CN103630761A - Multi-probe spherical near field channel calibration device and method - Google Patents

Abstract

The invention provides a multi-probe spherical near field channel calibration device and method. The device comprises a tool, a rotary shaft, a telescopic arm, an orienting antenna, a laser range finder, a first rotary table control system and a second rotary table control system; the tool is arranged on a rotary table and is provided with the rotary shaft; the telescopic arm is arranged on the rotary shaft and is provided with the orienting antenna; the orienting antenna is provided with the laser ranger finder; the first rotary control system is arranged to be connected with the tool and is used for controlling the tool to move left and right or up and down; the second rotary table control system is connected with the rotary table and is used for controlling the rotary table. By adopting the scheme, the orienting horn antenna is adopted as the calibration antenna to precisely calibrate the multi-probe spherical near field measuring data of the antenna, and the influence to the antenna performance caused by a backward ground when an omnidirectional antenna is used is avoided.

Description

A multi-probe spherical near-field channel calibration device and method

technical field

The invention belongs to the technical field of spherical near-field channel calibration, and in particular relates to a multi-probe spherical near-field channel calibration device and method.

Background technique

Antenna measurement comes along with antenna design, and is an important means to guide antenna design and verify antenna performance. In the field of antenna measurement, spherical near-field testing is an important means of antenna testing. The principle is: at a distance of several lambdas away from the antenna to be tested, use a probe with known electrical characteristics on the curved surface of the near area of the antenna to be tested. Scan and sample the amplitude and phase data of the electromagnetic field, and then calculate the electrical characteristics of the far field of the antenna under test through rigorous mathematical transformation. For a spherical surface, the final scanning surface of the probe is a spherical surface.

For the spherical surface test, in order to obtain comprehensive information about the antenna to be tested, many points are required to be sampled on the spherical surface. The traditional method of measuring and sampling with a single probe combined with mechanical movement has the disadvantage of slow test speed and time-consuming complete scanning of the entire spherical surface. Shortcomings such as length and low efficiency.

In order to reduce test time and improve test efficiency, people use the development idea of phased array radar to develop a multi-probe spherical near-field test system that replaces traditional mechanical scanning with multi-probe electronic scanning. The technical block diagram is shown in Figure 1. Its principle is: on the arc-shaped track 20 surrounding the antenna to be tested, a number of measuring probes 21 are arranged at certain angular intervals according to the requirements of the sampling theorem, and the measuring probes are connected to the switch matrix 22 composed of electronic switches through cables; The antenna 23 is fixed on the turntable 24 and ensures that the phase center of the antenna is on the center of the circle; the antenna 23 to be tested radiates the signal generated by the vector network analyzer 25, and the system controls the switch matrix 22 to switch between each receiving probe, and through the vector network The analyzer 25 collects the receiving data of each channel; the system controls the rotation of the antenna turntable 24, and collects the data of each receiving probe 21 at each rotation angle to complete the collection of spherical data, and then completes the test after subsequent processing. According to the above test principle, it can be seen that for the multi-probe spherical near-field test, since the electronic switch scanning control method is used on the arc surface instead of the traditional mechanical scanning method, the measurement speed can be significantly improved.

For a multi-probe system, multi-probes form multiple channels. Since there are differences in consistency between the channels from the probe through the cable to the output port of the switch matrix in terms of probes, cables, and switch channels, these channels The physical differences between them form different amplitude and phase characteristics of each channel, so that the influence of channel differences is superimposed on the collected near-field data. For spherical near-field measurement technology, accurate antenna near-field amplitude and phase data can reconstruct accurate far-field information. Therefore, for a multi-probe spherical near-field test system, accurate calibration of channel amplitude and phase errors is required. , to eliminate the influence of each channel is the key and basis for accurate testing.

