Device and method for testing antenna gain and polarization

Abstract

The embodiment of the invention provides a device and method for testing the gain and polarization of an antenna, and relates to the technical field of antenna testing, and the device comprises a measurement unit, a microwave camera obscura, a test probe, and a control assembly. The measuring unit is connected with the test probe and is used for outputting a radio frequency signal to the test probe; the testing probe and the tested antenna are placed in the microwave camera obscura, the testing probe is close to the tested antenna, the testing probe is used for converting a radio frequency signal output by the measuring unit into an electromagnetic signal for radiation, and the tested antenna receives the electromagnetic signal, converts the electromagnetic signal into the radio frequency signal and transmits the radio frequency signal to the measuring unit; and the control assembly is connected with the test probe and is used for controlling the test probe to move near the tested antenna according to a preset track. According to the technical scheme, the problems of high cost and large space limitation of a large-aperture antenna test site are solved, and the test method is simple and has relatively high application value.

Description

Technical Field

[0001] The present application relates to the technical field of antenna testing, and in particular to a device and method for testing antenna gain and polarization. Background Art

[0002] Currently, there are two commonly used testing methods for antenna gain: comparison method and absolute method.

[0003] The comparison method usually uses a standard antenna with known gain as a comparison standard to infer the gain of the antenna under test.

[0004] There are several types of absolute methods, including the two-antenna method (Fries formula, same antenna method), the three-antenna method (three equations to solve three unknowns), and the mirror method (with the help of a flat metal reflector). However, in order to obtain confirmation results of the measured antenna gain, both the comparison method and the absolute method are usually limited to the far-field environment.

[0005] In addition to antenna gain, antenna polarization is also an important performance indicator of the antenna. There are three types of antenna polarization: linear polarization, circular polarization, and elliptical polarization. The polarization characteristics of the antenna can generally be determined by the axial ratio. When the axial ratio is ≤7dB, the antenna under test is considered to have circular polarization characteristics. When the axial ratio is >7dB, the antenna under test is considered to have linear polarization characteristics. If you want to determine whether the antenna under test is linearly polarized or circularly polarized, and when determining the axial ratio of a circularly polarized antenna, you also need to do it in a far-field environment.

[0006] Commonly used antenna gain and antenna polarization tests have high requirements for the test site, especially when the antenna to be tested has a large aperture. Whether it is a standard far-field chamber or a compact field chamber, it requires a high construction cost. Therefore, there is an urgent need to find other simpler and lower-cost antenna gain and polarization test methods. Summary of the invention

[0007] The embodiments of the present application provide a device and method for testing antenna gain and polarization to solve the problems existing in the prior art.

[0008] Other features and advantages of the present application will become apparent from the following detailed description, or may be learned in part by the practice of the present application.

[0009] According to a first aspect of an embodiment of the present application, there is provided a device for testing antenna gain and polarization, comprising: a measuring unit, a microwave dark box, a test probe, and a control component; The measuring unit is connected to the test probe and is used to output a radio frequency signal to the test probe; The test probe and the antenna under test are placed in the microwave dark box, and the test probe is close to the antenna under test, wherein the test probe is used to convert the radio frequency signal output by the measuring unit into an electromagnetic signal for radiation, and the antenna under test receives the electromagnetic signal and converts it into a radio frequency signal for transmission to the measuring unit; The control component is connected to the test probe and is used to control the test probe to move near the antenna under test along a predetermined trajectory.

[0010] In some embodiments of the present application, based on the aforementioned solution, the control component includes: a manipulator controller and a first intelligent terminal; The first intelligent terminal is connected to the manipulator controller and is used to control the manipulator controller to move according to a predetermined trajectory; The manipulator controller is connected to the test probe and is used to drive the test probe to move along a predetermined trajectory.

[0011] In some embodiments of the present application, based on the aforementioned solution, the measuring unit includes a vector network instrument and a second intelligent terminal; The second intelligent terminal is connected to the vector network instrument to control the vector network instrument to perform radio frequency signal sampling; The vector network instrument is also connected to the test probe and the antenna under test respectively, and is used to output radio frequency signals to the test probe and receive radio frequency signals transmitted from the antenna under test.

