A device and method for testing antenna gain and polarization

Abstract

The embodiment of the present application provides a device and method for testing antenna gain and polarization, which relates to the field of antenna testing technology, and the device includes: 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 and transmits it 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. The technical solution of the present application solves the high cost and large space limitations of large-caliber antenna test sites, and the test method is simple, and has high application value.

Description

Technical Field

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

[0002] Currently, there are two common 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's formula, identical antenna method), the three-antenna method (solving three unknowns using three equations), and the mirror image method (using a flat metal reflector). However, to confirm the gain of the antenna being measured, both comparative and absolute methods are typically limited to far-field environments.

[0005] In addition to antenna gain, antenna polarization is also an important performance indicator. There are three types of antenna polarization: linear, circular, and elliptical. The axial ratio can generally be used to determine the polarization characteristics of an antenna. When the axial ratio is ≤7dB, the antenna under test is considered circularly polarized, while when the axial ratio is greater than 7dB, it is considered linearly polarized. To determine whether the antenna under test is linearly or circularly polarized, and to determine the axial ratio of a circularly polarized antenna, it is also necessary to perform the test in a far-field environment.

[0006] Commonly used antenna gain and antenna polarization tests place high demands on the test site, especially when the antenna being tested has a large aperture. Whether it is a standard far-field chamber or a compact far-field chamber, the construction cost is high. 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 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 darkroom, a test probe, and a control component;

[0010] The measuring unit is connected to the test probe and is used to output a radio frequency signal to the test probe;

[0011] The test probe and the antenna under test are placed in the microwave darkroom, with the test probe 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 and transmits it to the measuring unit;

[0012] 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.

[0013] In some embodiments of the present application, based on the aforementioned solution, the control component includes: a manipulator controller and a first intelligent terminal;

[0014] The first intelligent terminal is connected to the manipulator controller and is used to control the manipulator controller to move along a predetermined trajectory;

[0015] The manipulator controller is connected to the test probe and is used to drive the test probe to move along a predetermined trajectory.

[0016] In some embodiments of the present application, based on the aforementioned solution, the measurement unit includes a vector network instrument and a second intelligent terminal;

[0017] The second intelligent terminal is connected to the VNS instrument and controls the VNS instrument to perform radio frequency signal sampling;

[0018] 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.

[0019] In some embodiments of the present application, based on the aforementioned solution, the predetermined trajectory includes a planar movement trajectory, a cylindrical movement trajectory, and a spherical movement trajectory;

[0020] The plane moving track refers to the test probe being at a fixed distance above the antenna under test, at even intervals. and The trajectory formed by movement, where , , Indicates wavelength;

[0021] 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;

[0022] The spherical movement trajectory refers to the test probe wrapping the spherical surface of the antenna under test according to the rotation angle interval , off-axis angle The trajectory formed by evenly spaced movements, where , , , is the mode number of the spherical wave expansion, is the radius of the smallest sphere that encloses the antenna under test.

[0023] In some embodiments of the present application, based on the aforementioned solution, the present invention further includes: a power supply module;

[0024] The power supply module is connected to the measuring unit and the control component respectively.

[0025] 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 apparatus according to the first aspect, including:

[0026] 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;

[0027] Adjust the distance between the test probe and the antenna under test, and move the test probe to the center position directly above the antenna under test, marking it as the origin, and then move the test probe along the predetermined trajectory;

[0028] Set the test parameters according to the test frequency, antenna type and gain of the antenna under test;

[0029] Perform a near-field scan and calculate the gain, polarization rotation, and axial ratio of the antenna under test based on the scan results.

[0030] In some embodiments of the present application, based on the above solution, moving the test probe along a predetermined trajectory includes:

[0031] Move the test probe along a plane movement trajectory, a cylindrical movement trajectory, or a spherical movement trajectory.

[0032] In some embodiments of the present application, based on the aforementioned solution, the test parameters include: near-field scanning distance, number of scanning points, vector network frequency and output power.

[0033] In some embodiments of the present application, based on the aforementioned solution, performing near-field scanning includes:

[0034] When the test probe is at the current position, performing a first near-field scan to obtain a first complex signal at each scan point;

[0035] 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.

[0036] In some embodiments of the present application, based on the aforementioned solution, the step of calculating the gain, polarization rotation, and axial ratio of the antenna under test based on the scanning results includes:

[0037] determining 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;

[0038] Determine the antenna far field based on the relationship between the plane wave spectrum and the antenna far field pattern;

[0039] The gain, polarization rotation direction and axial ratio of the antenna under test are calculated based on the antenna far field.

[0040] 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. According to the far field, the antenna gain, radiation pattern, axial ratio, and rotation direction can be directly, quickly and efficiently obtained, which solves the high cost and large space limitations of large-aperture antenna test sites. The test method is simple and has high application value.