In order to calibrate the multi-probe test channel and eliminate channel factors, the commonly used calibration method is to use an omnidirectional antenna for calibration. The principle is to use an omnidirectional antenna to replace the antenna under test in the system shown in Figure 1, and set its phase center to At the center of the arc, since the amplitude and phase of the omnidirectional antenna are consistent in all directions, in this case, use a vector network analyzer to collect the amplitude and phase data of each probe receiving channel, and use any one of the channel data as a reference , the error data of other channels can be obtained, which characterizes the amplitude-phase consistency characteristics of each channel. Using the error data, the system can correct the original data of the antenna under test and complete the calibration work.

Calibration using omnidirectional antennas, since omnidirectional antennas are isotropic, is very suitable for channel calibration of this multi-channel spherical near-field system. Usually, half-wave arrays are used as calibration antennas. When the calibration antenna is placed to maximize the direction diagram When the value surface coincides with the surface of the scanning frame of the system, multiple probes can be used to scan it once to obtain channel data. This method is faster and more convenient. However, the omnidirectional antenna has strong backward radiation. When the antenna is placed on the turntable, the distance from the ground is relatively close. When the ground is not treated, or the performance of the absorbing material is not good, the reflection of the ground will affect the omnidirectional The performance of the antenna is seriously affected, and it is no longer the characteristic of consistent amplitude and phase in all directions, so it cannot be used for calibration. In addition, there are also high requirements for the consistency of omnidirectional antennas in all directions.

Therefore, there are defects in the prior art and need to be improved.

Contents of the invention

The technical problem to be solved by the present invention is to provide a multi-probe spherical near-field channel calibration device and method for the deficiencies of the prior art.

Technical scheme of the present invention is as follows:

A method for calibrating a multi-probe spherical near-field channel, comprising the following steps:

Step 1: set the horn antenna as the transmitting antenna, and several measuring probes as the receiving antenna, and set the E plane or H plane of the horn antenna to be located in the θ plane of the spherical coordinates;

Step 2: Fix the fixture with the laser range finder on the surface of the horn antenna, control the turntable by the second turntable control system, make the E or H plane of the horn antenna into the scanning plane, and adjust the telescopic arm to point to a measurement Probe, set the beam of the laser rangefinder on the horn antenna to point to the center of a measuring probe;

Step 3: Adjust the position of the tooling so that the rotation axis on the telescopic arm is at the center of the semicircular arch scanning frame;

Step 4: The turntable is controlled by the first control system so that the horn antenna rotates in the scanning plane, and the telescopic arm is controlled to rotate to the angular position of the measuring probe on the semicircular arched scanning frame, so that the horn antenna is radially aligned with the probe antenna;

Step 5: Repeat step 4, align the horn antenna with the measuring probe one by one, and collect the data C(θ _n ) of each channel, and finally get C(θ);

Step 6: Change the distance between the horn antenna and the measuring probe, and re-collect data for verification;

用对应的通道数据来校准。Step 7: Measure the data of the hemispherical surface of the antenna under test

Use the corresponding channel data to calibrate.

The method for calibrating the multi-probe spherical near-field channel, wherein, the specific steps of the step 3 are as follows: set the connection line at the center of the measuring probe to form a semicircle whose equation is x ² +y ² =r ² , y≥0 , where the position of the rotation axis in the scanning plane is (x ₀ , y ₀ ); x ₀ , y ₀ and r are controlled by the first turntable and the rotation of the telescopic arm is controlled by the system, so that the horn antenna points to the three measuring probes, The distances L ₁ , L ₂ , and L 3 between the bell mouth surface and the three measuring probes are respectively measured by the laser rangefinder. Formula ₂ :

