Antenna spherical scanning measurement method, apparatus and computer program
By determining sampling points on the spherical surface of the test object and performing data mapping and compensation on the measurement sphere, the problems of low measurement accuracy and efficiency in the antenna spherical scanning measurement method are solved, and high-precision antenna testing is achieved.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- GENERAL TEST SYST
- Filing Date
- 2025-11-28
- Publication Date
- 2026-07-24
Smart Images
Figure CN121410378B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of communication technology, and in particular to an antenna spherical scanning measurement method, apparatus, and computer program. Background Technology
[0002] Antennas are a crucial component of wireless communication systems. Antenna measurement is one of the main methods for evaluating antenna radiation characteristics, providing important references for accurately assessing antenna performance and optimizing antenna design. Depending on the measurement distance, antenna measurement methods include far-field measurement, near-field measurement, and compact field measurement. Near-field measurement utilizes a sampling probe to collect data on the antenna's radiation field on the scanning surface of the near-field radiation region, and then uses near-field-to-far-field transformation to obtain the antenna's far-field characteristics. Compared to other measurement methods, near-field measurement has many advantages, such as avoiding external interference when measuring indoors, and with the development of near-field technology, it offers higher accuracy than other measurement methods.
[0003] Depending on the shape of the near-field scanning surface, near-field measurements include planar near-field measurements, cylindrical near-field measurements, and spherical near-field measurements. Spherical near-field measurements are suitable for almost any type of antenna radiation, a significant advantage compared to planar and cylindrical near-field measurements. Figure 1 As shown, in the Spherical Near-field Test, the antenna under test (AUT) is placed at the origin of the spherical measurement coordinate system. The scanning surface of the probe is a sphere that completely surrounds the AUT (hereinafter referred to as the "wrapped sphere"). The measurement probe performs a near-field scan on this sphere to accurately obtain the three-dimensional radiation characteristics of the antenna. This method has strong adaptability and is suitable for measurements with complex antenna shapes and high precision requirements.
[0004] However, for devices such as satellites, aircraft, ships, and vehicles where the antenna itself is much smaller than the carrier, the antenna under test (AUT) will inevitably deviate from the center of the measurement coordinate system during near-field measurements of the antenna spherical surface. Taking a vehicle as an example, refer to... Figure 2 To meet communication needs in various scenarios, vehicles integrate multiple types of antennas, including 5G, cellular, and GNSS antennas. These antennas are deployed in locations on the vehicle, including but not limited to: directly above the roof, behind the roof, the sunroof, the left and right rearview mirrors, and the front bumper. This makes it impossible to center all antennas on the measurement coordinate system during testing. Furthermore, when the size of the measurement turntable is limited, it is also impossible to move the vehicle to center antennas such as those on the front and rear bumpers on the measurement coordinate system. This situation where the AUT (Automatic Under Test) deviates from the center of the measurement coordinate system is technically referred to as the "eccentricity problem."
[0005] One intuitive technical approach to solving the eccentricity problem is to increase the measurement radius. The core principle is to use the far-field approximation to overcome the error caused by geometric deviation. The magnitude of the error caused by eccentricity ( It mainly depends on the offset. With the measured radius ratio Increase the measurement radius. This directly reduces the ratio. However, in reality, due to limitations in darkroom size or the ability to install large-radius scanning rigs, the physical feasibility of increasing the measurement radius is very low.
[0006] Another solution to the eccentricity problem is to enlarge the enclosing sphere to completely surround the carrier. Taking a vehicle as an example, refer to... Figure 3 The original test component was one of the vehicle's antennas. When an eccentricity problem occurred, refer to... Figure 4 The approach involves expanding the sphere to completely enclose the vehicle, treating the entire vehicle as the radiator, thus eliminating the eccentricity issue. However, this method has the following problems: First, the sphere is defined to describe the size of the radiator, thereby determining the near-field sampling interval (similar to determining the sampling frequency by evaluating the upper frequency limit of the signal in the time domain). In other words, the sphere is essentially a closest estimate of the antenna aperture from a measurement perspective; a larger sphere implies a larger antenna aperture. However, most of the area within the expanded sphere does not participate in radiation or radiate current. Therefore, the expanded sphere does not describe the antenna's own radiation characteristics, which is physically unreasonable and cannot guarantee measurement accuracy. Second, ... Figure 3 and Figure 4 The spherical grid illustrates the sampling interval. When the sphere expands, it is equivalent to increasing the aperture of the antenna under test, and the number of sampling points required also increases dramatically. This will lead to a sharp increase in measurement time and reduce measurement efficiency.
