A single-polarization spherical near-field sampling method

Abstract

The present invention discloses a single-polarization spherical near-field sampling method, wherein a symmetrically distributed horizontal polarization probe and a vertical polarization probe are set at the near-zone spherical position of the antenna under test, so that the antenna under test rotates. The horizontal polarization probe and the vertical polarization probe respectively obtain horizontal sampling signal data and vertical sampling signal data of the antenna under test, interpolate the horizontal sampling signal data and the vertical sampling signal data, and synthesize the cross-polarization components of each sampling position to obtain the near-field data of the antenna under test. The present invention provides a single-polarization spherical near-field sampling method, which uses a single-polarization detection probe to obtain two components of the antenna under test, interpolate the obtained near-field data, and synthesize the near-field data. The dual-channel probe calibration is changed to a single-channel calibration, thereby reducing the difficulty of consistency calibration, eliminating the need for additional signal separation calculations in actual applications, reducing the difficulty and complexity of testing, and improving the accuracy of near-field data.

Description

Technical Field

[0001] The present invention relates to the technical field of antenna testing, and more particularly to a single-polarization spherical near-field sampling method. Background Art

[0002] Antenna measurement technologies include far-field measurement, compressed field measurement, and near-field measurement. Existing far-field measurement can measure three-dimensional patterns, but requires a large test distance and is susceptible to external interference. It also has high construction costs and low test efficiency. Near-field measurement, on the other hand, requires a smaller test distance, offers an easily controllable test environment, and has low construction costs and high test efficiency. Therefore, far-field data is often obtained by converting near-field data: the antenna under test is typically placed in a darkroom, and a detection probe is used to scan a spherical surface close to the antenna to obtain its near-field data. The far-field data of the antenna under test is then converted using a near-to-far-field conversion algorithm, yielding the far-field pattern.

[0003] In the aforementioned far-field data acquisition process, the detection probe used to obtain near-field data is a dual-channel cross-polarization probe. For example, as described in patent documents 201610614730.X (A Near-Field Antenna Measurement Method for Arbitrary Surface Scanning) and 202110299350.2 (A Near-Field Antenna Measurement Method and Apparatus Using an Interpolation Algorithm), both of these patent documents employ multi-channel cross-polarization probes for near-field data measurement. These cross-polarization probes are used to obtain the radio wave signal components required for the near-field to far-field conversion algorithm, facilitating the near-field to far-field conversion calculation. However, when using such cross-polarization probes to obtain near-field data, the two channels of the dual-channel cross-polarization probes must be calibrated for consistency before testing, which increases the difficulty and complexity of testing. Furthermore, the two channels of the cross-polarization probes interact with each other, necessitating the use of additional algorithms to separate the signals during the actual calibration process. This consistency calibration and signal separation increase the difficulty and complexity of testing, while also impacting the accuracy of the near-field data and reducing the accuracy of the far-field data obtained by the test system. Summary of the Invention

[0004] In order to overcome the shortcomings of the prior art that the use of a dual-channel cross-polarization probe leads to increased testing difficulty, increased testing complexity, and reduced near-field data accuracy, the present invention provides a single-polarization spherical near-field sampling method, which uses a single-polarization detection probe to respectively obtain two components of the antenna under test, interpolate the obtained near-field data, and synthesize the near-field data, i.e., the cross-polarization component, and change the dual-channel probe calibration to a single-channel calibration, thereby reducing the difficulty of consistency calibration, and there is no need to consider the influence between the two channels. There is no need to perform additional signal separation calculations in actual applications, which reduces the difficulty and complexity of testing, improves the accuracy of near-field data, and makes it easier to obtain accurate far-field data of the antenna under test.

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

[0006] A single-polarization spherical near-field sampling method is disclosed. In this method, symmetrically distributed horizontal polarization probes and vertical polarization probes are set at the near-zone spherical position of the antenna under test, so that the antenna under test rotates. The horizontal polarization probes and the vertical polarization probes respectively obtain horizontal sampling signal data and vertical sampling signal data of the antenna under test. The horizontal sampling signal data and the vertical sampling signal data are interpolated and then synthesized to obtain cross-polarization components at each sampling position to obtain near-field data of the antenna under test.

[0007] In the above-mentioned single-polarization spherical near-field sampling method, the antenna under test is placed at the test center of the antenna test system, the horizontal polarization probe and the vertical polarization probe are both arranged on the sampling ring of the antenna test system, and the test center coincides with the center position of the sampling ring.

[0008] Furthermore, the horizontal polarization probe and the vertical polarization probe are respectively arranged on both sides of the sampling ring, the setting position of the horizontal polarization probe is symmetrical to the setting position of the vertical polarization probe, and the spacing distance between two adjacent horizontal polarization probes is equal to the spacing distance between two adjacent vertical polarization probes.