$\left\{\begin{array}{c}{<span\; class="notranslate">\; [</span>{\mathrm{<span\; class="notranslate">\; x</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; r</span>}\mathrm{<span\; class="notranslate">\; cos</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; \&theta;</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; ]</span>}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; +</span>{<span\; class="notranslate">\; [</span>{\mathrm{<span\; class="notranslate">\; the\; y</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; r</span>}\mathrm{<span\; class="notranslate">\; sin</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; \&theta;</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; ]</span>}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; =</span>{<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; L</span>}\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; L</span>}<span\; class="notranslate">\; )</span>}^{\mathrm{<span\; class="notranslate">\; 2</span>}}\\ {<span\; class="notranslate">\; [</span>{\mathrm{<span\; class="notranslate">\; x</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; r</span>}\mathrm{<span\; class="notranslate">\; cos</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; \&theta;</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; ]</span>}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; +</span>{<span\; class="notranslate">\; [</span>{\mathrm{<span\; class="notranslate">\; the\; y</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; r</span>}\mathrm{<span\; class="notranslate">\; sin</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; \&theta;</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; ]</span>}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; =</span>{<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; L</span>}\mathrm{<span\; class="notranslate">\; 2</span>}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; L</span>}<span\; class="notranslate">\; )</span>}^{\mathrm{<span\; class="notranslate">\; 2</span>}}\\ {<span\; class="notranslate">\; [</span>{\mathrm{<span\; class="notranslate">\; x</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; r</span>}\mathrm{<span\; class="notranslate">\; cos</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; \&theta;</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; ]</span>}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; +</span>{<span\; class="notranslate">\; [</span>{\mathrm{<span\; class="notranslate">\; the\; y</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; r</span>}\mathrm{<span\; class="notranslate">\; sin</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; \&theta;</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; ]</span>}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; =</span>{<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; L</span>}\mathrm{<span\; class="notranslate">\; 3</span>}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; L</span>}<span\; class="notranslate">\; )</span>}^{\mathrm{<span\; class="notranslate">\; 2</span>}}\end{array}\right.$

Among them, L is the distance from the mouth surface of the horn antenna to the axis of rotation, (x ₀ , y ₀ ) can be obtained from the equation, and the deviation between the horn antenna and the center (0, 0) of the semicircular arched scanning frame is calculated, through The first control system controls the turntable until the measured distances L ₁ , L ₂ , and L ₃ from the three measuring probes are equal. At this time, the rotating shaft is placed at the center of the semicircular arched scanning frame, and the laser rangefinder is removed. .

The multi-probe spherical near-field channel calibration method, wherein, the specific steps of the step 4 are: first select and align the measurement probe; the switch matrix of the computer controls the channel corresponding to the measurement probe to turn on the switch, and uses the vector The network analyzer receives the data received by the channel, that is, the data C(θ ₁ ) corresponding to the angle θ ₁ , and then closes the channel.

The multi-probe spherical near-field channel calibration method, wherein, in the step 6, the step of verifying is: the second control system radially adjusts the length of the telescopic arm, so that the horn antenna and each probe The distance is R', and then use the loop step 4 and step 5 to collect the data C'(θ) of each measuring probe channel, compare the amplitude and phase of the C(θ) and C'(θ) data, if the amplitude difference is small, And there is a fixed phase difference between the phases of each corresponding θ, then the method is effective.

将测量探头通道的通道特性的数据记为C(θ)，则用对应的通道数据来校准，公式一： The multi-probe spherical near-field channel calibration method, wherein, in the step 7, the calibration step is: record the measured data of the hemispherical surface of the antenna under test as

Record the channel characteristic data of the measuring probe channel as C(θ), then use the corresponding channel data to calibrate, formula 1:

The multi-probe spherical near-field channel calibration device includes a turntable, a semicircular arched scanning frame, several measuring probes, a switch matrix, a vector network analyzer and a computer acquisition and control system, wherein it also includes a tooling, a rotating shaft, a telescopic arm, Directional antenna, laser rangefinder, first turntable control system, and second turntable control system; the tooling is set on the turntable, the rotating shaft is set on the tooling, and the telescopic arm is set on the rotating shaft , the directional antenna is arranged on the telescopic arm, and a laser range finder is arranged on the directional antenna; the first turntable control system is connected to the tooling for controlling the tooling to move left and right or up and down moving; the second turntable control system is connected to the turntable to control the turntable.