[0007] In summary, traditional antenna spherical scanning measurement methods suffer from technical problems such as poor measurement accuracy and low measurement efficiency. Summary of the Invention
[0008] In view of this, the purpose of the present invention is to provide an antenna spherical scanning measurement method, apparatus and computer program to alleviate the technical problems of poor measurement accuracy and low measurement efficiency of traditional antenna spherical scanning measurement methods.
[0009] In a first aspect, embodiments of the present invention provide an antenna spherical scanning measurement method, comprising:
[0010] A first sampling point is determined on the spherical surface of the sphere enclosing the test object, wherein the sphere enclosing the test object at least completely surrounds the antenna under test, and the interval of the first sampling point follows the Nyquist spherical sampling theorem;
[0011] The first sampling point is mapped onto the measuring sphere to obtain the second sampling point, wherein the measuring sphere at least completely surrounds the object being measured.
[0012] The probe is used to scan and sample at the second sampling point to obtain the scanning data of the spherical surface being measured;
[0013] The scan data of the measured sphere is compensated to obtain compensated scan data;
[0014] If the second sampling point satisfies the far-field condition of the antenna under test, then the compensated scanning data is used as the far-field characteristic of the antenna under test.
[0015] If the second sampling point does not meet the far-field conditions of the antenna under test, the spherical wave expansion coefficient of the antenna under test is calculated based on the compensated scanning data, and the far-field characteristics of the antenna under test are calculated using the spherical wave expansion coefficient.
[0016] Further, mapping the first sampling point onto the measurement sphere includes:
[0017] Connect the center of the sphere enclosed by the test piece to any one of the first sampling points. The resulting line segment continues to extend at the position of the first sampling point, and the intersection with the surface of the measured sphere is taken as the second sampling point corresponding to the first sampling point.
[0018] Furthermore, the method also includes:
[0019] Determine whether the second sampling point satisfies the far-field condition of the antenna under test;
[0020] If not satisfied, the diameter of the measuring sphere is calculated based on the position information of the sphere wrapped by the test piece, the position information of the origin of the measurement coordinate system, and the position information of the first sampling point, when the far-field condition of the antenna under test is satisfied, wherein the origin of the measurement coordinate system is the center of the measuring sphere.
[0021] If the diameter is within the adjustable range of the measuring sphere, the diameter of the measuring sphere is adjusted so that the second sampling point satisfies the far-field condition of the antenna under test.
[0022] Further, determining whether the second sampling point satisfies the far-field condition of the antenna under test includes:
[0023] The minimum second sampling distance is calculated based on the position information of the center of the ball wrapped by the test piece and the position information of the second sampling point, wherein the minimum second sampling distance is the minimum distance from the second sampling point to the center of the ball wrapped by the test piece;
[0024] Determine whether the minimum second sampling distance is greater than ,in, This indicates the maximum size of the antenna under test. This indicates the wavelength of the antenna under test;
[0025] If it is greater than, then the second sampling point satisfies the far-field condition of the antenna under test;
[0026] If it is not greater than, then the second sampling point does not satisfy the far-field condition of the antenna under test.
[0027] Furthermore, mapping the first sampling point onto the measurement sphere also includes:
[0028] The diameter of the measuring sphere is calculated based on the position information of the center of the sphere enclosed by the test object, the position information of the origin of the measurement coordinate system, and the position information of the first sampling point, when the far-field conditions of the antenna under test are satisfied.
[0029] If the diameter is within the adjustable range of the measuring sphere, then adjust the diameter of the measuring sphere so that the measuring sphere satisfies the far-field conditions of the antenna under test;
[0030] Connect the center of the sphere enclosed by the test piece to any one of the first sampling points. The resulting line segment continues to extend at the position of the first sampling point, and the intersection with the surface of the measured sphere is taken as the second sampling point corresponding to the first sampling point.
[0031] Furthermore, a probe is used to scan and sample at the second sampling point to obtain scan data of the measured sphere, including:
[0032] At each of the second sampling points, the probe is pointed towards the center of the measuring sphere to perform scanning sampling, thereby obtaining the scanning data of the first direction;
[0033] or
[0034] At each of the second sampling points, the probe is pointed towards the center of the sphere enclosed by the test object to perform scanning sampling, thereby obtaining the second-pointing scanning data;
[0035] The scan data of the first pointing direction or the scan data of the second pointing direction are used as the scan data of the measuring sphere.
