An automatic antenna measurement system based on spherical near-field measurement

Abstract

The invention relates to the field of wireless communication, and discloses an antenna automatic measurement system based on spherical near-field measurement. The technical scheme thereof mainly comprises an antenna automatic measurement system based on spherical near-field measurement, comprising a ring frame, a plurality of probe elements, a reference antenna, an antenna to be tested, a probe selection module, a driving mechanism, a signal transceiver module, a control module and a conversion module. A plurality of probe elements are used to perform spherical near-field testing, and a plurality of probes form a plurality of test channels. In order to reduce the influence of different amplitude and phase characteristics of each channel, mechanical calibration and point calibration are performed respectively, and then the acquired spherical near-field data are converted into far-field data, thereby improving the accuracy of the measurement system and reducing the influence of external factors such as the environment. In addition, data analysis can be performed inside the software, 2D or 3D graphs of test data can be viewed, and test reports in various formats can be generated.

Description

Technical Field

[0001] The present invention relates to the field of wireless communication, and more particularly to an antenna automatic measurement system based on spherical near-field measurement. Background Art

[0002] With the continuous advancement of measurement equipment and computer technology, the electrical performance indicators of antennas can be measured more conveniently and accurately through near-field in a microwave darkroom. However, the spherical near-field has a very small truncation error, and the implementation of probe compensation can also be used for measurement, which can obtain comprehensive antenna measurement radiation characteristic parameters. In addition, the spherical near-field measurement technology can be applied to a variety of antennas such as omnidirectional antennas. With the help of the system, the influence of external factors such as the environment can be reduced, and it is widely used in the field of mobile communication antenna testing. Spherical near-field measurement is one of the near-field measurement methods. The near-field information of the antenna is collected on the virtual sphere surrounding the antenna at a distance of several wavelengths from the antenna to be tested. The complete directional pattern information of the antenna can be calculated through the near-far field transformation. It is an ideal method to obtain the omnidirectional pattern of the antenna to be tested. However, the existing spherical near-field test system has low accuracy of the measurement system due to the influence of different amplitude and phase characteristics between the probes. Summary of the invention

[0003] In view of the deficiencies in the prior art, an object of the present invention is to provide an antenna automatic measurement system based on spherical near-field measurement, which has the characteristics of high measurement accuracy.

[0004] To achieve the above object, the present invention provides the following technical solutions:

[0005] An antenna automatic measurement system based on spherical near-field measurement, comprising:

[0006] Ring rack,

[0007] A plurality of probe elements, each of which comprises two polarization channels, are mounted on the annular frame at the same preset interval angle, a spherical center reference point is defined, and the distance from the spherical center reference point to each of the probe elements meets a preset error condition,

[0008] A reference antenna, wherein the phase center of the reference antenna is set at the spherical center reference point, and the reference antenna receives the calibration electrical signal and radiates electromagnetic waves outwardly,

[0009] The antenna to be tested has its phase center set on the spherical center reference point, and the antenna to be tested receives a test electrical signal and radiates electromagnetic waves outwardly.

[0010] a probe selection module, wherein the probe selection module controls the polarization channels of the probe elements to sequentially receive electromagnetic waves and generate electromagnetic signals,

[0011] A driving mechanism, wherein the antenna to be tested and the reference antenna are driven to rotate by the driving mechanism,

[0012] a signal transceiver module, the signal transceiver module is electrically connected to the probe to be tested and each probe element respectively, the signal transceiver module sends the calibration electrical signal to the reference antenna, and generates calibration data according to the electromagnetic waves received by each probe element, the signal transceiver module sends the electrical test signal to the antenna to be tested, and generates actual test data according to the electromagnetic waves received by each probe element,

[0013] A control module, wherein the control module is electrically connected to the driving mechanism and the signal transceiver module respectively, and the control module performs spherical measurement according to a preset measurement strategy to obtain the actual test data, and performs correction through the calibration data to obtain near-field test data,

[0014] A conversion module is used to input the near-field actual data into a preset conversion model to obtain far-field test data.