The multi-probe spherical near-field channel calibration device, wherein the directional antenna is a horn antenna and is set at the same distance from the plurality of measuring probes; the laser range finder is fixed on the Oral face of the directional antenna.

Using the above scheme, the directional horn is used to accurately calibrate the near-field measurement data of the antenna spherical multi-probe, which avoids the influence of the backward ground on the performance of the antenna.

Description of drawings

FIG. 1 is a schematic diagram of a multi-probe antenna spherical near-field measurement system in the prior art.

Fig. 2 is a schematic diagram of a multi-probe spherical near-field channel calibration device of the present invention.

Fig. 3 is a flow chart of the multi-probe spherical near-field channel calibration method of the present invention.

Detailed ways

The present invention will be described in detail below in conjunction with the accompanying drawings and specific embodiments.

Example 1

用对应的通道数据来校准，公式一：The invention discloses a multi-probe spherical near-field channel calibration device and method. The principle is that the directional antenna with small backward radiation and little influence from the ground is selected as the calibration antenna, and the horn antenna is specifically selected here. In the multi-probe spherical near-field measurement system as shown in Figure 2, at the same distance from all probe antennas, the calibration antennas are sequentially aligned with the maximum radiation direction along the radial direction of the probe antennas, and the vector network analyzer also records sequentially. The antenna transmits data that is aimed at the probe's channel receive signal. Since the horn antenna is irradiated in the maximum direction every time, the difference in the calibration sky pattern is eliminated, and the difference in the path distance is eliminated by sending and receiving at the same distance, so the collected data only has the characteristics of the channel. This is the data C(θ) of the channel characteristics we want to get. Then the data of the hemispherical surface of the antenna under test measured by the system

Use the corresponding channel data to calibrate, formula 1:

In order to verify the effectiveness of this method, the distance from the calibration antenna to the probe can also be changed, and then the measurement is performed. The data of the two measurements are different from the distance that the electromagnetic wave propagates in space, and other conditions are the same as before, so the channel at this time Compared with the previous data, there is almost no difference in the amplitude, and the two phase differences between each channel are the same value. If so, the method is valid.

In the system shown in Figure 2 equipped with a calibration device, the calibration antenna 4 is used as a transmitting antenna, and the transmitting port of the vector network provides the transmitting signal. The calibration antenna 4 is fixed on the turntable 8 by the telescopic arm 3, the rotating shaft 6 and the tooling 7. The turntable control system 11 can control the tooling 7 to move left and right along the direction a and up and down along the direction b in the scanning plane, and the telescopic arm 3 can be stretched in the radial direction c to adjust the distance from the antenna to the probe. In addition, there is a detachable clamp-fixed laser range finder 5 in the center of the calibration antenna mouth, which is used for aligning the calibration antenna and the probe. Probe antennas 2 are distributed on the semicircular arched scanning frame 1 (the center of each probe has been marked), and the received signal of each probe is received by the vector network analyzer 10 through the matrix switch 9 controlled by the computer 13 . The data of each channel can be obtained.

The specific scheme of calibration using this device is as follows, as shown in Figure 2-Figure 3:

Step 101: Install and connect the system according to Figure 2, and start the system. The horn antenna 4 is a transmitting antenna, the probe is a receiving antenna, and the horn antenna E (or H plane) plane is in the θ plane of spherical coordinates.