[0036] Furthermore, when the scan data of the measuring sphere is the scan data of the first pointing direction, compensation is performed on the scan data of the measuring sphere, including:
[0037] Based on the angle between the main radiation direction of the probe and the direction of the line connecting the probe and the center of the sphere enclosed by the test object at each second sampling point, and the antenna gain pattern of the probe, compensation based on probe gain is performed, and compensation based on path loss difference is performed based on the distance between each second sampling point and the sphere enclosed by the test object, to obtain the compensated scanning data.
[0038] Furthermore, when the scan data of the measuring sphere is the scan data of the second direction, compensation is performed on the scan data of the measuring sphere, including:
[0039] Based on the distance between each of the second sampling points and the sphere enclosed by the test object, a calibration calculation based on the path loss difference is performed on the second pointing scan data to obtain the compensated scan data.
[0040] Furthermore, when the scan data of the measuring sphere is the scan data of the second direction, compensation for the scan data of the measuring sphere also includes:
[0041] The scan data pointed to by the second direction is used as the compensated scan data.
[0042] Furthermore, the spherical wave expansion coefficient of the antenna under test is calculated based on the compensated scanning data, and the far-field characteristics of the antenna under test are calculated using the spherical wave expansion coefficient, including:
[0043] The spherical wave expansion coefficient of the antenna under test is calculated based on the compensated scan data and the position of the second sampling point, and the far-field characteristics of the antenna under test are calculated using the spherical wave expansion coefficient.
[0044] Secondly, embodiments of the present invention also provide an antenna spherical scanning measurement device, comprising: a probe, a scanning mechanism, and a host computer, wherein the scanning mechanism is used to drive the probe to move, and the antenna spherical scanning measurement device is used to perform the antenna spherical scanning measurement method described in any one of the first aspects above.
[0045] Thirdly, embodiments of the present invention also provide a computer program, which, when called and run by a control processor, causes the control processor to run the antenna spherical scanning measurement method described in any of the first aspects above.
[0046] In this embodiment of the invention, an antenna spherical scanning measurement method is provided, comprising: determining a first sampling point on the spherical surface of a sphere enclosing a device under test (DUT), wherein the sphere enclosing the DUT at least completely surrounds the antenna under test, and the interval of the first sampling point follows the Nyquist spherical sampling theorem; mapping the first sampling point onto the measurement sphere to obtain a second sampling point, wherein the measurement sphere at least completely surrounds the sphere enclosing the DUT; using a probe to perform scanning sampling at the second sampling point to obtain scanning data of the measurement sphere; compensating the scanning data of the measurement sphere to obtain compensated scanning data; if the second sampling point satisfies the far-field condition of the antenna under test, then the compensated scanning data is used as the far-field characteristic of the antenna under test; if the second sampling point does not satisfy the far-field condition of the antenna under test, then the spherical wave expansion coefficient of the antenna under test is calculated based on the compensated scanning data, and the far-field characteristic of the antenna under test is calculated using the spherical wave expansion coefficient. As described above, in the antenna spherical scanning measurement method of the present invention, a first sampling point is first determined on the spherical surface of the device under test (DUT) enclosing the antenna under test. The DUT enclosing the antenna under test must at least completely surround the antenna under test. Then, the first sampling point is mapped onto the measurement spherical surface to obtain a second sampling point. A probe is then used to scan and sample at the second sampling point to obtain the scanning data of the measurement spherical surface. The scanning data of the measurement spherical surface is then compensated to obtain compensated scanning data. Finally, the far-field characteristics of the antenna under test are obtained based on the compensated scanning data. It can be seen that the DUT enclosing the antenna under test can completely surround the antenna under test, which has good engineering feasibility, conforms to the actual physical radiation of the antenna under test, ensures the accuracy of the test, and does not increase the number of near-field sampling points, thus improving the test efficiency and alleviating the technical problems of poor measurement accuracy and low measurement efficiency of traditional antenna spherical scanning measurement methods. Attached Figure Description
[0047] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.
[0048] Figure 1 A schematic diagram of spherical near-field measurements provided by conventional techniques;
[0049] Figure 2 A schematic diagram of spherical near-field measurement of vehicles using conventional techniques;
[0050] Figure 3 A schematic diagram of the spherical sampling interval for vehicle spherical near-field measurements provided by conventional technologies;
[0051] Figure 4A schematic diagram of another spherical sampling interval for vehicle spherical near-field measurement provided by conventional technology;
[0052] Figure 5 A flowchart of an antenna spherical scanning measurement method provided in an embodiment of the present invention;
[0053] Figure 6 A schematic diagram of the measurement coordinate system and the unfolded coordinate system provided in an embodiment of the present invention;
[0054] Figure 7 This is a schematic diagram illustrating the mapping of a first sampling point to a second sampling point in an embodiment of the present invention. Detailed Implementation
[0055] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.