[0015] An automatic antenna measurement method based on spherical near-field measurement, providing an automatic antenna measurement system based on spherical near-field measurement as claimed in claim 3, comprising:

[0016] Step S1: Perform mechanical calibration, install the rangefinder on the driving mechanism, use the driving mechanism to drive the rangefinder to rotate to obtain the measured length, the measured length reflects the distance between the rangefinder and each of the probe elements, and adjust the installation position of the probe element until the measured length meets the error condition;

[0017] Step S2: installing the laser positioning member and the reference antenna on the driving mechanism, the driving mechanism intermittently drives the laser positioning member to rotate at a preset interval angle, the control module controls the driving mechanism to rotate until the positioning laser is directly opposite to the probe element, and generates the offset angle to be recorded in the angle offset database, the offset angle reflects the vector angle rotated by the rotating driving member;

[0018] Step S3: Calibration is started according to the preset input test frequency band, intermediate frequency bandwidth, number of scanning points, and transmission power. The control module retrieves the angle offset database and drives the driving mechanism so that the reference antenna faces each probe antenna. The signal transceiver module sends a calibration electrical signal to the reference antenna, and generates calibration data according to the electromagnetic waves received by each probe element.

[0019] Step S4: The antenna to be tested is mounted on the driving mechanism, and the control module performs spherical measurement according to a preset measurement strategy to obtain the actual test data, and performs correction through the calibration data to obtain near-field test data;

[0020] Step S5: The conversion module inputs the near-field actual data into a preset conversion model to obtain far-field test data, and outputs the far-field test data after being processed by the analysis module.

[0021] In the present invention, preferably, the antenna automatic measurement system includes a positioning mechanism, the positioning mechanism includes a rangefinder, the rangefinder is installed on the rotating drive member and electrically connected to the control module, the rangefinder measures the distance between each of the probe elements to be defined as a measuring length, the error condition is specifically that the difference between any two of the measuring lengths is less than a preset length error value, and the installation position of each of the probe elements is adjusted to meet the error condition.

[0022] In the present invention, preferably, the control module is preset with an angle offset database.

[0023] The positioning mechanism includes a laser positioning member, which is mounted on the rotating drive member and can generate a positioning laser. The rotating drive member sequentially drives the laser positioning member to rotate at the preset interval angle. If an offset occurs between the positioning laser and the probe element, the rotation angle of the driving mechanism is adjusted until the positioning laser and the probe element are directly opposite, and the offset angle is generated to be recorded in the angle offset database. The offset angle reflects the vector angle rotated by the rotating drive member.

[0024] The control module calls the angle offset database and controls the driving mechanism to deflect the vector angle so that the reference antenna faces each of the probe elements in sequence, thereby acquiring the calibration data.

[0025] In the present invention, preferably, the driving mechanism is configured as a turntable, the turntable comprises a first rotating shaft and a second rotating shaft perpendicular to each other, and the first rotating shaft is parallel to the side surface of the annular frame.

[0026] In the present invention, preferably, the calibration data includes S parameters and the amplitude and phase of horizontal polarization, and the amplitude and phase of vertical polarization of each probe element.

[0027] In the present invention, preferably, the far-field data includes gain, bandwidth, left-hand polarization value, right-hand polarization value, front-to-back ratio, and axial ratio.

[0028] In the present invention, preferably, it also includes an analysis module, which obtains the far-field test data for data analysis and processing, and can output it in the form of charts, including rectangular coordinate charts, polar coordinate charts, list charts and 3D spherical charts.

[0029] In the present invention, preferably, a signal amplification module is further included, wherein the signal amplification module is connected to the probe selection module and the signal transceiver module, and the signal amplification module is used to amplify the electromagnetic signal generated by the probe element to send it to the signal transceiver module.

[0030] In the present invention, preferably, the signal transceiver module performs self-calibration in advance before step S1.