Step 102: Adjust the E (or H) plane of the calibration antenna to be within the scanning plane. Fix the fixture with the laser range finder on the horn antenna mouth, turn the turntable 8 by the turntable control system 12, make the E (or H) plane of the antenna into the scanning plane, adjust the telescopic arm 3 to point to a probe, and look at the horn Whether the beams of the laser range finder on the antenna can point to the center of a probe respectively. Otherwise, continue to turn the turntable 8 to adjust until the light velocity of the laser range finder on the horn antenna can point to the center of the probe. At this point, it is ensured that the E (or H) plane of the antenna is within the scanning plane. Adjust the position of the tooling 7 so that the rotating shaft 6 of the telescopic arm 3 is at the center of the circle. Assuming that the connecting line between the probe centers forms a semicircle with the equation x ² +y ² =r ² , y≥0, the position of the rotation axis 6 in the scanning plane is (x ₀ , y ₀ ). The rotation of the telescopic arm is controlled by the turntable control system 11, so that the antenna points to the three probes. In order to point accurately, it is necessary to adjust the rotation of the telescopic arm until the laser beam of the rangefinder points to the center of the probe, and the distance L ₁ , L ₂ , L ₃ . Then a system of equations can be established, formula 2:

$\left\{\begin{array}{c}{<span\; class="notranslate">\; [</span>{\mathrm{<span\; class="notranslate">\; x</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; r</span>}\mathrm{<span\; class="notranslate">\; cos</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; \&theta;</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; ]</span>}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; +</span>{<span\; class="notranslate">\; [</span>{\mathrm{<span\; class="notranslate">\; the\; y</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; r</span>}\mathrm{<span\; class="notranslate">\; sin</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; \&theta;</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; ]</span>}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; =</span>{<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; L</span>}\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; L</span>}<span\; class="notranslate">\; )</span>}^{\mathrm{<span\; class="notranslate">\; 2</span>}}\\ {<span\; class="notranslate">\; [</span>{\mathrm{<span\; class="notranslate">\; x</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; r</span>}\mathrm{<span\; class="notranslate">\; cos</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; \&theta;</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; ]</span>}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; +</span>{<span\; class="notranslate">\; [</span>{\mathrm{<span\; class="notranslate">\; the\; y</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; r</span>}\mathrm{<span\; class="notranslate">\; sin</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; \&theta;</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; ]</span>}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; =</span>{<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; L</span>}\mathrm{<span\; class="notranslate">\; 2</span>}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; L</span>}<span\; class="notranslate">\; )</span>}^{\mathrm{<span\; class="notranslate">\; 2</span>}}\\ {<span\; class="notranslate">\; [</span>{\mathrm{<span\; class="notranslate">\; x</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; r</span>}\mathrm{<span\; class="notranslate">\; cos</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; \&theta;</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; ]</span>}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; +</span>{<span\; class="notranslate">\; [</span>{\mathrm{<span\; class="notranslate">\; the\; y</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; r</span>}\mathrm{<span\; class="notranslate">\; sin</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; \&theta;</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; ]</span>}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; =</span>{<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; L</span>}\mathrm{<span\; class="notranslate">\; 3</span>}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; L</span>}<span\; class="notranslate">\; )</span>}^{\mathrm{<span\; class="notranslate">\; 2</span>}}\end{array}\right.$

Where L is the distance from the antenna aperture to the rotating shaft 6 . (x ₀ , y ₀ ) can be obtained from the equation, and its deviation from the center of the circle (0, 0) is known. Through the turntable control system 11, the adjustment 8 moves along the a and b directions respectively until the measured L ₁ , When L ₂ and L ₃ are equal, the rotating shaft 6 is placed at the center of the circle, and the laser rangefinder is removed.

Step 103: Collect channel data. The turntable control system 11 controls the rotation of the antenna in the scanning plane, and controls the telescopic arm to rotate to the angular position of the probe on the circle, so that the radial alignment of the probe antenna can be ensured. First select Alignment Probe ①. The computer 13 controls the switch matrix to turn on the switch of the channel corresponding to the probe ① to make it conduct, and use the vector network analyzer to receive the data received by the ① channel, that is, the data C(θ ₁ ) corresponding to the angle θ ₁ , and then close the ① channel. According to the above step 4), align the calibration antenna with the remaining probes one by one, collect the data C(θ _n ) of each channel, and finally get C(θ).

