High-precision measurement method and system for zero-depth level uplift of wave-transparent window

Abstract

The invention belongs to the technical field of electromagnetic fields and microwaves, and relates to a high-precision measurement method for zero-depth level uplift of a wave-transparent window. The method comprises the steps that two point source antennas are adopted as two transmitting antennas, superposition of signals of the two transmitting antennas is achieved by adjusting the amplitude ratio and the phase difference of the two transmitting antennas, and an analog transmitting antenna is obtained; the zero-depth level measurement of the receiving antenna is realized by simulating the transmitting antenna, and the zero-depth level rise of the wave-transparent window is obtained by comparing whether the receiving antenna has the zero-depth level value of the wave-transparent window or not. According to the invention, a traditional method that a turntable is adopted to measure an antenna difference pattern to obtain the zero-depth level uplift of the wave-transparent window is abandoned, and the zero-depth level uplift is measured by adopting a mode that amplitude-phase synthesis is carried out on the two-point source antenna to simulate an emission source, so that the test precision of the zero-depth level uplift of the wave-transparent window can be greatly improved; the method can be applied to zero-depth level uplift tests of wave-transparent windows of various amplitude comparison systems.

Description

Technical Field

[0001] The invention belongs to the field of electromagnetic field and microwave technology, and in particular relates to a high-precision measurement method and system for zero-depth level rise of a wave-transmitting window. Background Art

[0002] The zero-depth level rise test is a project of the electrical performance test of the wave-transmitting window. The test method usually adopts the comparison method to compare the zero-depth level of the antenna with or without the wave-transmitting window, and calculate the zero-depth level rise of the wave-transmitting window. When the comparison method is used to test the zero-depth level rise, the movement range and angle step of the test turntable are set in advance. The test turntable moves according to the angle step within the fixed movement range. At the same time, the vector network analyzer records the zero-depth position and zero-depth level of the antenna for the calculation of the zero-depth level rise. The test accuracy of this test method is difficult to guarantee. For antennas with better performance, when the scanning angle interval is 0.001°, the level change of the antenna at the zero-depth position can reach about 12dB. For some test occasions with high precision requirements, such as a test accuracy of 0.2dB, this requires the positioning accuracy of the turntable to be much better than 0.001°, or even 0.0001°, which is difficult to achieve in engineering.

[0003] Therefore, it is necessary to provide a new testing method to improve the accuracy of the zero-depth level rise test of the wave-transmitting window. Summary of the invention

[0004] The purpose of the present invention is to overcome the problem of low test accuracy when using a turntable to test the zero-depth level rise of a wave-transmitting window, and to provide a high-precision measurement method and system for the zero-depth level rise of a wave-transmitting window.

[0005] The technical solution of the present invention is as follows:

[0006] A high-precision measurement method for zero-depth level elevation of a wave-transmitting window comprises the following steps:

[0007] Two point source antennas are used as two transmitting antennas, and the signals of the two transmitting antennas are superimposed by adjusting the amplitude ratio a and the phase difference Φ of the two transmitting antennas to obtain a simulated transmitting antenna;

[0008] The zero-depth level measurement of the receiving antenna is realized by simulating the transmitting antenna. By comparing the zero-depth level values ​​of the receiving antenna with and without the wave-transmitting window, the zero-depth level elevation of the wave-transmitting window is obtained.

[0009] Furthermore, a programmable adjustable attenuator and a programmable phase shifter are provided at the front end of the feed network of one of the two transmitting antennas, and the amplitude ratio a and the phase difference Φ of the two transmitting antennas are adjusted by controlling the programmable attenuator and the programmable phase shifter.

[0010] Furthermore, the accuracy of the programmable adjustable attenuator is required to reach 0.01 dBm, and the accuracy of the programmable phase shifter is required to reach 0.1°.

[0011] Furthermore, the position x0 of the simulated transmitting antenna moves on the X-axis, x0=(x1+x2a 2 +(x1+x2)a*cosΦ) / (a 2 +2a*cosΦ+1), where x1 and x2 are the positions of the two transmitting antennas, and the X axis is the axis where x1 and x2 are located.

[0012] Furthermore, assuming that the distance between the central axes of the two transmitting antennas and the receiving antenna is L, the interchange relationship between the position x0 of the simulated transmitting antenna and the turntable angle θ of the receiving antenna is obtained according to the function tan(θ)=x0 / L, and a vector network analyzer is used to collect the receiving signal of the receiving antenna to obtain the zero-depth level rise of the wave-transmitting window at the test angle.