[0012] In some embodiments of the present application, based on the aforementioned solution, the predetermined trajectory includes a plane movement trajectory, a cylindrical movement trajectory, and a spherical movement trajectory; The plane moving track refers to the test probe moving at a fixed distance above the antenna under test at uniform intervals. and The trajectory formed by the movement, where , , Indicates wavelength; The cylindrical surface movement trajectory refers to the test probe wrapping the cylindrical surface of the antenna under test according to the azimuth angle. , Towards The trajectory formed by evenly spaced movements, where , , is the beam constant, is the radius of the scanning cylinder; The spherical movement trajectory refers to the test probe wrapping the spherical surface of the antenna under test at a rotation angle interval , off-axis angle The trajectory formed by evenly spaced movements, where , , , is the number of modes of the spherical wave expansion, is the radius of the smallest sphere that encloses the antenna under test.

[0013] In some embodiments of the present application, based on the aforementioned solution, it further includes: a power module; The power supply module is connected to the measuring unit and the control component respectively.

[0014] According to a second aspect of an embodiment of the present application, a method for testing antenna gain and polarization is provided, which is applied to the device according to the first aspect, including: Placing the antenna under test in a microwave dark box, connecting the measuring unit to the test probe, and connecting the control component to the test probe; Adjust the distance between the test probe and the antenna under test, and move the test probe to the center position just above the antenna under test, record it as the origin, and then move the test probe along the predetermined trajectory; Set the test parameters according to the test frequency, antenna type and gain of the antenna under test; Perform a near-field scan and calculate the gain, polarization rotation and axial ratio of the antenna under test based on the scan results.

[0015] In some embodiments of the present application, based on the above solution, moving the test probe along a predetermined trajectory includes: The test probe is moved along a plane moving track, a cylindrical moving track or a spherical moving track.

[0016] In some embodiments of the present application, based on the aforementioned scheme, the test parameters include: near-field scanning distance, number of scanning points, vector network frequency and output power.

[0017] In some embodiments of the present application, based on the above solution, the near-field scanning includes: When the test probe is at the current position, a first near-field scan is performed to obtain a first complex signal at each scanning point; Return the test probe to the origin and rotate it by a preset angle to perform a second approach scan to obtain a second complex signal at each scan point.

[0018] In some embodiments of the present application, based on the above solution, the step of calculating the gain, polarization rotation direction and axial ratio of the antenna under test based on the scanning result includes: Determine a plane wave spectrum corresponding to the electric field according to the first complex signal of each scanning point and the second complex signal of each scanning point; Determine the antenna far field based on the relationship between the plane wave spectrum and the antenna far field pattern; The gain, polarization rotation direction and axial ratio of the antenna under test are calculated based on the antenna far field.

[0019] The technical solution of the present application only requires scanning the near field of the antenna under test in a relatively small space, and then using Fourier transform to obtain the far field of the antenna under test. The antenna gain, radiation pattern, axial ratio, and rotation direction can be directly, quickly and efficiently obtained based on the far field, thus solving the high cost and large space limitations of large-caliber antenna test sites. The test method is simple and has high application value.

[0020] It should be understood that the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The drawings herein are incorporated into the specification and constitute a part of the specification, showing embodiments consistent with the present application, and together with the specification, are used to explain the principles of the present application. Obviously, the drawings described below are only some embodiments of the present application, and for ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work. In the drawings: Figure 1 A schematic diagram of the structure of a device for testing antenna gain and polarization according to an embodiment of the present application is shown; Figure 2 A schematic diagram of a near-field plane scanning node according to an embodiment of the present application is shown; Figure 3 A schematic diagram of a near-field cylindrical scanning node according to an embodiment of the present application is shown; Figure 4 A schematic diagram of a near-field spherical scanning node according to an embodiment of the present application is shown; Figure 5 A schematic diagram of planar near-field scanning according to an embodiment of the present application is shown; Figure 6 A schematic diagram of a horn antenna according to an embodiment of the present application is shown; Figure 7 A schematic diagram showing a comparison between a full-wave simulation of a horn antenna according to an embodiment of the present application and a directional pattern calculated using the method of the present invention (Phi=0deg); Figure 8 A schematic diagram showing a comparison between a full-wave simulation of a horn antenna according to an embodiment of the present application and a directional pattern calculated using the method of the present invention (Phi=90deg); Fig. 9 A schematic diagram of calculating the aperture field distribution of a horn antenna using the method of the present invention according to an embodiment of the present application is shown; Fig.10A schematic diagram of calculating the three-dimensional axial ratio distribution of a horn antenna according to an embodiment of the present application using the method of the present invention is shown; Fig.11 A schematic diagram of calculating the two-dimensional axial ratio distribution of a horn antenna according to an embodiment of the present application using the method of the present invention (phi=0deg, 90deg); Fig.12 A schematic diagram of a dielectric-filled horn antenna according to an embodiment of the present application is shown; Fig.13 A schematic diagram showing the direction calculation of a dielectric-filled horn antenna using the method of the present invention according to an embodiment of the present application (Phi=0deg, 90deg); Fig.14 A schematic diagram showing the calculation of aperture field distribution of a dielectric-filled horn antenna using the method of the present invention according to an embodiment of the present application is shown; Fig.15 A schematic diagram showing a dielectric-filled horn antenna according to an embodiment of the present application using the method of the present invention to calculate the three-dimensional axial ratio distribution; Fig.16 A schematic diagram of two-dimensional axial ratio distribution (phi=0deg, 90deg) calculated using the method of the present invention for a dielectric-filled horn antenna according to an embodiment of the present application is shown.