[0031] Beneficial effects of the present invention:

[0032] 1. The present invention uses spherical near-field test, near-field to far-field conversion, and data analysis as independent modules, and can select the required modules according to the needs in one system, which is convenient to use. In addition, the near-field to far-field conversion is performed internally, and the converted test data can be directly viewed;

[0033] 2. Use multiple probe elements for measurement, and use mechanical calibration to correct the installation errors of each probe element. Use electrical calibration to calibrate the loss data of each probe element, and make the reference antenna face the probe antenna every time, thereby eliminating the influence of the reference antenna radiation pattern characteristics. The difference in path distances when receiving and transmitting signals at the same distance is eliminated, thereby improving the accuracy of detection. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 is a schematic diagram of the system architecture of the antenna automatic measurement system in the embodiment;

[0035] Figure 2 1 is a flowchart of the steps of the antenna automatic measurement method in the embodiment.

[0036] Reference numerals:

[0037] 1. Ring frame; 11. Probe element; 2. Probe selection module; 3. Driving mechanism; 31. Reference antenna; 32. Antenna to be tested; 4. Signal transceiver module; 5. Control module; 6. Conversion module; 7. Positioning mechanism; 8. Analysis module; 9. Signal amplification module. DETAILED DESCRIPTION

[0038] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only 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.

[0039] It should be noted that when a component is referred to as being "fixed to" another component, it may be directly on the other component or there may also be a component centered. When a component is considered to be "connected to" another component, it may be directly connected to the other component or there may also be a component centered. When a component is considered to be "set on" another component, it may be directly set on the other component or there may also be a component centered. The terms "vertical", "horizontal", "left", "right" and similar expressions used herein are for illustrative purposes only.

[0040] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art of the present invention. The terms used herein in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "and / or" used herein includes any and all combinations of one or more related listed items.

[0041] Please also see Figure 1 to Figure 2 The present embodiment provides an antenna automatic measurement system based on spherical near-field measurement, including a ring frame 1, a plurality of probe elements 11, a reference antenna 31, an antenna to be measured 32, a probe selection module 2, a driving mechanism 3, a signal transceiver module 4, a control module 5, and a conversion module 6.

[0042] In this embodiment, the number of probe elements 11 is set to 64, each probe element 11 includes two polarization channels, and the number of polarization channels is 128 in total. Each probe element 11 is installed on the ring frame 1 at the same preset interval angle. In this embodiment, the preset interval angle is set to 5.29°. It is defined that there is a spherical center reference point, and the distance from the spherical center reference point to each probe element 11 meets the preset error condition. The phase center of the reference antenna 31 is set at the spherical center reference point. The reference antenna 31 receives the calibration electrical signal and radiates electromagnetic waves outward, and is specifically set as a standard gain antenna. The phase center of the antenna to be tested 32 is set at the spherical center reference point. The antenna to be tested 32 receives the test electrical signal and radiates electromagnetic waves outward. The probe selection module 2 controls the polarization channels of each probe element 11 to receive electromagnetic waves and generate electromagnetic signals in turn. The probe selection module 2 is specifically an antenna probe control box, which is used to control the probe switch and polarization switching. The antenna to be tested 32 and the reference antenna 31 are driven to rotate by the driving mechanism 3.

[0043] The signal transceiver module 4 is electrically connected to the probe to be tested and each probe element 11 respectively. The signal transceiver module 4 sends a calibration electrical signal to the reference antenna 31, and generates calibration data according to the electromagnetic waves received by each probe element 11. The signal transceiver module 4 sends an electrical test signal to the antenna to be tested 32, and generates actual test data according to the electromagnetic waves received by each probe element 11. The signal transceiver module 4 is specifically a vector network analyzer. The vector network analyzer is a signal transceiver device, which is connected to the control module 5. It generates a pulsed radio frequency signal of specified parameters under the control of the main control computer, and transmits it through the antenna to be tested 32 or the reference antenna 31, which is received by the probe element 11 and transmitted to the receiving port of the vector network analyzer. The instrument supports instruments from many mainstream instrument companies such as R&S, Keysight, and Galaxy Bright Point.

[0044] The control module 5 is electrically connected to the driving mechanism 3 and the signal transceiver module 4 respectively. The control module 5 performs spherical measurement according to a preset measurement strategy to obtain actual test data, and performs correction through calibration data to obtain near-field test data. The conversion module 6 inputs the actual near-field data into a preset conversion model to obtain far-field test data. The control module 5 is preset with an angle offset database.