[0013] Furthermore, the adjusting of the amplitude ratio a and the phase difference Φ of the two transmitting antennas is to adjust both the amplitude ratio a and the phase difference Φ, or to fix the amplitude ratio a and only adjust the phase difference Φ.

[0014] Furthermore, the amplitude ratio a and the phase difference Φ of the two transmitting antennas are adjusted so that the change of the angle θ is less than 0.00001°, thereby meeting the requirement of 0.2 dB of zero-depth level rise test accuracy.

[0015] Furthermore, the zero-depth level measurement of the receiving antenna is realized by simulating the transmitting antenna, and the zero-depth level elevation of the wave-transmitting window is obtained by comparing the zero-depth level value of the receiving antenna with or without the wave-transmitting window, including:

[0016] Adjust the feeding amplitude ratio a of the two transmitting antennas to 2;

[0017] The phase difference Φ is adjusted to change from -1° to 1° with a step of 0.2°, and the zero-depth level value LS(empty) of the receiving antenna without a wave-transmitting window and the zero-depth level value LS(with) of the receiving antenna with a wave-transmitting window are recorded by a vector network analyzer;

[0018] According to the formula LS=LS(band)-LS(space), the zero-depth level rise of the wave-transmitting window is calculated.

[0019] A high-precision measurement system for zero-depth level elevation of a wave-transmitting window comprises two transmitting antennas and one receiving antenna, wherein the two transmitting antennas are two point source antennas; a programmable adjustable attenuator and a programmable phase shifter are arranged at the front end of a feeding network of one of the two transmitting antennas, which are used to adjust the amplitude ratio a and the phase difference Φ of the two transmitting antennas to achieve superposition of signals of the two transmitting antennas, and obtain a simulated transmitting antenna; a vector network analyzer is arranged between the two transmitting antennas and the receiving antenna, which is used to achieve zero-depth level measurement of the receiving antenna through the simulated transmitting antenna, and then the zero-depth level elevation of the wave-transmitting window is obtained by comparing the zero-depth level value of the receiving antenna with or without the wave-transmitting window.

[0020] The present invention uses two point source antennas as transmitting antennas, adjusts the output power and phase of one of the antennas, so that the synthetic signal of the two point source antennas can simulate a simulated antenna moving on the X-axis, and realizes the zero-depth level measurement of the antenna to be tested (receiving antenna) by simulating the movement of the antenna on the X-axis. By comparing whether the antenna to be tested has a wave-transmitting window, the zero-depth level rise of the wave-transmitting window is obtained. This method can greatly improve the test accuracy of the zero-depth level rise, and can be used for the rapid and high-precision measurement of the zero-depth level rise of the wave-transmitting window of the amplitude comparison system, and has a good prospect for engineering application.

[0021] The beneficial effects of the present invention compared with the prior art are as follows:

[0022] (1) The present invention abandons the traditional method of using a turntable to measure the antenna difference radiation pattern to obtain the zero-depth level rise of the wave-transmitting window, and adopts the method of performing amplitude-phase synthesis of two point sources to simulate the transmitting source to measure the zero-depth level rise, which can greatly improve the test accuracy of the zero-depth level rise of the wave-transmitting window and solve the problem of low test accuracy of the zero-depth level rise of the wave-transmitting window.

[0023] (2) The technical solution of the present invention can improve the test accuracy of the zero-depth level rise of the wave-transmitting window to 0.2 dB, and has good engineering application prospects.

[0024] (3) The technical solution of the present invention can be applied to the zero-depth level rise test of various amplitude ratio system wave-transmitting windows. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is a connection schematic diagram of the high-precision measurement system for zero-depth level raising of the wave-transmitting window of the present invention.

[0026] Figure 2 It is a schematic diagram of the rough measurement of the antenna of the present invention at zero depth in 1° steps.

[0027] Figure 3 It is a schematic diagram of the antenna zero depth of the present invention being measured in 0.001° steps.

[0028] Figure 4 It is the zero-depth level rise test curve of the wave-transmitting window of the present invention. DETAILED DESCRIPTION

[0029] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below through specific embodiments and drawings.

[0030] This embodiment is a high-precision measurement method of zero-depth level raising of a wave-transmitting window based on power and phase adjustment. Taking the zero-depth level raising test of a wave-transmitting window as an example, the detailed implementation method of the test steps is described.