[0022] Description of Reference Numerals 1- vector network instrument, 2- test probe, 3- antenna under test, 4- microwave darkroom, 5- manipulator controller, 6- computer, 7- power module. DETAILED DESCRIPTION

[0023] Example embodiments will now be described more fully with reference to the accompanying drawings. However, example embodiments can be implemented in a variety of forms and should not be construed as limited to the examples set forth herein; rather, these embodiments are provided so that this application will be more comprehensive and complete and fully convey the concept of the example embodiments to those skilled in the art.

[0024] In addition, described feature, structure or characteristic can be combined in one or more embodiments in any suitable manner. In the following description, many specific details are provided to provide a full understanding of the embodiments of the present application. However, those skilled in the art will appreciate that the technical scheme of the present application can be put into practice without one or more of the specific details, or other methods, components, devices, steps, etc. can be adopted. In other cases, known methods, devices, realizations or operations are not shown or described in detail to avoid blurring the various aspects of the application.

[0025] The block diagrams shown in the accompanying drawings are merely functional entities and do not necessarily correspond to physically independent entities. That is, these functional entities may be implemented in software form, or in one or more hardware modules or integrated circuits, or in different networks and / or processor devices and / or microcontroller devices.

[0026] The flowcharts shown in the accompanying drawings are only exemplary and do not necessarily include all the contents and operations / steps, nor must they be executed in the order described. For example, some operations / steps can be decomposed, and some operations / steps can be combined or partially combined, so the actual execution order may change according to actual conditions.

[0027] It should be noted that the terms "first", "second", etc. in the specification and claims of the present application and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the objects used in this way can be interchanged where appropriate, so that the embodiments of the present application described herein can be implemented in an order other than those shown or described.

[0028] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution in the embodiment of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiment of the present invention. Obviously, the described embodiment is only a part of the embodiment of the present invention, not all the embodiments. Based on the embodiment 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.

[0029] Some embodiments of the present application will be described in detail below in conjunction with the accompanying drawings. In the absence of conflict, the following embodiments and features in the embodiments may be combined with each other.

[0030] To solve the problems existing in the prior art, this embodiment provides a device for testing antenna gain and polarization, including: a measuring unit, a microwave dark box, a test probe and a control component; The measuring unit is connected to the test probe and is used to output a radio frequency signal to the test probe; The test probe and the antenna under test are placed in the microwave dark box, and the test probe is close to the antenna under test, wherein the test probe is used to convert the radio frequency signal output by the measuring unit into an electromagnetic signal for radiation, and the antenna under test receives the electromagnetic signal and converts it into a radio frequency signal for transmission to the measuring unit; The control component is connected to the test probe and is used to control the test probe to move near the antenna under test along a predetermined trajectory.

[0031] It should be noted that the test probe moves near the antenna under test in order to scan the antenna under test. During the specific scanning process, the electromagnetic signal emitted by the test probe will be received by the antenna under test, and the antenna under test will convert the received electromagnetic signal into a radio frequency signal and transmit it to the measurement unit.

[0032] It should be noted that the microwave darkroom is mainly used to shield electromagnetic signals, prevent surrounding reflected signals from interfering with test results, and prevent electromagnetic signal leakage.

[0033] It should be noted that during the operation of the device, the measuring unit outputs a radio frequency signal to the test probe. The test group converts the radio frequency signal into an electromagnetic signal and radiates it. The radiated electromagnetic signal is received by the antenna under test and converted into a radio frequency signal and transmitted to the measuring unit to complete the signal acquisition. The measuring unit performs calculations based on the radio frequency signal to implement the test.

[0034] In some feasible embodiments, based on the aforementioned solution, the control component includes: a manipulator controller and a first intelligent terminal; The first intelligent terminal is connected to the manipulator controller and is used to control the manipulator controller to move according to a predetermined trajectory; The manipulator controller is connected to the test probe and is used to drive the test probe to move along a predetermined trajectory.