Step 104: Change the distance between the calibration antenna and the probe, and re-collect data for verification. Adjust the length of the telescopic arm 3 by a small distance along the radial direction b by the turntable control system, so that the distance between the calibration antenna and each probe is R', and then use steps 4) and 5) to collect data C'( θ).

Step 105: Compare the amplitude and phase of C(θ) and C'(θ) data, if the amplitude difference is small, there is a fixed phase difference between the phases of each corresponding θ, which can verify that this method is accurate and effective.

Step 106 and Step 107: Measure the data of the hemispherical surface of the antenna under test Use the corresponding channel data to calibrate.

By adopting the above-mentioned device and method, the rear direction of the directional antenna will not have strong radiation, and the reflection of the ground will not have a great impact on the pattern. Accurate tooling ensures that the rotation center of the antenna is at the center of the scanning frame, so that the path distance from the phase center of the calibration antenna to each channel is consistent; the precise pointing ensures that the antenna is aligned with the maximum beam pointing (same direction) every time to avoid calibration The influence of the antenna itself on the calibration process.

It should be understood that those skilled in the art can make improvements or changes based on the above description, and all these improvements and changes should belong to the protection scope of the appended claims of the present invention.

Claims (7)

1. A multi-probe spherical near-field channel calibration method is characterized in that, comprising the following steps: Step 1: set the horn antenna as the transmitting antenna, and several measuring probes as the receiving antenna, and set the E plane or H plane of the horn antenna to be located in the θ plane of the spherical coordinates; Step 2: Fix the fixture with the laser range finder on the surface of the horn antenna, control the turntable by the second turntable control system, make the E or H plane of the horn antenna into the scanning plane, and adjust the telescopic arm to point to a measurement Probe, set the beam of the laser rangefinder on the horn antenna to point to the center of a measuring probe; Step 3: Adjust the position of the tooling so that the rotation axis on the telescopic arm is at the center of the semicircular arch scanning frame; Step 4: The turntable is controlled by the first control system so that the horn antenna rotates in the scanning plane, and the telescopic arm is controlled to rotate to the angular position of the measuring probe on the semicircular arched scanning frame, so that the horn antenna is radially aligned with the probe antenna; Step 5: Repeat step 4, align the horn antenna with the measuring probe one by one, and collect the data C(θ _n ) of each channel, and finally get C(θ); Step 6: Change the distance between the horn antenna and the measuring probe, and re-collect data for verification; Step 7: Measure the data of the hemispherical surface of the antenna under test