[0031] The zero-depth level rise test method of the present invention abandons the traditional measurement method of using a turntable to measure the zero-depth level rise of the wave-transmitting window. Figure 1 As shown, first, two point source antennas are used as transmitting antennas at the transmitting end, namely transmitting antennas 1 and 2. The distance between the two antennas should not be too small to avoid mutual coupling between the antennas. About 3.5 meters is more appropriate. The position of transmitting antenna 1 is recorded as x1, and the position of transmitting antenna 2 is recorded as x2. The feeding power of the two transmitting antennas is kept consistent. A programmable adjustable attenuator and a programmable phase shifter are used at the front end of the feeding network of one of the transmitting antennas (transmitting antenna 2). The accuracy of the programmable adjustable attenuator is required to reach 0.01dBm, and the accuracy of the programmable phase shifter is required to reach 0.1°. Figure 1 The power divider in the receiver is used to distribute power to the two transmitting antennas. The receiving antenna is mounted on the receiving turntable ( Figure 1 The programmable attenuator and the programmable phase shifter are controlled to adjust the amplitude ratio a and the phase difference Φ of the two transmitting antennas. By adjusting a and Φ, the signals of the two transmitting antennas can be superimposed and are equivalent to the signal emitted by a simulated point source antenna at a certain position. The position x0 = (x1 + x2a 2 +(x1+x2)a*cosΦ) / (a 2 +2a*cosΦ+1). By adjusting a and Φ, a simulated antenna (i.e. Figure 1 The position x0 of the simulated transmitting antenna 0) in the X-axis (i.e. Figure 1 Assuming that the distance between the central axes of the transmitting and receiving antennas is L, the interchange relationship between the position x0 of the simulated antenna and the rotation angle θ of the receiving antenna turntable can be obtained according to the function tan(θ)=x0 / L. At the same time, the receiving signal of the receiving antenna is collected by a vector network analyzer to obtain the zero-depth level rise of the wave-transmitting window at the test angle.

[0032] In this embodiment, the test azimuth angle of the wave-transmitting window is 0° normal incidence, the zero-depth level rise test accuracy requirement is 0.2dB, and the distance between the transmitting and receiving antennas is R=20m. Figure 2 It can be seen that the test angle step (i.e. the change in the angle θ) is 1°, and the zero depth level error caused by the angle error is very large and cannot meet the test requirements. Figure 3 It can be seen that the test angle step is 0.001°, and the zero-depth level error caused by the angle error is 16dB. Assuming that the zero-depth level is linear within the range of 0.001°, when the angle step reaches 0.00001°, the test accuracy can reach 0.16dB, which can meet the test requirement of 0.2dB. It is necessary to adjust the amplitude ratio a and the phase difference Φ so that the change of the angle θ is less than 0.00001°. Here, for the convenience of control, a can be fixed and only Φ can be adjusted.

[0033] This embodiment uses Figure 1 The test system shown is tested, and the specific test steps are as follows:

[0034] A. Install the transmitting antenna (including two point source antennas 1 and 2) and the receiving antenna so that the polarization directions of the two antennas are consistent with the test requirements;

[0035] B. Connect the connecting cable between the transceiver antenna and the test instrument;

[0036] C. Adjust the feeding power of the programmable adjustable attenuator so that the feeding amplitude ratio a of the two point source antennas is 2;

[0037] D. Adjust the phase difference Φ by adjusting the programmable phase shifter. When the phase difference Φ changes by 0.2°, according to the formula for the relationship between x0, Φ and θ mentioned above, it can be concluded that the change in angle θ is 0.0000045°, which can meet the test accuracy requirements. At this time, adjust the phase difference Φ from -1° to 1°, with a phase difference step of 0.2°, and record the zero depth level value LS (null) of the receiving antenna (without the wave-transmitting window) through the vector network analyzer;

[0038] E. Bring a wave-transmitting window, e.g. Figure 1 The rectangular wave-transmitting window in the middle is repeated in step D, and the zero-depth level value LS (band) of the receiving antenna is recorded by a vector network analyzer;

[0039] F. According to the formula LS = LS (with) - LS (empty), the zero depth level rise of the wave-transmitting window is obtained, see Figure 4 shown.