[0035] It can be understood that in a microwave darkroom, the test probe is used to scan the antenna under test, so during the test process, the test probe needs to be moved. Therefore, in this embodiment, a corresponding manipulator controller and a first intelligent terminal are set up. The manipulator controller controls the movement of the test probe according to the instructions issued by the first intelligent terminal, thereby realizing the scanning of the antenna under test.

[0036] In some feasible embodiments, based on the above solution, the measuring unit includes a vector network instrument and a second intelligent terminal; The second intelligent terminal is connected to the vector network instrument to control the vector network instrument to perform radio frequency signal sampling; The vector network instrument is also connected to the test probe and the antenna under test respectively, and is used to output radio frequency signals to the test probe and receive radio frequency signals transmitted from the antenna under test.

[0037] It should be noted that, in order to save costs, the first intelligent terminal and the second intelligent terminal can use the same computer. The computer can control the manipulator controller to move along a predetermined trajectory, and can also control the vector network instrument to sample radio frequency signals.

[0038] For example, see Figure 1 , shows a schematic diagram of the structure of a device for testing antenna gain and polarization according to an embodiment of the present application.

[0039] like Figure 1 As shown, the device includes: a vector network instrument 1, a test probe 2, a tested antenna 3, a microwave darkroom 4, a manipulator controller 5 and a computer 6.

[0040] The antenna under test 3 and the test probe 2 are placed in a microwave dark box 4, and the test probe 2 is directly above the antenna under test 3, so as to scan the antenna under test 3. The vector network instrument 1 is connected to the test probe 2 and the antenna under test 3 respectively, and the vector network instrument 1 outputs a radio frequency signal to the test probe 2. The electromagnetic signal radiated by the test probe 2 is output in space and received by the antenna under test 3. The antenna under test 3 converts the electromagnetic wave radiated in space into a radio frequency signal and transmits it back to the vector network instrument 1.

[0041] The manipulator controller 5 is connected to the test probe 2 , and drives the test probe 2 to move by its own movement, so that the manipulator controller 5 can perform a plane, cylindrical or spherical scan on the antenna 3 under test.

[0042] The computer 6 is connected to the manipulator controller 5 and the vector network instrument 1 respectively. The computer 6 stores a program for controlling the manipulator controller 5 to move according to a predetermined trajectory. When the program is running, it will send corresponding control instructions to the manipulator controller 5; at the same time, the computer 6 will also control the vector network instrument 1 to sample the radio frequency signal.

[0043] It should be noted that, in this example, the test probe is a linearly polarized antenna.

[0044] In some feasible embodiments, based on the above scheme, the predetermined trajectory includes a plane movement trajectory, a cylindrical movement trajectory and a spherical movement trajectory; The plane moving track refers to the test probe moving at a fixed distance above the antenna under test at uniform intervals. and The trajectory formed by the movement, where , , Indicates wavelength; The cylindrical surface movement trajectory refers to the test probe wrapping the cylindrical surface of the antenna under test according to the azimuth angle. , Towards The trajectory formed by evenly spaced movements, where , , is the beam constant, is the radius of the scanning cylinder; The spherical movement trajectory refers to the test probe wrapping the spherical surface of the antenna under test at a rotation angle interval , off-axis angle The trajectory formed by evenly spaced movements, where , , , is the number of modes of the spherical wave expansion, is the radius of the smallest sphere that encloses the antenna under test.

[0045] It should be noted that the use of a moving track on a plane, a cylinder, or a spherical surface can realize scanning of the antenna under test on the plane, the cylinder, or the spherical surface, so that the acquired signal is more complete.

[0046] For example, see Figure 2 , shows a schematic diagram of a near-field plane scanning node according to an embodiment of the present application. The schematic diagram shows a plane scanning node for extracting the near field of the antenna under test by a test probe.

[0047] See also Figure 3 , shows a schematic diagram of a near-field cylindrical scanning node according to an embodiment of the present application. The schematic diagram shows a cylindrical scanning node for extracting the near field of the antenna under test by a test probe.

[0048] See also Figure 4 , shows a schematic diagram of a near-field spherical scanning node according to an embodiment of the present application. The schematic diagram shows a spherical scanning node for extracting the near field of the antenna under test by a test probe.

[0049] See also Figure 5 , shows a schematic diagram of planar near-field scanning according to an embodiment of the present application.

[0050] like Figure 2 As shown in the figure, when the test probe performs a plane scan, the test probe is at a fixed distance (usually 3 ~5 ), at evenly spaced intervals and ( , ) moves, and the moving process is as follows Figure 5 shown.