Use the corresponding channel data to calibrate. 2. The multi-probe spherical near-field channel calibration method according to claim 1, characterized in that, the specific steps of said step 3 are: the connection line at the center of the measuring probes is formed by x ² +y ² =r ² , y≥0 is the semicircle of the equation, where the position of the rotation axis in the scanning plane is (x ₀ , y ₀ ); the first turntable controls x ₀ , y ₀ and r and the rotation of the telescopic arm, so that the horn The antenna points to the 3 measuring probes, and the distances L ₁ , L ₂ , and L ₃ between the bell mouth surface and the 3 measuring probes are measured by the laser range finder, formula 2: $\left\{\begin{array}{c}{<span\; class="notranslate">\; [</span>{\mathrm{<span\; class="notranslate">\; x</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; r</span>}\mathrm{<span\; class="notranslate">\; cos</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; \&theta;</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; ]</span>}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; +</span>{<span\; class="notranslate">\; [</span>{\mathrm{<span\; class="notranslate">\; the\; y</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; r</span>}\mathrm{<span\; class="notranslate">\; sin</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; \&theta;</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; ]</span>}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; =</span>{<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; L</span>}\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; L</span>}<span\; class="notranslate">\; )</span>}^{\mathrm{<span\; class="notranslate">\; 2</span>}}\\ {<span\; class="notranslate">\; [</span>{\mathrm{<span\; class="notranslate">\; x</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; r</span>}\mathrm{<span\; class="notranslate">\; cos</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; \&theta;</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; ]</span>}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; +</span>{<span\; class="notranslate">\; [</span>{\mathrm{<span\; class="notranslate">\; the\; y</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; r</span>}\mathrm{<span\; class="notranslate">\; sin</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; \&theta;</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; ]</span>}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; =</span>{<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; L</span>}\mathrm{<span\; class="notranslate">\; 2</span>}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; L</span>}<span\; class="notranslate">\; )</span>}^{\mathrm{<span\; class="notranslate">\; 2</span>}}\\ {<span\; class="notranslate">\; [</span>{\mathrm{<span\; class="notranslate">\; x</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; r</span>}\mathrm{<span\; class="notranslate">\; cos</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; \&theta;</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; ]</span>}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; +</span>{<span\; class="notranslate">\; [</span>{\mathrm{<span\; class="notranslate">\; the\; y</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; r</span>}\mathrm{<span\; class="notranslate">\; sin</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; \&theta;</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; ]</span>}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; =</span>{<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; L</span>}\mathrm{<span\; class="notranslate">\; 3</span>}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; L</span>}<span\; class="notranslate">\; )</span>}^{\mathrm{<span\; class="notranslate">\; 2</span>}}\end{array}\right.$ Among them, L is the distance from the mouth surface of the horn antenna to the axis of rotation, (x ₀ , y ₀ ) can be obtained from the equation, and the deviation between the horn antenna and the center (0, 0) of the semicircular arched scanning frame is calculated, through The first control system controls the turntable until the measured distances L ₁ , L ₂ , and L ₃ from the three measuring probes are equal. At this time, the rotating shaft is placed at the center of the semicircular arched scanning frame, and the laser rangefinder is removed. . 3. multi-probe spherical near-field channel calibration method as claimed in claim 2, is characterized in that, the specific steps of described step 4 are: at first select and align measuring probe; Open the channel corresponding to measuring probe by computer control switch matrix The switch is turned on, the data received by the channel is received by a vector network analyzer, that is, the data C(θ ₁ ) corresponding to the angle θ ₁ , and then the channel is closed. 4. The multi-probe spherical near-field channel calibration method according to claim 3, characterized in that, in the step 6, the step of verifying is: adjusting the length of the telescopic arm radially by the second control system, Make the distance between the horn antenna and each probe R', and then use the loop step 4 and step 5 to collect the data C'(θ) of each measurement probe channel, and compare the amplitude sum of the C(θ) and C'(θ) data phase, this method works if the amplitude difference is small and there is a fixed phase difference between the phases of each corresponding θ. 5. multi-probe spherical near-field channel calibration method as claimed in claim 4, is characterized in that, in described step 7, the step of described calibration is: the data of the hemispherical surface of the measured antenna being measured is denoted as Record the channel characteristic data of the measuring probe channel as C(θ), then use the corresponding channel data to calibrate, formula 1:

6. The multi-probe spherical near-field channel calibration device as described in any one of claims 1-3, comprising a turntable, a semicircular arch scanning frame, some measuring probes, a switch matrix, a vector network analyzer and a computer acquisition and control system, wherein It is characterized in that it also includes a tooling, a rotating shaft, a telescopic arm, a directional antenna, a laser range finder, a first turntable control system, and a second turntable control system; the tooling is set on the turntable, and the rotating shaft is set on the tooling above, the telescopic arm is set on the rotating shaft, the directional antenna is set on the telescopic arm, and a laser range finder is set on the directional antenna; the first turntable control system is set corresponding to the tooling connected to control the tooling to move left and right or up and down; the second turntable control system is connected to the turntable to control the turntable. 7. The multi-probe spherical near-field channel calibration device as claimed in claim 6, wherein the directional antenna is a horn antenna and is set to be the same distance as the plurality of measuring probes; the laser rangefinder passes through a The disassembled clamp is fixed on the mouth surface of the directional antenna.

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