

[0101] In one embodiment, the method comprises:

[0102] Controlling the azimuth turntable to move the center of the antenna under test to the center position of the test sphere;

[0103] The azimuth turntable is controlled to make the antenna under test rotate at a uniform speed along the azimuth direction.

[0104] It should be noted that other embodiments or implementation methods of the spherical near-field testing method of the present invention can refer to the above-mentioned system embodiments, which will not be repeated here.

[0105] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

[0106] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of the present invention, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0107] Although the embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations of the present invention. A person skilled in the art may change, modify, replace and vary the above embodiments within the scope of the present invention.

Claims

1. A spherical near-field test system, characterized in that: The system includes a probe array, an azimuth turntable, a receiver / signal source and a control extension, the antenna under test is fixed on the azimuth turntable, the receiver / signal source is used to provide a signal to the antenna under test, and the control extension is used to control the movement of the azimuth turntable; The probe array is a spiral structure, which includes a plurality of microwave probes, and adjacent microwave probes are spaced at a first angle in the pitch direction. Arrange, in azimuth direction according to the second angle interval arrangement, , For fixed angle intervals, , is the maximum available sampling interval for angles, is the number of microwave probes in the probe array; The control extension includes: The parameter setting module is used to set the test parameters, including the fixed angle interval of the test system. and frequency of testing; Sampling time acquisition module, used to obtain the receiver sampling time at the current test frequency ; Sampling point working time calculation module, used to calculate the sampling time of the receiver Determine the working hours of the sampling point ,in ; A rotation speed calculation module is used to calculate the rotation speed of the azimuth turntable. : , is the number of microwave probes in the probe array; Test module for rotating at said speed Control the rotation of the azimuth turntable and adjust the sampling time of the probe sampling point according to the working time of the probe sampling point. The receiver / signal source is controlled to perform sampling to complete the sampling test of the microwave probe at each position point.

2. The spherical near-field test system according to claim 1, characterized in that: The number of microwave probes satisfies the following formula: in, is the number of test points at the first angle, is the number of tests.

3. The spherical near-field test system according to claim 1, characterized in that: The first angular interval Satisfies the following formula: in, is the maximum value of the pitch angle range of the probe array.

4. The spherical near-field test system according to claim 1, characterized in that: The azimuth turntable is provided with a mounting hole for mounting the antenna under test, and the azimuth turntable includes a rotating mechanism and a lifting mechanism, the lifting mechanism is used to control the lifting of the antenna under test in the vertical direction, and the rotating mechanism is used to control the antenna under test to rotate at a uniform speed along the azimuth direction.

5. The spherical near-field test system according to claim 4, characterized in that: The probe array is installed on a rotating guide rail, and the rotating guide rail is used to adjust the pitch angle of each microwave probe in the probe array.

6. The spherical near-field test system according to claim 5, characterized in that: The control sub-machine is connected to the azimuth turntable and the rotating guide rail respectively via a motion controller, and the control sub-machine comprises: The motion control module is used to control the center of the antenna under test to move to the center position of the test sphere through the lifting mechanism; and is used for the rotation mechanism to control the antenna under test to rotate at a uniform speed along the azimuth direction.

7. A spherical near-field testing method based on the spherical near-field testing system according to any one of claims 1 to 6, characterized in that: The method comprises: Set test parameters including fixed angle intervals of the test system and receiver sampling time ; Using a receiver / signal source to provide a radio frequency signal to the antenna under test so that the antenna under test transmits a signal, and the antenna under test is installed on an azimuth turntable; According to the receiver sampling time Determine the working hours of the sampling point : ; Calculate the rotation speed of the azimuth turntable , and according to the rotation speed Control the azimuth turntable to rotate at a uniform speed along the azimuth direction, , is the number of microwave probes in the probe array; According to the sampling time interval of the probe , controlling each probe in the probe array to perform sampling testing.

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