[0009] Furthermore, the horizontal polarization probe and the vertical polarization probe are both arranged on one side of the sampling ring, the horizontal polarization probe and the vertical polarization probe are arranged at intervals, and the intervals between any two adjacent horizontal polarization probes and the vertical polarization probes are equal.

[0010] Furthermore, a reference probe is provided on the sampling ring, and the reference probe is provided on the other side of the sampling ring.

[0011] Furthermore, the antenna test system includes a pole, the antenna under test is arranged on the top of the pole, the pole rotates around the central axis in the longitudinal direction, the rotation angle is 0-360 degrees, and the pole rotates to drive the antenna under test to rotate.

[0012] The above-mentioned single-polarization spherical near-field sampling method includes the following steps:

[0013] Step S1. symmetrically installing the horizontal polarization probe and the vertical polarization probe;

[0014] Step S2. performing consistency calibration on the horizontal polarization probe and the vertical polarization probe respectively to obtain calibration data of each detection probe;

[0015] Step S3. Setting the antenna under test, activating the horizontal polarization probe and the vertical polarization probe, and rotating the antenna under test so that the horizontal polarization probe and the vertical polarization probe respectively obtain the horizontal sampling signal data and the vertical sampling signal data;

[0016] Step S4. performing interpolation processing on the horizontal sampling signal data and the vertical sampling signal data;

[0017] Step S5: Using the processed horizontal sampling signal data and the vertical sampling signal data to synthesize the cross-polarization components of each sampling position.

[0018] The above-mentioned single-polarization spherical near-field sampling method performs consistency calibration on multiple horizontal polarization probes and multiple vertical polarization probes before sampling the antenna under test to obtain calibration data for correcting the horizontal sampling signal data and the vertical sampling signal data.

[0019] Furthermore, a standard antenna with known characteristics and standard data is selected according to requirements, and the standard antenna is aligned with the horizontal polarization probe and the vertical polarization probe, so that the horizontal polarization probe and the vertical polarization probe obtain the horizontal calibration sampling signal data and the vertical calibration sampling signal data of the standard antenna, and the horizontal calibration sampling signal data and the vertical calibration sampling signal data are respectively compared with the standard data to obtain the calibration data of each detection probe.

[0020] Furthermore, the standard antenna is an antenna with a known radiation pattern and calibrated by a professional organization, such as a standard dipole antenna, a loop antenna, a spherical antenna, a cross-polarization antenna, a horn antenna, a ridged horn antenna, a double-ridged horn antenna or a rectangular waveguide antenna.

[0021] The present invention according to the above scheme has the following beneficial effects:

[0022] 1. In the present invention, the horizontal polarization probes and the vertical polarization probes are symmetrically distributed. Through the special distribution of the single polarization probes, the same effect as the traditional dual polarization sampling is achieved.

[0023] 2. The present invention uses a single-polarization probe to replace the dual-polarization probe, and changes the dual-channel consistency calibration to a single-channel consistency calibration, which reduces the calibration difficulty and calibration error of the multi-probe system. It also does not need to consider the mutual influence of the dual channels in actual situations, ensuring the purity of the sampled signal. At the same time, since the number of hardware channels in the antenna test system is reduced, the system hardware cost is also reduced.

[0024] 3. The horizontally polarized probes and vertically polarized probes in the present invention are symmetrically distributed. One implementation method is a semi-circular distribution. This distribution of detection probes can reduce the antenna test system's dependence on the darkroom, reduce the darkroom volume, and further reduce the hardware cost of the antenna test system. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0026] Figure 1 Flowchart of the single-polarization spherical near-field sampling method.

[0027] Figure 2 This is a structural diagram of the symmetrical distribution of probes in Example 1.

[0028] Figure 3 This is a structural diagram of the semi-circular distribution of probes in Example 2.

[0029] Among them, the reference numerals in the figures are:

[0030] 1. Sampling ring; 2. Pole; 3. Vertical polarization probe; 4. Horizontal polarization probe; 5. Reference probe. DETAILED DESCRIPTION

[0031] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present invention more clearly understood, the present invention is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0032] The antenna test system for single-polarization spherical near-field sampling of the present invention includes:

[0033] Sampling ring 1, used to install the detection probes so that the vibration surfaces of all the detection probes are located on the same ring;

[0034] Pole 2, which is used to install and rotate the antenna under test and the standard antenna. The antenna under test is placed at the center of sampling ring 1.