[0051] like Figure 3 As shown in the figure, when the test probe performs cylindrical scanning, the test probe wraps the cylindrical surface of the antenna under test according to the azimuth angle. , z direction Evenly spaced moves ( , , is the beam constant, is the scanning cylinder radius).

[0052] like Figure 4 As shown in the figure, when the test probe performs spherical scanning, the test probe wraps the spherical surface of the antenna under test at the rotation angle interval , off-axis angle Evenly spaced moves ( , , , is the number of modes of the spherical wave expansion, is the radius of the smallest sphere that surrounds the antenna under test).

[0053] In some feasible embodiments, based on the above solution, the device further includes: a power module; The power supply module is connected to the measuring unit and the control component respectively.

[0054] For example, Figure 1 The device also includes a power supply module 7, which is respectively connected to the vector network instrument 1, the antenna under test 3 (when the antenna under test is an active antenna) and the computer 6 to supply power to the vector network instrument 1, the antenna under test 3 (when the antenna under test is an active antenna) and the computer 6.

[0055] Based on the same inventive concept, an embodiment of the present application further provides a method for testing antenna gain and polarization, which is applied to the device as described in any of the above embodiments, and the method includes: Step S100, placing the antenna to be tested in a microwave dark box, connecting the measuring unit to the test probe, and connecting the control component to the test probe; Step S200, adjusting the distance between the test probe and the antenna under test, and moving the test probe to the center position just above the antenna under test, which is recorded as the origin, and then moving the test probe along a predetermined trajectory; Step S300, setting test parameters according to the test frequency, antenna type and gain of the antenna under test; Step S400: perform a near-field scan, and calculate the gain, polarization rotation direction, and axial ratio of the antenna under test based on the scan result.

[0056] In some feasible embodiments, based on the above solution, moving the test probe along a predetermined trajectory includes: The test probe is moved along a plane moving track, a cylindrical moving track or a spherical moving track.

[0057] It can be understood that moving the test probe along different moving trajectories can achieve scanning of different surfaces of the antenna under test.

[0058] In some feasible embodiments, based on the aforementioned scheme, the test parameters include: near-field scanning distance, number of scanning points, vector network frequency and output power.

[0059] In some feasible embodiments, based on the above solution, the near-field scanning includes: When the test probe is at the current position, a first near-field scan is performed to obtain a first complex signal at each scanning point; Return the test probe to the origin and rotate it by a preset angle to perform a second approach scan to obtain a second complex signal at each scan point.

[0060] It should be noted that the current position described in this embodiment refers to the position of the test probe after it has been moved.

[0061] In some feasible embodiments, based on the above solution, the step of calculating the gain, polarization rotation direction and axial ratio of the antenna under test based on the scanning result includes: Determine a plane wave spectrum corresponding to the electric field according to the first complex signal of each scanning point and the second complex signal of each scanning point; Determine the antenna far field based on the relationship between the plane wave spectrum and the antenna far field pattern; The gain, polarization rotation direction and axial ratio of the antenna under test are calculated based on the antenna far field.

[0062] A specific example of this method is provided below.

[0063] (a) Power on the test device and run the relevant test software; (b) The antenna under test is firmly mounted on the test platform in the microwave dark box, the RF port of the antenna under test is connected to the first port of the vector network instrument, and the test probe is connected to the second port of the vector network instrument; (c) Adjust the test platform and the test probe height so that the test probe is 3-5 times the wavelength away from the antenna under test, and move the test probe horizontally to the center position just above the antenna under test, and set this position as the origin; then move the test probe along a predetermined trajectory, which can be a plane movement trajectory, a cylindrical movement trajectory, or a spherical movement trajectory; (d) Set the appropriate near-field scanning distance and number of scanning points according to the test frequency, type and gain of the antenna under test; (e) Setting the vector network frequency and output power; (f) Perform near-field scanning and complete the near-field scanning to obtain the complex signal at each scanning point ; (g) Return to the probe origin, rotate the probe 90°, reset it to the probe origin, complete the near-field scan, and obtain the complex signal ; (h) Use the test software to calculate the axial ratio and obtain the axial ratio of the antenna under test.

[0064] The signal is reconstructed based on two calibration scan points and , we can directly get the plane wave spectrum corresponding to the electric field: .

[0065] The plane wave spectrum and the corresponding electric field have the following relationship: ; In the above formula, ; ; ; In the above formula, Represents the position vector from the spatial source point to the field point.