[0045] The antenna automatic measurement system includes a positioning mechanism 7, which includes a rangefinder and a laser locator. The rangefinder is specifically a laser rangefinder, which is installed on the rotating drive member and electrically connected to the control module 5. The rangefinder measures the distance between each probe element 11 to define the measurement length. The error condition is specifically that the difference between any two measured lengths is less than the preset length error value, and the installation position of each probe element 11 is adjusted to meet the error condition. This operation is specifically a mechanical calibration operation. Since there is an installation error in the installation of the probe element 11, the installation accuracy is improved by mechanical calibration.

[0046] The laser positioning member of the positioning mechanism 7 is installed on the rotating drive member and can generate a cross positioning laser. The rotating drive member drives the laser positioning member to rotate in sequence at a preset interval angle. If there is an offset between the positioning laser and the probe element 11, the rotation angle of the driving mechanism 3 is adjusted to the positioning laser and the probe element 11, and the offset angle is generated to be recorded in the angle offset database. The offset angle reflects the vector angle of the rotating driving member. The control module 5 calls the angle offset database and controls the deflection vector angle of the driving mechanism 3 to make the reference antenna 31 face each probe element 11 in sequence, thereby obtaining calibration data. This operation is specifically electrical calibration. The calibration data is mainly the signal loss of the entire spherical near-field environment, the signal emitted from the reference antenna 31 passes through the probe selection module 2, controls the probe switch and polarization switching, and reaches the probe antenna. The corresponding antenna probe loss data is obtained by collecting the trace data of the vector network analyzer and using the algorithm to calculate. The loss calibration only needs to be calibrated once at the beginning. The calibration data includes S parameters and the amplitude and phase of the horizontal polarization of each probe element 11, and the amplitude and phase of the vertical polarization, which can further improve the test accuracy. Far-field data include gain, bandwidth, left-hand polarization value, right-hand polarization value, front-to-back ratio, and axial ratio.

[0047] The driving mechanism 3 is configured as a turntable, which includes a first rotation axis and a second rotation axis perpendicular to each other, and the first rotation axis is parallel to the side of the ring frame 1. In this embodiment, the first rotation axis is specifically configured perpendicular to the horizontal plane, and the second rotation axis is specifically configured parallel to the horizontal plane, i.e., the pitch rotation axis.

[0048] The antenna automatic measurement system also includes an analysis module 8 and a signal amplification module 9. The analysis module 8 obtains far-field test data for data analysis and processing, and can output it in the form of charts, including rectangular coordinate charts, polar coordinate charts, list charts and 3D spherical charts. The signal amplification module 9 is connected to the probe selection module 2 and the signal transceiver module 4. The signal amplification module 9 is used to amplify the electromagnetic signal generated by the probe element 11 to send it to the signal transceiver module 4. The control module 5 inputs different instructions to the amplification module according to different test frequency bands, so as to achieve the purpose of amplifying different signals in different frequency bands.

[0049] The present invention uses a host computer as the control and test core of the test system. The user operates the host computer software of the test system to issue control protocol instructions, control corresponding instruments and equipment, and collect antenna probe amplitude data. The present invention can run stably and collect data quickly without manually setting parameters on the instrument and manually collecting antenna probe calibration data. The test is convenient to use, the test efficiency is improved, and most of the time is saved.

[0050] An antenna automatic measurement method based on spherical near-field measurement, comprising:

[0051] Step S1: Perform mechanical calibration, install the rangefinder on the driving mechanism 3, use the driving mechanism 3 to drive the rangefinder to rotate to obtain the measured length, the measured length reflects the distance between the rangefinder and each probe element 11, and adjust the installation position of the probe element 11 until the measured length meets the error condition;

[0052] Step S2: The laser positioning member and the reference antenna 31 are mounted on the driving mechanism 3. The driving mechanism 3 drives the laser positioning member to rotate intermittently at a preset interval angle. The control module 5 controls the driving mechanism 3 to rotate until the positioning laser is directly facing the probe element 11, and generates an offset angle to be recorded in the angle offset database. The offset angle reflects the vector angle of the rotating driving member.