[0035] The vertical polarization probe 3, i.e., a probe with vertical polarization distribution, is used to detect the vertical component of the electromagnetic wave emitted by the antenna under test;

[0036] The horizontal polarization probe 4, i.e., a probe with horizontal polarization distribution, is used to detect the horizontal component of the electromagnetic wave emitted by the antenna under test;

[0037] The reference probe 5 , that is, the detection probe used for detection reference, is used to verify the accuracy of the test system. In this application, the reference probe 5 is a horizontally polarized reference probe.

[0038] The horizontal polarization probe 4 and the vertical polarization probe 3 are both single-polarization probes, and only have detection data of a single channel.

[0039] The holding pole 2 can be located on a certain arc-shaped slide rail structure. During testing, for convenience, the holding pole 2 is set at the lowest point of the slide rail structure.

[0040] A single-polarization spherical near-field sampling method, the sampling process operation steps include:

[0041] Step S1. symmetrically install the horizontal polarization probe 4 and the vertical polarization probe 3 on the sampling ring 1 of the antenna test system. The distribution of the vertical polarization probe 3 and the horizontal polarization probe 4 can be specifically implemented in the following two embodiments:

[0042] Example 1:

[0043] like Figure 2 As shown, multiple vertical polarization probes 3 are set on one side of the ring, and the vertical polarization probes 3 are spaced evenly apart. Multiple horizontal polarization probes 4 are set on the other side of the sampling ring 1, and the horizontal polarization probes 4 are spaced evenly apart. The vertical polarization probes 3 and the horizontal polarization probes 4 are set on both sides of the sampling ring 1 and are symmetrically distributed.

[0044] Example 2:

[0045] like Figure 3 As shown, the sampling ring 1 is provided with multiple vertical polarization probes 3 and multiple horizontal polarization probes 4. The vertical polarization probes 3 and horizontal polarization probes 4 are spaced apart. A horizontal polarization probe 4 is provided between two vertical polarization probes 3, and another vertical polarization probe 3 is provided between two horizontal polarization probes 4. The vertical polarization probes 3 and horizontal polarization probes 4 are provided only on one side of the sampling ring 1, while a horizontal polarization reference probe is provided on the upper portion of the other side.

[0046] Step S2: Install a standard antenna on mast 2 of the antenna test system, centered in sampling loop 1. Mast 2 is rotated 360°, driving the standard antenna's rotation 360°. The horizontal polarization probe 4 and the vertical polarization probe 3 then obtain horizontal and vertical calibration sampled signal data, respectively. The horizontal and vertical calibration sampled signal data measured by each test probe are compared with the standard data from the standard antenna. The difference is the calibration data for each test probe. Subsequent data obtained by each test probe is corrected using this calibration data.

[0047] When installing a standard antenna, install it on pole 2. Establish a three-dimensional coordinate system with the location of the standard antenna or test antenna on pole 2 as the origin. The Z axis is a line perpendicular to the plane where the standard antenna or test antenna is located on pole 2.

[0048] Different standard antennas are used, and the setting methods of the standard antennas are different:

[0049] When the standard antenna is a dipole antenna, the dipole antenna is placed at the center of pole 2, which is the set test center, and the radial direction of the dipole antenna points in the X-axis, Y-axis, and Z-axis directions;

[0050] When the standard antenna is a horn antenna, the horn antenna is placed at the test center with the opening pointing to the ±X axis, ±Y axis, and ±Z axis;

[0051] When the standard antenna is a spherical antenna, the distance between the surface of the spherical antenna and the test center is the same;

[0052] When the standard antenna is a cross-polarized antenna, rectangular waveguide antenna, ridged horn antenna, or double-ridged horn antenna, these standard antennas are placed at the test center with their openings pointing toward the ±X, ±Y, and ±Z axes. During the calibration process, they need to be rotated 90° along each coordinate axis.

[0053] Step S3: Replace the standard antenna with the antenna under test. Activate the horizontal polarization probe 4 and the vertical polarization probe 3 to begin spherical near-field sampling. Rotate the mast 2 360°, driving the antenna under test 360° as well. The horizontal polarization probe 4 and the vertical polarization probe 3 obtain horizontal and vertical sampled signal data, respectively. Both the directly obtained horizontal and vertical sampled signal data require correction. After calibration, subsequent processing is performed.

[0054] Step S4: performing interpolation processing on the horizontal sampling signal data and the vertical sampling signal data.

[0055] Step S5. Use the processed horizontal sampling signal data and vertical sampling signal data to synthesize the cross-polarization components of each sampling position to obtain the near-field data of the antenna under test (equivalent to the near-field radiation pattern), and obtain the far-field data of the antenna under test (equivalent to the far-field radiation pattern) through the near-far-field conversion algorithm.