[0066] According to the relationship between the plane wave spectrum and the electric field, the electric field components of the x and y surfaces at plane Z=0 are obtained as follows: ; ; ; ; In the above formula, a represents the scanning aperture in the x direction, b represents the scanning aperture in the y direction, kx represents the wave number component in the x direction, and ky represents the wave number component in the y direction. represents the plane wave spectrum component in the x direction at z=0, Represents the plane wave spectrum component in the y direction at z=0.

[0067] According to the relationship between the plane wave spectrum and the antenna far-field pattern, the antenna far-field can be expressed as: ; ; ; The polarization characteristics of the composite wave depend on the amplitudes of the orthogonal linear polarization components and their phase difference.

[0068] The sum of the energies radiated from the antenna under test to the far field at a certain distance r0 (r0 is much larger than the aperture of the antenna under test) is: .

[0069] Using the known gain The standard linear polarization antenna is used as the reference antenna. The near field scanning of the reference antenna is performed under the same test platform, phased test conditions, sampling interval and sampling step. The far field energy radiated from the reference antenna to the far field at a certain distance r is obtained as follows: .

[0070] Then the gain of the antenna under test is: ; Thus, the gain of the antenna under test can be obtained.

[0071] When measuring the antenna near field, define Corresponding to the horizontal polarization direction, Corresponding to the vertical polarization direction, the wave is transmitted toward the probe direction. yes Ahead of the times The phase angle of When it is positive, the antenna under test is left-handed. When it is a negative value, the antenna under test is right-handed. is the inclination angle of the polarization ellipse of the antenna under test, It can be expressed as: ; The axial ratio of the antenna under test can be expressed as: ; The polarization direction and axial ratio of the antenna can be determined from the above relationship.

[0072] Two specific implementation examples are provided below.

[0073] Example 1 In order to determine the horn antenna (such as Figure 6 The normal gain and polarization characteristics of the Figure 1 The device shown was tested by the method provided in this example.

[0074] The process is as follows: a1. Power on the test device and run the relevant test software; b1. Install the antenna under test firmly on the test platform in the microwave dark box, connect the RF port of the antenna under test to the first port of the vector network instrument, and connect the test probe to the second port of the vector network instrument; c1. Adjust the test platform and the height of the test probe so that the test probe is 110 mm away from the antenna under test, and move the test probe horizontally to the center position just above the antenna under test, and set this position as the origin; then move the test probe along a predetermined trajectory, which can be a plane movement trajectory, a cylindrical movement trajectory, or a spherical movement trajectory; d1. According to the tested frequency of the antenna under test, 8.2 GHz, the type of antenna under test (the antenna is a directional antenna) and the gain (the gain is initially judged to be greater than 10 dB), set the appropriate near-field scanning distance of 4 mm and the number of scanning points to 201; e1. Set the vector network frequency to 8.2GHz and the output power to 0dBm; f1. Perform near-field scanning and complete the near-field scanning to obtain the complex signal of each scanning point ; g1. Return to the probe origin, rotate the probe 90°, reset it to the probe origin, complete the near-field scan, and obtain the complex signal ; h1. Use the test software to calculate the axial ratio and obtain the axial ratio of the antenna under test.

[0075] Figure 7 This is a comparison of the full-wave simulation of the horn antenna and the directional pattern calculated using the method of the present invention (Phi=0deg). Figure 7 As shown, it can be seen that the full-wave simulation pattern result and the near-field and far-field transformation pattern using the method of the present invention have a high consistency, indicating that the method of the present invention can be used to perform pattern testing.

[0076] FIG8 is a comparison of the full-wave simulation of the horn antenna and the directional pattern calculated using the method of the present invention (Phi=90deg). Figure 8 As shown, it can be seen that the full-wave simulation pattern result and the near-field and far-field transformation pattern using the method of the present invention have a high consistency, indicating that the pattern test can be performed using the method of the present invention.

[0077] FIG9 is a diagram showing the aperture field distribution of a horn antenna calculated using the method of the present invention. Fig. 9 As shown, it can be seen that the method of the present invention can directly obtain the X and Y components of the electric field and phase of the antenna under test, and the components can be used for diagnosis and analysis of the radiation performance of unit antennas and phased array antennas.

[0078] FIG10 is a diagram showing the three-dimensional axial ratio distribution of a horn antenna calculated using the method of the present invention. Fig.10 As shown, it can be seen that the three-dimensional axial ratio distribution of the current state of the antenna under test can be directly obtained by using the method of the present invention.