[0056] Traditional antenna spherical scanning measurement methods suffer from poor accuracy and low efficiency.
[0057] Based on this, in the antenna spherical scanning measurement method of the present invention, a first sampling point is first determined on the spherical surface of the device under test (DUT) enclosing the antenna under test (TUT). The DUT enclosing the antenna under test (TUT) at least completely surrounds the antenna under test (TUT). Then, the first sampling point is mapped onto the measurement spherical surface to obtain a second sampling point. A probe is then used to scan and sample at the second sampling point to obtain scanning data of the measurement spherical surface. The scanning data of the measurement spherical surface is then compensated to obtain compensated scanning data. Finally, the far-field characteristics of the antenna under test (TUT) are obtained based on the compensated scanning data. It is evident that the DUT enclosing the antenna under test (TUT) can completely surround the antenna under test (TUT), which has good engineering feasibility, conforms to the actual physical radiation of the antenna under test (TUT), ensures the accuracy of the test, and improves the test efficiency without increasing the number of near-field sampling points.
[0058] To facilitate understanding of this embodiment, a detailed description of an antenna spherical scanning measurement method disclosed in this embodiment of the invention will be provided first.
[0059] Example 1:
[0060] According to an embodiment of the present invention, an embodiment of an antenna spherical scanning measurement method is provided. It should be noted that the steps shown in the flowchart in the accompanying drawings can be executed in a computer system such as a set of computer-executable instructions. Furthermore, although a logical order is shown in the flowchart, in some cases, the steps shown or described may be executed in a different order than that shown here.
[0061] Figure 5This is a flowchart of an antenna spherical scanning measurement method according to an embodiment of the present invention, such as... Figure 5 As shown, the method includes the following steps:
[0062] Step S502: Determine the first sampling point on the spherical surface of the sphere enclosing the test object, wherein the sphere enclosing the test object at least completely surrounds the antenna under test, and the interval of the first sampling point follows the Nyquist spherical sampling theorem;
[0063] For details, please refer to Figure 6 A measurement coordinate system O-xyz with the center of the measurement system as its origin, and an expanded coordinate system O'-x'y'z' with the center O' of the antenna under test as its origin, are defined. In the expanded coordinate system O'-x'y'z', a sphere completely surrounding the antenna under test is defined with O' as its center. In the measurement coordinate system O-xyz, a measurement sphere for probe scanning is defined with O as its center. It can be understood that both the sphere surrounding the antenna under test and the measurement sphere are virtual spheres defined for ease of description and are not physical entities within the test system.
[0064] When the sphere enclosing the device under test (DUT) completely surrounds the antenna under test (AUT), the diameter of the sphere enclosing the DUT is the maximum size of the AUT. It should be noted that in some cases, such as when the carrier causes a certain degree of reflection and scattering of the antenna radiation, the sphere enclosing the DUT can be appropriately enlarged to cover the effects of these reflections and scattering. Considering the cost and efficiency of the test, the sphere enclosing the DUT does not need to be enlarged to cover the entire carrier of the AUT (i.e., the DUT itself), but this method does not impose this limitation. It is understood that the measuring sphere must at least surround the sphere enclosing the DUT. The interval of the first sampling point directly affects the accuracy of the test data, the quality of the near-field and far-field transformation results, and the test efficiency. An excessively large interval will lead to aliasing errors, making it impossible to accurately reconstruct the antenna radiation field; an excessively small interval will lead to excessively long test times, excessively large data volumes, and low efficiency. In related technologies, the sampling interval for spherical near-field measurements follows the Nyquist spherical sampling theorem. According to the Nyquist sampling theorem, the sampling interval Δ in the θ and φ directions must satisfy: ,in, This indicates the wavelength of the antenna under test. This indicates the maximum size of the antenna under test, which in this step can be considered as the diameter of the sphere enclosing the device under test.
[0065] Step S504: Map the first sampling point onto the measuring sphere to obtain the second sampling point, wherein the measuring sphere at least completely surrounds the object being measured.
[0066] Step S506: Use a probe to scan and sample at the second sampling point to obtain the scanning data of the spherical surface being measured;
[0067] Step S508: Compensate the scanning data of the measured sphere to obtain compensated scanning data;
[0068] Step S510: If the second sampling point satisfies the far-field condition of the antenna under test, then the compensated scanning data is used as the far-field characteristics of the antenna under test.