[0056] A method for synthesizing single-polarized detection probes is used to perform vector synthesis on data obtained by two near-field detection probes, horizontally polarized and vertically polarized, to form a cross-polarized component. In order to improve the accuracy of the calculation, the two single-polarized components of the antenna under test are corrected and interpolated, and the dual-channel probe calibration is changed to a single-channel calibration. Then, the far-field data is obtained through near-far field conversion. The overall idea of the present invention is: in order to reduce equipment requirements, the data obtained by direct detection is obtained as much as possible through calculation, the data required for the far field is changed to the data required for the near field through near-far field conversion, the dual-channel data is obtained through single-channel data, and the cross-polarized data is obtained through single-polarized data, thereby reducing the difficulty and complexity of the test, that is, more accurate far-field data is easily obtained with the accuracy of the near-field data.

[0057] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A single-polarization spherical near-field sampling method, characterized in that: Symmetrically distributed horizontal polarization probes and vertical polarization probes are set at the near-zone spherical position of the antenna under test, so that the antenna under test rotates. The horizontal polarization probes and the vertical polarization probes respectively obtain horizontal sampling signal data and vertical sampling signal data of the antenna under test. The horizontal sampling signal data and the vertical sampling signal data are interpolated and synthesized to obtain cross-polarization components at each sampling position, so as to obtain near-field data of the antenna under test.

2. The single-polarization spherical near-field sampling method according to claim 1, characterized in that: The antenna under test is placed at the test center of the antenna test system. The horizontal polarization probe and the vertical polarization probe are both arranged on a sampling ring of the antenna test system. The test center coincides with the center position of the sampling ring.

3. The single-polarization spherical near-field sampling method according to claim 2, characterized in that: The horizontal polarization probe and the vertical polarization probe are respectively arranged on both sides of the sampling ring. The setting position of the horizontal polarization probe is symmetrical to the setting position of the vertical polarization probe, and the spacing distance between two adjacent horizontal polarization probes is equal to the spacing distance between two adjacent vertical polarization probes.

4. The single-polarization spherical near-field sampling method according to claim 2, wherein: The horizontal polarization probe and the vertical polarization probe are both arranged on one side of the sampling ring. The horizontal polarization probe and the vertical polarization probe are arranged at intervals, and the intervals between any two adjacent horizontal polarization probes and the vertical polarization probes are equal.

5. A single-polarization spherical near-field sampling method according to claim 4, characterized in that: A reference probe is also provided on the sampling ring, and the reference probe is provided on the other side of the sampling ring.

6. The single-polarization spherical near-field sampling method according to claim 2, characterized in that: The antenna test system includes a pole, the antenna under test is arranged on the top of the pole, and the pole rotates around the central axis in the longitudinal direction with a rotation angle of 0-360 degrees. The rotation of the pole drives the antenna under test to rotate.

7. The single-polarization spherical near-field sampling method according to claim 1, characterized in that: The sampling process steps include Step S1. symmetrically installing the horizontal polarization probe and the vertical polarization probe; Step S2. performing consistency calibration on the horizontal polarization probe and the vertical polarization probe respectively to obtain calibration data of each detection probe; Step S3. Setting the antenna under test, activating the horizontal polarization probe and the vertical polarization probe, and rotating the antenna under test so that the horizontal polarization probe and the vertical polarization probe respectively obtain the horizontal sampling signal data and the vertical sampling signal data; Step S4. performing interpolation processing on the horizontal sampling signal data and the vertical sampling signal data; Step S5: Using the processed horizontal sampling signal data and the vertical sampling signal data to synthesize the cross-polarization components of each sampling position.

8. The single-polarization spherical near-field sampling method according to claim 1, characterized in that: Before sampling the antenna under test, a plurality of horizontal polarization probes and a plurality of vertical polarization probes are respectively calibrated to obtain calibration data for correcting the horizontal sampling signal data and the vertical sampling signal data.

9. The single-polarization spherical near-field sampling method according to claim 1, characterized in that: A standard antenna with known characteristics and standard data is selected according to requirements, and the standard antenna is aligned with the horizontal polarization probe and the vertical polarization probe. The horizontal polarization probe and the vertical polarization probe obtain horizontal calibration sampling signal data and vertical calibration sampling signal data of the standard antenna. The horizontal calibration sampling signal data and the vertical calibration sampling signal data are respectively compared with the standard data to obtain calibration data of each detection probe.

10. The single-polarization spherical near-field sampling method according to claim 9, characterized in that: The standard antenna is a standard dipole antenna, a loop antenna, a spherical antenna, a cross-polarization antenna, a horn antenna, a ridged horn antenna, a double-ridged horn antenna or a rectangular waveguide antenna. The standard antenna is an antenna with a known radiation pattern and calibrated by a professional organization.

Images