[0079] FIG11 is a diagram showing the two-dimensional axial ratio distribution (phi=0deg, 90deg) of a horn antenna calculated using the method of the present invention. Fig.11 As shown, it can be seen that the two-dimensional main section axial ratio pattern of the antenna under test can be directly obtained by the method of the present invention. The normal axial ratio of the antenna under test is about 64 dB. It can be determined that the antenna is a linearly polarized antenna with good linear polarization characteristics.

[0080] The test software constructed by the method of the present invention can directly calculate the gain, polarization and normal axis ratio of the antenna under test after completing the near field scan of the antenna under test. From the calculation results, the gain of the antenna under test is 17.05dBi, the polarization mode is linear polarization, and the normal axis ratio is 63.6dB.

[0081] Example 2 In order to determine the dielectric filled horn antenna (such as Fig.12 The normal gain and polarization characteristics of the Figure 1 The device shown was tested by the method provided in this example.

[0082] The process is as follows: a2. Power on the test device and run the relevant test software; b2. The antenna to be tested is stably mounted on the test platform in the microwave dark box, the RF port of the antenna to be tested is connected to the first port of the vector network instrument, and the test probe is connected to the second port of the vector network instrument; c2. Adjust the test platform and the test probe height so that the test probe is 110 mm away from the antenna under test, and move the test probe horizontally to the center position just above the antenna under test, and set this position as the origin; then move the test probe along a predetermined trajectory, which can be a plane movement trajectory, a cylindrical movement trajectory, or a spherical movement trajectory; d2. According to the tested frequency of the antenna under test, 8.2 GHz, the type of antenna under test (the antenna is a directional antenna) and the gain (the gain is initially judged to be greater than 8 dB), set the appropriate near-field scanning distance of 4 mm and the number of scanning points to 201; e2. Set the vector network frequency to 8.2GHz and the output power to 0dBm; f2. Perform near-field scanning and complete the near-field scanning to obtain the complex signal of each scanning point ; g2. Return to the probe origin, rotate the probe 90°, reset it to the probe origin, complete the near-field scan, and obtain the complex signal ; h2. Use the test software to calculate the axial ratio and obtain the axial ratio of the antenna under test.

[0083] Fig.13 The method of the present invention is used to calculate the directivity pattern (Phi=0deg, 90deg) of the dielectric-filled horn antenna.

[0084] Fig.14 The method of the present invention is used to calculate the aperture field distribution for dielectric-filled horn antennas. It can be seen that the method of the present invention can directly obtain the aperture electric field and the X and Y components of the phase of the measured antenna, which can be used for the diagnosis and analysis of the radiation performance of unit antennas and phased array antennas.

[0085] Fig.15 The three-dimensional axial ratio distribution of the dielectric-filled horn antenna is calculated using the method of the present invention. It can be seen that the three-dimensional axial ratio distribution of the current state of the antenna under test can be directly obtained using the method of the present invention.

[0086] Fig.16 The two-dimensional axial ratio distribution (phi=0deg, 90deg) of the dielectric-filled horn antenna is calculated using the method of the present invention. It can be seen that the two-dimensional main section axial ratio pattern of the antenna under test can be directly obtained using the method of the present invention. The normal axial ratio of the antenna under test is about 0.6dB, and it can be determined that the antenna is a circularly polarized antenna with good circular polarization characteristics.

[0087] The test software constructed by the method of the present invention can directly calculate the gain, polarization and normal axis ratio of the antenna under test after completing the near field scan of the antenna under test. From the calculation results, the gain of the antenna under test is 10.38dBi, the polarization mode is right-hand circular polarization, and the normal axis ratio is 0.59dB.

[0088] The technical solution of this application has the following differences and advantages over the existing antenna gain and polarization test methods: (1) Existing antenna gain and polarization test methods usually require the use of a far-field test environment. When the aperture of the antenna under test is large and the operating wavelength is short, a longer test distance is required, which places higher requirements on the test site of the antenna under test. Whether using a far-field microwave darkroom or a compact field darkroom, there are high costs and large space limitations for large-aperture antenna test sites. However, using the method of the present invention, it is only necessary to scan the near field of the antenna under test in a smaller space, and then use Fourier transform to obtain the far field of the antenna under test. Finally, the antenna polarization characteristics, axial ratio and polarization rotation are determined by the electric field components of the two polarization components.

[0089] (2) Using the traditional antenna testing method, it is necessary to test the gain, radiation pattern, axial ratio, and rotation direction separately in the far-field environment. Each item needs to be tested separately, and the testing process is complicated, time-consuming and labor-intensive. Using the method of the present invention, it is only necessary to scan the near field of the antenna under test in a small space, and then use Fourier transform to obtain the far field of the antenna under test. According to the far field, the antenna gain, radiation pattern, axial ratio, and rotation direction can be directly, quickly and efficiently obtained.