[0069] Step S512: If the second sampling point does not meet the far-field conditions of the antenna under test, the spherical wave expansion coefficient of the antenna under test is calculated based on the compensated scanning data, and the far-field characteristics of the antenna under test are calculated through the spherical wave expansion coefficient.
[0070] In this embodiment of the invention, an antenna spherical scanning measurement method is provided, comprising: determining a first sampling point on the spherical surface of a sphere enclosing a device under test (DUT), wherein the sphere enclosing the DUT at least completely surrounds the antenna under test, and the interval of the first sampling point follows the Nyquist spherical sampling theorem; mapping the first sampling point onto the measurement sphere to obtain a second sampling point, wherein the measurement sphere at least completely surrounds the sphere enclosing the DUT; using a probe to perform scanning sampling at the second sampling point to obtain scanning data of the measurement sphere; compensating the scanning data of the measurement sphere to obtain compensated scanning data; if the second sampling point satisfies the far-field condition of the antenna under test, then the compensated scanning data is used as the far-field characteristic of the antenna under test; if the second sampling point does not satisfy the far-field condition of the antenna under test, then the spherical wave expansion coefficient of the antenna under test is calculated based on the compensated scanning data, and the far-field characteristic of the antenna under test is calculated using the spherical wave expansion coefficient. As described above, in the antenna spherical scanning measurement method of the present invention, a first sampling point is first determined on the spherical surface of the device under test (DUT) enclosing the antenna under test. The DUT enclosing the antenna under test must at least completely surround the antenna under test. Then, the first sampling point is mapped onto the measurement spherical surface to obtain a second sampling point. A probe is then used to scan and sample at the second sampling point to obtain the scanning data of the measurement spherical surface. The scanning data of the measurement spherical surface is then compensated to obtain compensated scanning data. Finally, the far-field characteristics of the antenna under test are obtained based on the compensated scanning data. It can be seen that the DUT enclosing the antenna under test can completely surround the antenna under test, which has good engineering feasibility, conforms to the actual physical radiation of the antenna under test, ensures the accuracy of the test, and does not increase the number of near-field sampling points, thus improving the test efficiency and alleviating the technical problems of poor measurement accuracy and low measurement efficiency of traditional antenna spherical scanning measurement methods.
[0071] The above provides a brief overview of the antenna spherical scanning measurement method of the present invention. The specific details involved are described in detail below.
[0072] In an optional embodiment of the present invention, mapping the first sampling point onto the measurement sphere specifically includes the following steps:
[0073] Connect the center of the sphere enclosed by the test piece to any first sampling point. The resulting line segment continues to extend from the position of the first sampling point, and the intersection with the surface of the measured sphere is taken as the second sampling point corresponding to the first sampling point.
[0074] Specifically, starting from the center O' of the sphere enclosing the test piece, a ray along the direction from O' to any first sampling point intersects the surface of the measured sphere to obtain the corresponding second sampling point. Figure 7 As can be seen, the angular intervals of the first sampling points are uniformly distributed around the center of the sphere on the surface of the measured object, while the second sampling points are not uniformly distributed on the surface of the sphere. In step S502, the coordinates of the first sampling points in the unfolded coordinate system were obtained. In this step, the coordinates of the second sampling points in the measurement coordinate system are calculated according to relevant technical methods. For ease of calculation, when setting the two coordinate systems O-xyz and O'-x'y'z', the coordinate axes of the two coordinate systems can be set to the same direction.
[0075] In an optional embodiment of the present invention, the method further includes the following steps:
[0076] (1) Determine whether the second sampling point satisfies the far-field condition of the antenna under test;
[0077] Specifically, the steps include the following:
[0078] 11) Calculate the minimum second sampling distance based on the position information of the center of the ball wrapped by the test piece and the position information of the second sampling point, wherein the minimum second sampling distance is the minimum distance from the second sampling point to the center of the ball wrapped by the test piece;
[0079] 12) Determine if the minimum second sampling distance is greater than ,in, Indicates the maximum size of the antenna under test. Indicates the wavelength of the antenna under test;
[0080] 13) If it is greater than, then the second sampling point satisfies the far-field condition of the antenna under test;
[0081] 14) If it is not greater than, then the second sampling point does not meet the far-field condition of the antenna under test.
[0082] Reference Figure 7 The distance from the second sampling point to the center of the antenna under test is the second sampling distance. It can be seen that the second sampling distances corresponding to each second sampling point are different. In order for all second sampling points to meet the far-field conditions of the antenna under test, it means that the second sampling point closest to the center of the antenna under test needs to meet the far-field conditions, that is, the minimum second sampling distance needs to be greater than the far-field distance of the antenna under test (i.e., the second sampling point meets the far-field conditions of the antenna under test).