[0053] Step S3: Calibration is started according to the preset input test frequency band, intermediate frequency bandwidth, number of scanning points, and transmission power. The control module 5 retrieves the angle offset database and drives the driving mechanism 3 so that the reference antenna 31 faces each probe antenna. The signal transceiver module 4 sends a calibration electrical signal to the reference antenna 31 and generates calibration data according to the electromagnetic waves received by each probe element 11.

[0054] Step S4: The antenna 32 to be tested is mounted on the driving mechanism 3, and the control module 5 performs spherical measurement according to a preset measurement strategy to obtain actual test data, and performs correction through calibration data to obtain near-field test data;

[0055] Step S5: the conversion module 6 inputs the near-field actual data into a preset conversion model to obtain far-field test data, and outputs the data after being processed by the analysis module 8. The conversion model specifically adopts an existing conversion model, which will not be described in detail in this application.

[0056] The signal transceiver module 4 performs self-calibration in advance before step S1.

[0057] In step S4, first the driving mechanism 3 returns to the initial position and starts to collect data at the initial position. The control module 5 sends relevant instructions to turn on the signal amplifier, and the Port1 port of the vector network analyzer starts to transmit power. At this time, the antenna probe control box switches the antenna probe and polarization at a speed of 1ms. After the antenna probe control box completes the switching of 64 antennas and polarizations (128 channels), the data will be returned through the Port2 port of the vector network analyzer, and the actual test data will be corrected using the calibration data (the correction process is: actual test data-calibration data). At this time, the control module 5 records the near-field test data, and the positioner starts to move to the next position according to the set step, and collects data in sequence according to the specified flow. During the data collection process, the PC software will display the test trace, real-time data and log, which is convenient for observing the correctness of the collected data during the data collection process. If a test error occurs, stop in time to troubleshoot the problem, and restart the test after the detection is completed.

[0058] The above are only preferred embodiments of the present invention. The protection scope of the present invention is not limited to the above embodiments. All technical solutions under the concept of the present invention belong to the protection scope of the present invention. It should be pointed out that for ordinary technicians in this technical field, some improvements and modifications without departing from the principle of the present invention should also be regarded as the protection scope of the present invention.

Claims

1. An antenna automatic measurement system based on spherical near-field measurement, characterized in that: include Ring frame (1), A plurality of probe elements (11), each of the probe elements (11) comprising two polarization channels, each of the probe elements (11) being mounted on the annular frame (1) at the same preset interval angle, a spherical center reference point being defined, and a distance from the spherical center reference point to each of the probe elements (11) meeting a preset error condition, A reference antenna (31), wherein the phase center of the reference antenna (31) is arranged at the spherical center reference point, and the reference antenna (31) receives a calibration electrical signal and radiates electromagnetic waves outwardly. An antenna to be tested (32), wherein the phase center of the antenna to be tested (32) is arranged on the spherical center reference point, and the antenna to be tested (32) receives a test electrical signal and radiates electromagnetic waves outwardly, A probe selection module (2), wherein the probe selection module (2) controls the polarization channels of the probe elements (11) to sequentially receive electromagnetic waves and generate electromagnetic signals. A driving mechanism (3), wherein the antenna to be tested (32) and the reference antenna (31) are driven to rotate by the driving mechanism (3). A signal transceiver module (4), the signal transceiver module (4) being electrically connected to the antenna to be tested (32) and each probe element (11) respectively, the signal transceiver module (4) sending the calibration electrical signal to the reference antenna (31), and generating calibration data according to the electromagnetic waves received by each probe element (11), the signal transceiver module (4) sending the electrical test signal to the antenna to be tested (32), and generating actual test data according to the electromagnetic waves received by each probe element (11), A control module (5), the control module (5) being electrically connected to the drive mechanism (3) and the signal transceiver module (4) respectively, the control module (5) performing spherical measurement according to a preset measurement strategy to obtain the actual test data, and performing correction through the calibration data to obtain near-field test data, A conversion module (6), wherein the conversion module (6) inputs the near-field test data into a preset conversion model to obtain far-field test data; The antenna automatic measurement system comprises a positioning mechanism (7), the positioning mechanism (7) comprises a rangefinder, the rangefinder is mounted on the rotating drive member and is electrically connected to the control module (5), the rangefinder measures the distance between each of the probe elements (11) to define the measured length, the error condition is specifically that the difference between any two of the measured lengths is less than a preset length error value, and the installation position of each of the probe elements (11) is adjusted to meet the error condition; The control module (5) is preset with an angle offset database, The positioning mechanism (7) comprises a laser positioning member, which is mounted on the rotating drive member and is capable of generating a positioning laser. The rotating drive member sequentially drives the laser positioning member to rotate at the preset interval angle. If an offset occurs between the positioning laser and the probe element (11), the rotation angle of the driving mechanism (3) is adjusted until the positioning laser and the probe element (11) are aligned, and an offset angle is generated to be recorded in the angle offset database, wherein the offset angle reflects the vector angle of the rotating drive member. The control module (5) calls the angle offset database and controls the driving mechanism (3) to deflect the vector angle so that the reference antenna (31) faces each of the probe elements (11) in sequence, thereby acquiring the calibration data.