[0090] Those skilled in the art will readily appreciate other embodiments of the present application after considering the specification and practicing the embodiments disclosed herein. The present application is intended to cover any variations, uses or adaptations of the present application, which follow the general principles of the present application and include common knowledge or customary techniques in the art that are not disclosed in the present application. It should be understood that the present application is not limited to the precise structures described above and shown in the accompanying drawings, and various modifications and changes can be made without departing from the scope thereof. The scope of the present application is limited only by the appended claims.

Claims

1. A device for testing antenna gain and polarization, characterized in that: include: Measuring units, microwave darkrooms, test probes and control components; The measuring unit is connected to the test probe and is used to output a radio frequency signal to the test probe; The test probe and the antenna under test are placed in the microwave dark box, and the test probe is close to the antenna under test, wherein the test probe is used to convert the radio frequency signal output by the measuring unit into an electromagnetic signal for radiation, and the antenna under test receives the electromagnetic signal and converts it into a radio frequency signal for transmission to the measuring unit; The control component is connected to the test probe and is used to control the test probe to move near the antenna under test along a predetermined trajectory.

2. The device according to claim 1, characterized in that The control component includes: a manipulator controller and a first intelligent terminal; The first intelligent terminal is connected to the manipulator controller and is used to control the manipulator controller to move according to a predetermined trajectory; The manipulator controller is connected to the test probe and is used to drive the test probe to move along a predetermined trajectory.

3. The device according to claim 1, characterized in that The measuring unit includes a vector network instrument and a second intelligent terminal; The second intelligent terminal is connected to the vector network instrument to control the vector network instrument to perform radio frequency signal sampling; The vector network instrument is also connected to the test probe and the antenna under test respectively, and is used to output radio frequency signals to the test probe and receive radio frequency signals transmitted from the antenna under test.

4. The device according to claim 1, characterized in that The predetermined trajectory includes a plane movement trajectory, a cylindrical movement trajectory and a spherical movement trajectory; The plane moving track refers to the test probe moving at a fixed distance above the antenna under test at uniform intervals. and The trajectory formed by the movement, where , , Indicates wavelength; The cylindrical surface movement trajectory refers to the test probe wrapping the cylindrical surface of the antenna under test according to the azimuth angle. , Towards The trajectory formed by evenly spaced movements, where , , is the beam constant, is the radius of the scanning cylinder; The spherical movement trajectory refers to the test probe wrapping the spherical surface of the antenna under test at a rotation angle interval , off-axis angle The trajectory formed by evenly spaced movements, where , , , is the number of modes of the spherical wave expansion, is the radius of the smallest sphere that encloses the antenna under test.

5. The device according to claim 1, characterized in that Also includes: Power module; The power supply module is connected to the measuring unit and the control component respectively.

6. A method for testing antenna gain and polarization, applied to the device as claimed in any one of claims 1 to 5, characterized in that: include: Placing the antenna under test in a microwave dark box, connecting the measuring unit to the test probe, and connecting the control component to the test probe; Adjust the distance between the test probe and the antenna under test, and move the test probe to the center position just above the antenna under test, record it as the origin, and then move the test probe along the predetermined trajectory; Set the test parameters according to the test frequency, antenna type and gain of the antenna under test; Perform a near-field scan and calculate the gain, polarization rotation and axial ratio of the antenna under test based on the scan results.

7. The method according to claim 6, characterized in that The step of moving the test probe along a predetermined trajectory includes: The test probe is moved along a plane moving track, a cylindrical moving track or a spherical moving track.

8. The method according to claim 6, characterized in that The test parameters include: near field scanning distance, number of scanning points, vector network frequency and output power.

9. The method according to claim 6, characterized in that The near-field scanning comprises: When the test probe is at the current position, a first near-field scan is performed to obtain a first complex signal at each scanning point; Return the test probe to the origin and rotate it by a preset angle to perform a second approach scan to obtain a second complex signal at each scan point.

10. The method according to claim 9, characterized in that The step of calculating the gain, polarization rotation direction and axial ratio of the antenna under test based on the scanning result includes: Determine a plane wave spectrum corresponding to the electric field according to the first complex signal of each scanning point and the second complex signal of each scanning point; Determine the antenna far field based on the relationship between the plane wave spectrum and the antenna far field pattern; The gain, polarization rotation direction and axial ratio of the antenna under test are calculated based on the antenna far field.

Images