[0083] (2) If not satisfied, the diameter of the measuring sphere is calculated based on the position information of the sphere wrapped by the test piece, the position information of the origin of the measurement coordinate system and the position information of the first sampling point, where the far-field condition of the antenna under test is satisfied, and the origin of the measurement coordinate system is the center of the measuring sphere.
[0084] (3) If the diameter is within the adjustable range of the measuring sphere, adjust the diameter of the measuring sphere so that the second sampling point meets the far-field conditions of the antenna under test.
[0085] Specifically, the diameter of the measuring sphere is adjusted (through the mechanical structure of the probe scanning frame (i.e., the scanning mechanism) to the diameter of the measuring sphere that satisfies the far-field conditions of the antenna under test. This ensures that the second sampling point meets the far-field conditions of the antenna under test, meaning the measuring sphere satisfies the far-field conditions of the antenna under test.
[0086] In an optional embodiment of the present invention, mapping the first sampling point onto the measurement sphere further includes the following steps:
[0087] (1) Calculate the diameter of the measuring sphere that satisfies the far-field conditions of the antenna under test based on the position information of the center of the sphere enclosed by the test piece, the position information of the origin of the measurement coordinate system and the position information of the first sampling point;
[0088] (2) If the diameter is within the adjustable range of the measuring sphere, adjust the diameter of the measuring sphere so that the measuring sphere meets the far-field conditions of the antenna under test.
[0089] (3) Connect the center of the sphere enclosed by the test piece to any first sampling point. The resulting line segment continues to extend at the position of the first sampling point, and the intersection with the measured sphere is taken as the second sampling point corresponding to the first sampling point.
[0090] In an optional embodiment of the present invention, a probe is used to scan and sample at a second sampling point to obtain scan data of the measured sphere, specifically including the following steps:
[0091] (1) At each second sampling point, the probe is pointed to the center of the sphere being measured to perform scanning sampling, thereby obtaining the scanning data of the first direction;
[0092] or
[0093] (2) At each second sampling point, the probe is pointed at the center of the ball wrapped by the test piece to perform scanning sampling, and the second pointing scanning data is obtained;
[0094] (3) Use the scanning data of the first direction or the scanning data of the second direction as the scanning data of the sphere for measurement.
[0095] Specifically, the probe's orientation can be understood as the direction of maximum gain of the probe antenna's main radiating beam (main lobe), which is also the "optimal direction" of the probe's radiation. This direction is known after the measurement system has been verified and calibrated. The spatial position and orientation of the probe are controlled by the probe scanning frame of the measurement system (i.e., the antenna spherical scanning measurement device). In one embodiment, the probe scanning frame controls the probe's spatial position via the X / Y / Z linear axes of a three-axis motion system, and controls the probe's orientation via the azimuth / pitch / polarization rotation axis or the omnidirectional rotation axis. In another embodiment, the probe scanning frame controls the probe's spatial position via an arc-shaped guide rail in conjunction with the workpiece turntable, and controls the probe's orientation via the azimuth / pitch / polarization rotation axis or the omnidirectional rotation axis. In yet another embodiment, a multi-degree-of-freedom industrial robot is used to control the probe's spatial position and orientation.
[0096] For the first scanning method (scanning and sampling with the probe pointing towards the center of the sphere being measured), the mechanical control of the probe is simple. The angular offset between the probe and the AUT (antenna under test) is compensated for in the subsequent sampling data (i.e., the scanning data of the sphere being measured) calibration. However, when the offset is large or the AUT frequency is high, calibration is difficult to compensate for, which may lead to a decrease in measurement accuracy. For the second scanning method (scanning and sampling with the probe pointing towards the center of the sphere enclosed by the workpiece), the mechanical control of the probe is more complex, but the probe is always aligned with the normal to the AUT surface, satisfying the polarization alignment requirements of the measurement. The subsequent sampling data calibration is relatively simple, and the measurement accuracy is also higher. In actual implementation, a trade-off can be struck between the complexity of mechanical control and the measurement accuracy.
[0097] In an optional embodiment of the present invention, when the scanning data of the measured sphere is the scanning data of the first direction, compensation is performed on the scanning data of the measured sphere, specifically including the following steps:
[0098] Based on the angle between the main radiation direction of the probe and the direction of the line connecting the probe and the center of the sphere enclosed by the test object at each second sampling point, and the antenna gain pattern of the probe, compensation based on probe gain is performed, and compensation based on path loss difference is performed based on the distance between each second sampling point and the sphere enclosed by the test object, thus obtaining the compensated scan data.