[0040] The present invention adopts the method of adjusting the amplitude and phase feeding difference of two point source antennas to perform the zero-depth level rise test of the wave-transmitting window, which eliminates the problem that the turntable test accuracy is difficult to meet the test requirements, can greatly improve the test accuracy of the zero-depth level rise, and can be used for high-precision measurement of the zero-depth level rise of the wave-transmitting window of the amplitude comparison system, and has good engineering application prospects.

[0041] The above is only a specific embodiment of the present invention and does not limit the present invention in any form. Any simple modification or equivalent change made to the above embodiment based on the design method of the invention is still within the protection scope of the technical solution of the present invention.

Claims

1. A high-precision measurement method for zero-depth level elevation of a wave-transmitting window, characterized in that: The following steps are involved: Two point source antennas are used as two transmitting antennas, and the signals of the two transmitting antennas are superimposed by adjusting the amplitude ratio a and the phase difference Φ of the two transmitting antennas to obtain a simulated transmitting antenna; The zero-depth level measurement of the receiving antenna is realized by simulating the transmitting antenna. By comparing the zero-depth level values ​​of the receiving antenna with and without the wave-transmitting window, the zero-depth level elevation of the wave-transmitting window is obtained.

2. The method according to claim 1, characterized in that A programmable adjustable attenuator and a programmable phase shifter are arranged at the front end of the feed network of one of the two transmitting antennas, and the amplitude ratio a and the phase difference Φ of the two transmitting antennas are adjusted by controlling the programmable attenuator and the programmable phase shifter.

3. The method according to claim 2, characterized in that The accuracy of the programmable adjustable attenuator is required to reach 0.01 dBm, and the accuracy of the programmable phase shifter is required to reach 0.1°.

4. The method according to claim 1, characterized in that The position x0 of the simulated transmitting antenna moves on the X-axis, x0=(x1+x2a 2 +(x1+x2)a*cosΦ) / (a 2 +2a*cosΦ+1), where x1 and x2 are the positions of the two transmitting antennas, and the X axis is the axis where x1 and x2 are located.

5. The method according to claim 4, characterized in that The distance between the central axes of the two transmitting antennas and the receiving antenna is L. The interchange relationship between the position x0 of the simulated transmitting antenna and the turntable angle θ of the receiving antenna is obtained according to the function tan(θ)=x0 / L, and the receiving signal of the receiving antenna is collected by a vector network analyzer to obtain the zero-depth level rise of the wave-transmitting window at the test angle.

6. The method according to claim 1, characterized in that The adjustment of the amplitude ratio a and the phase difference Φ of the two transmitting antennas is to adjust both the amplitude ratio a and the phase difference Φ, or to fix the amplitude ratio a and only adjust the phase difference Φ.

7. The method according to claim 1, characterized in that The amplitude ratio a and phase difference Φ of the two transmitting antennas are adjusted so that the change in angle θ is less than 0.00001°, thereby meeting the requirement of 0.2dB accuracy for zero-depth level rise test.

8. The method according to claim 7, characterized in that The zero-depth level measurement of the receiving antenna is realized by simulating the transmitting antenna, and the zero-depth level elevation of the wave-transmitting window is obtained by comparing the zero-depth level value of the receiving antenna with or without the wave-transmitting window, including: Adjust the feeding amplitude ratio a of the two transmitting antennas to 2; The phase difference Φ is adjusted to change from -1° to 1° with a step of 0.2°, and the zero-depth level value LS(empty) of the receiving antenna without a wave-transmitting window and the zero-depth level value LS(with) of the receiving antenna with a wave-transmitting window are recorded by a vector network analyzer; According to the formula LS=LS(band)-LS(space), the zero-depth level rise of the wave-transmitting window is calculated.

9. A high-precision measurement system for zero-depth level elevation of a wave-transmitting window, characterized in that: It includes two transmitting antennas and one receiving antenna, wherein the two transmitting antennas are two point source antennas; A programmable adjustable attenuator and a programmable phase shifter are provided at the front end of the feed network of one of the two transmitting antennas, which are used to adjust the amplitude ratio a and the phase difference Φ of the two transmitting antennas to achieve the superposition of the signals of the two transmitting antennas, thereby obtaining a simulated transmitting antenna; A vector network analyzer is set between the two transmitting antennas and the receiving antenna to realize the zero-depth level measurement of the receiving antenna by simulating the transmitting antenna, and then the zero-depth level elevation of the wave-transmitting window is obtained by comparing the zero-depth level value of the receiving antenna with and without the wave-transmitting window.

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