2. The antenna automatic measurement system based on spherical near-field measurement according to claim 1, characterized in that: The driving mechanism (3) is configured as a turntable, the turntable comprising a first rotating shaft and a second rotating shaft which are perpendicular to each other, the first rotating shaft being parallel to the side surface of the annular frame (1).

3. The antenna automatic measurement system based on spherical near-field measurement according to claim 1, characterized in that: The calibration data includes S parameters and the amplitude and phase of horizontal polarization and the amplitude and phase of vertical polarization of each probe element (11).

4. The antenna automatic measurement system based on spherical near-field measurement according to claim 1, characterized in that: The far-field test data includes gain, bandwidth, left-hand polarization value, right-hand polarization value, front-to-back ratio, and axial ratio.

5. The antenna automatic measurement system based on spherical near-field measurement according to claim 1, characterized in that: It also includes an analysis module (8), which acquires the far-field test data for data analysis and processing, and can output the data in the form of graphs, including rectangular coordinate graphs, polar coordinate graphs, list graphs, and 3D spherical graphs.

6. The antenna automatic measurement system based on spherical near-field measurement according to claim 1, characterized in that: It also includes a signal amplification module (9), which is connected to the probe selection module (5) (2) and the signal transceiver module (4), and the signal amplification module (9) is used to amplify the electromagnetic signal generated by the probe element (11) to send it to the signal transceiver module (4).

7. An automatic antenna measurement method based on spherical near-field measurement, providing an automatic antenna measurement system based on spherical near-field measurement as claimed in claim 1, characterized in that: include Step S1: Perform mechanical calibration, install the distance meter on the driving mechanism (3), use the driving mechanism (3) to drive the distance meter to rotate to obtain the measured length, the measured length reflects the distance between the distance meter and each of the probe elements (11), and adjust the installation position of the probe element (11) until the measured length meets the preset error condition; Step S2: installing the laser positioning member and the reference antenna (31) on the driving mechanism (3), the driving mechanism (3) intermittently driving the laser positioning member to rotate at a preset interval angle, the control module (5) controlling the driving mechanism (3) to rotate until the positioning laser is directly opposite to the probe element (11), and generating the offset angle to be recorded in the angle offset database, wherein the offset angle reflects the vector angle rotated by the rotating driving member; Step S3: Calibration is started according to the preset input test frequency band, intermediate frequency bandwidth, number of scanning points, and transmission power. The control module (5) retrieves the angle offset database and drives the driving mechanism (3) so that the reference antenna (31) faces each probe antenna. The signal transceiver module (4) sends a calibration electrical signal to the reference antenna (31), and generates calibration data according to the electromagnetic waves received by each probe element (11). Step S4: the antenna to be tested (32) is mounted on the driving mechanism (3), and the control module (5) performs spherical measurement according to a preset measurement strategy to obtain the actual test data, and performs correction using the calibration data to obtain near-field test data; Step S5: the conversion module (6) inputs the near-field test data into a preset conversion model to obtain far-field test data, and outputs the far-field test data after being processed by the analysis module (8).

8. The method for automatic antenna measurement based on spherical near-field measurement according to claim 7, characterized in that: The signal transceiver module (4) performs self-calibration in advance before step S1.

Images