[0099] It's understandable that the antenna gain pattern of the probe is not uniform. If the probe's main radiation direction does not point towards the center of the sphere enclosed by the test object, then the actual gain of the probe in the direction of the center of the sphere enclosed by the test object will be lower than the gain in the main radiation direction. Therefore, it is necessary to compensate for this gain loss based on the aforementioned angles and the probe's gain pattern.
[0100] It is understandable that if the sampling points are not equidistant, the path loss will be different, and compensation is needed to ensure that the scanned data is based on the same reference distance.
[0101] It should be noted that the above-mentioned compensation based on probe gain and compensation based on path loss difference are independent, that is, there is no order between the two.
[0102] In an optional embodiment of the present invention, when the scanning data of the measured sphere is the scanning data of the second direction, compensation is performed on the scanning data of the measured sphere, specifically including the following steps:
[0103] (1) Based on the distance between each second sampling point and the ball wrapped by the test object, the scanning data of the second direction is calibrated based on the difference in path loss to obtain the compensated scanning data.
[0104] In an optional embodiment of the present invention, when the scanning data of the measured sphere is the scanning data of the second direction, the compensation for the scanning data of the measured sphere further includes the following steps:
[0105] The scan data pointing in the second direction is used as the compensated scan data. It should be noted that compensation calculation for the scan data pointing in the second direction can be omitted in this step. Instead, when calculating the spherical wave expansion coefficient of the AUT later, the coefficient is solved using the matrix method from related techniques, based on the actual distance measured at the second sampling point. In other words, the spherical wave expansion coefficient of the AUT is directly calculated based on the scan data pointing in the second direction and the position of the second sampling point, and its far-field characteristics are calculated using the spherical wave expansion coefficient.
[0106] Compared to existing technologies where the antenna spherical scanning measurement method completely surrounds the entire carrier, this invention only requires the antenna under test (AUT) to be surrounded by the sphere. Therefore, this method offers superior engineering feasibility, accurately reflects the actual physical radiation characteristics of the AUT, ensures testing accuracy, and improves testing efficiency by eliminating the need for additional near-field sampling points. Furthermore, for large carriers such as vehicles, this method can flexibly perform far-field or near-field measurements based on the AUT's eccentricity, size, and the mechanical structure of the probe scanning frame.
[0107] Example 2:
[0108] This invention also provides an antenna spherical scanning measurement device, including: a probe, a scanning mechanism, and a host computer, wherein the scanning mechanism is used to drive the probe to move, and the antenna spherical scanning measurement device is mainly used to execute the antenna spherical scanning measurement method provided in Embodiment 1 of this invention.
[0109] Example 3:
[0110] This invention also provides a computer program that, when called and run by a control processor, causes the control processor to run the antenna spherical scanning measurement method provided in Embodiment 1 of this invention.
[0111] Furthermore, in the description of the embodiments of the present invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in the present invention based on the specific circumstances.
[0112] If the aforementioned functions are implemented as software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this invention, essentially, or the part that contributes to the prior art, or a portion of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of this invention. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.
[0113] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.
[0114] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.
Claims
1. A method for spherical scanning measurement of an antenna, characterized in that, include: A first sampling point is determined on the spherical surface of the sphere enclosing the test object, wherein the sphere enclosing the test object at least completely surrounds the antenna under test, and the interval of the first sampling point follows the Nyquist spherical sampling theorem; The first sampling point is mapped onto the measuring sphere to obtain the second sampling point, wherein the measuring sphere at least completely surrounds the object being measured. The probe is used to scan and sample at the second sampling point to obtain the scanning data of the spherical surface being measured; The scan data of the measured sphere is compensated to obtain compensated scan data; If the second sampling point satisfies the far-field condition of the antenna under test, then the compensated scanning data is used as the far-field characteristic of the antenna under test. If the second sampling point does not meet the far-field conditions of the antenna under test, the spherical wave expansion coefficient of the antenna under test is calculated based on the compensated scanning data, and the far-field characteristics of the antenna under test are calculated using the spherical wave expansion coefficient.
2. The method according to claim 1, characterized in that, Mapping the first sampling point onto the measurement sphere includes: Connect the center of the sphere enclosed by the test piece to any one of the first sampling points. The resulting line segment continues to extend at the position of the first sampling point, and the intersection with the surface of the measured sphere is taken as the second sampling point corresponding to the first sampling point.
3. The method according to claim 2, characterized in that, The method further includes: Determine whether the second sampling point satisfies the far-field condition of the antenna under test; If not satisfied, the diameter of the measuring sphere is calculated based on the position information of the sphere wrapped by the test piece, the position information of the origin of the measurement coordinate system, and the position information of the first sampling point, when the far-field condition of the antenna under test is satisfied, wherein the origin of the measurement coordinate system is the center of the measuring sphere. If the diameter is within the adjustable range of the measuring sphere, the diameter of the measuring sphere is adjusted so that the second sampling point satisfies the far-field condition of the antenna under test.
4. The method according to claim 3, characterized in that, Determining whether the second sampling point satisfies the far-field condition of the antenna under test includes: The minimum second sampling distance is calculated based on the position information of the center of the ball wrapped by the test piece and the position information of the second sampling point, wherein the minimum second sampling distance is the minimum distance from the second sampling point to the center of the ball wrapped by the test piece; Determine whether the minimum second sampling distance is greater than ,in, This indicates the maximum size of the antenna under test. This indicates the wavelength of the antenna under test; If it is greater than, then the second sampling point satisfies the far-field condition of the antenna under test; If it is not greater than, then the second sampling point does not satisfy the far-field condition of the antenna under test.
5. The method according to claim 2, characterized in that, Mapping the first sampling point onto the measurement sphere also includes: The diameter of the measuring sphere is calculated based on the position information of the center of the sphere enclosed by the test object, the position information of the origin of the measurement coordinate system, and the position information of the first sampling point, when the far-field conditions of the antenna under test are satisfied. If the diameter is within the adjustable range of the measuring sphere, then adjust the diameter of the measuring sphere so that the measuring sphere satisfies the far-field conditions of the antenna under test; Connect the center of the sphere enclosed by the test piece to any one of the first sampling points. The resulting line segment continues to extend at the position of the first sampling point, and the intersection with the surface of the measured sphere is taken as the second sampling point corresponding to the first sampling point.
6. The method according to claim 1, characterized in that, The probe is used to scan and sample at the second sampling point to obtain scan data of the spherical surface being measured, including: At each of the second sampling points, the probe is pointed towards the center of the measuring sphere to perform scanning sampling, thereby obtaining the scanning data of the first direction; or At each of the second sampling points, the probe is pointed towards the center of the sphere enclosed by the test object to perform scanning sampling, thereby obtaining the second-pointing scanning data; The scan data of the first pointing direction or the scan data of the second pointing direction are used as the scan data of the measuring sphere.
7. The method according to claim 6, characterized in that, When the scan data of the measuring sphere is the scan data of the first pointing direction, compensation is performed on the scan data of the measuring sphere, including: Based on the angle between the main radiation direction of the probe and the direction of the line connecting the probe and the center of the sphere enclosed by the test object at each second sampling point, and the antenna gain pattern of the probe, compensation based on probe gain is performed, and compensation based on path loss difference is performed based on the distance between each second sampling point and the sphere enclosed by the test object, to obtain the compensated scanning data.
8. The method according to claim 6, characterized in that, When the scan data of the measuring sphere is the scan data of the second direction, compensation is performed on the scan data of the measuring sphere, including: Based on the distance between each of the second sampling points and the sphere enclosed by the test object, a calibration calculation based on the path loss difference is performed on the second pointing scan data to obtain the compensated scan data.
9. The method according to claim 6, characterized in that, When the scan data of the measuring sphere is the scan data of the second direction, compensation for the scan data of the measuring sphere further includes: The scan data pointed to by the second direction is used as the compensated scan data.
10. The method according to claim 9, characterized in that, The spherical wave expansion coefficient of the antenna under test is calculated based on the compensated scanning data, and the far-field characteristics of the antenna under test are calculated using the spherical wave expansion coefficient, including: The spherical wave expansion coefficient of the antenna under test is calculated based on the compensated scan data and the position of the second sampling point, and the far-field characteristics of the antenna under test are calculated using the spherical wave expansion coefficient.
11. An antenna spherical scanning measurement device, characterized in that, include: The device comprises a probe, a scanning mechanism, and a host computer, wherein the scanning mechanism is used to move the probe, and the antenna spherical scanning measurement device is used to perform the antenna spherical scanning measurement method according to any one of claims 1 to 10.
12. A computer program, characterized in that, When the computer program is invoked and run by the control processor, the computer program causes the control processor to run the antenna spherical scanning measurement method according to any one of claims 1 to 10.