[0041] 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

[0042] The accompanying drawings are incorporated into and constitute a part of the specification, illustrating embodiments consistent with the present application and, together with the specification, explaining the principles of the present application. Obviously, the drawings described below are only some embodiments of the present application, and those skilled in the art can derive other drawings based on these drawings without inventive effort. In the drawings:

[0043] Figure 1 A schematic structural diagram of a device for testing antenna gain and polarization according to an embodiment of the present application is shown;

[0044] Figure 2 A schematic diagram of a near-field plane scanning node according to an embodiment of the present application is shown;

[0045] Figure 3 A schematic diagram of a near-field cylindrical scanning node according to an embodiment of the present application is shown;

[0046] Figure 4 A schematic diagram of a near-field spherical scanning node according to an embodiment of the present application is shown;

[0047] Figure 5A schematic diagram of planar near-field scanning according to an embodiment of the present application is shown;

[0048] Figure 6 A schematic diagram of a horn antenna according to an embodiment of the present application is shown;

[0049] Figure 7 A schematic diagram comparing full-wave simulation of a horn antenna according to an embodiment of the present application and directivity patterns calculated using the method of the present invention is shown (Phi=0deg);

[0050] Figure 8 A schematic diagram comparing the full-wave simulation of a horn antenna according to one embodiment of the present application and the directional pattern calculated using the method of the present invention (Phi=90deg) is shown;

[0051] Figure 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;

[0052] Figure 10 A schematic diagram of calculating the three-dimensional axial ratio distribution of a horn antenna using the method of the present invention according to one embodiment of the present application is shown;

[0053] Figure 11 A schematic diagram of calculating the two-dimensional axial ratio distribution of a horn antenna using the method of the present invention according to an embodiment of the present application (phi=0deg, 90deg) is shown;

[0054] Figure 12 A schematic diagram of a dielectric-filled horn antenna according to an embodiment of the present application is shown;

[0055] Figure 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);

[0056] Figure 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;

[0057] Figure 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;

[0058] Figure 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.

[0059] Description of Reference Numerals

[0060] 1-VGA, 2-test probe, 3-tested antenna, 4-microwave darkroom, 5-manipulator controller, 6-computer, 7-power module. DETAILED DESCRIPTION

[0061] Example embodiments will now be described more fully with reference to the accompanying drawings. However, example embodiments can be implemented in many 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 thorough and complete and will fully convey the concepts of the example embodiments to those skilled in the art.

[0062] 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 so as to provide a full understanding of the embodiments of the present application. However, it will be appreciated by those skilled in the art 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, implementations or operations are not shown or described in detail to avoid blurring the various aspects of the application.

[0063] The block diagrams shown in the accompanying drawings are merely functional entities and do not necessarily correspond to physically separate entities. That is, these functional entities may be implemented in software, in one or more hardware modules or integrated circuits, or in different networks and / or processor devices and / or microcontroller devices.

[0064] The flowcharts shown in the accompanying drawings are for illustrative purposes only and do not necessarily include all contents and operations / steps, nor must they be executed in the order described. For example, some operations / steps may be decomposed, while others may be combined or partially combined. Therefore, the actual execution order may vary depending on the actual situation.

[0065] It should be noted that the terms "first," "second," and the like in the specification and claims of this application and the accompanying drawings are used to distinguish similar objects and are not necessarily used to describe a specific order or precedence. It should be understood that the terms used in this manner are interchangeable where appropriate, such that the embodiments of the present application described herein can be implemented in an order other than that illustrated or described.

[0066] To make the objectives, technical solutions, and advantages of the present invention more clear, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts shall fall within the scope of protection of the present invention.

[0067] The following will describe some embodiments of the present application in detail with reference to the accompanying drawings. In the absence of conflict, the following embodiments and features therein may be combined with each other.

[0068] 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;

[0069] The measuring unit is connected to the test probe and is used to output a radio frequency signal to the test probe;

[0070] The test probe and the antenna under test are placed in the microwave darkroom, with the test probe 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 and transmits it to the measuring unit;

[0071] 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.

[0072] 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.

[0073] 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.

[0074] It should be noted that during the operation of this 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.

[0075] In some feasible embodiments, based on the aforementioned solution, the control component includes: a manipulator controller and a first intelligent terminal;

[0076] The first intelligent terminal is connected to the manipulator controller and is used to control the manipulator controller to move along a predetermined trajectory;

[0077] The manipulator controller is connected to the test probe and is used to drive the test probe to move along a predetermined trajectory.

[0078] 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.

[0079] In some feasible embodiments, based on the above solution, the measuring unit includes a vector network instrument and a second intelligent terminal;

[0080] The second intelligent terminal is connected to the VNS instrument and controls the VNS instrument to perform radio frequency signal sampling;

[0081] 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.

[0082] It should be noted that, in order to save costs, the first smart terminal and the second smart terminal can use the same computer, which can control the manipulator controller to move along a predetermined trajectory and also control the vector network instrument to sample radio frequency signals.

[0083] For example, see Figure 1 , shows a structural schematic diagram of a device for testing antenna gain and polarization according to an embodiment of the present application.

[0084] 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.

[0085] The antenna under test 3 and the test probe 2 are placed in a microwave darkroom 4, and the test probe 2 is directly above the antenna under test 3 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. 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.

[0086] 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.

[0087] 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.

[0088] It should be noted that, in this example, the test probe is a linearly polarized antenna.

[0089] In some feasible embodiments, based on the above solution, the predetermined trajectory includes a planar movement trajectory, a cylindrical movement trajectory, and a spherical movement trajectory;

[0090] The plane moving track refers to the test probe being at a fixed distance above the antenna under test, at even intervals. and The trajectory formed by movement, where , , Indicates wavelength;

[0091] 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;

[0092] The spherical movement trajectory refers to the test probe wrapping the spherical surface of the antenna under test according to the rotation angle interval , off-axis angle The trajectory formed by evenly spaced movements, where , , , is the mode number of the spherical wave expansion, is the radius of the smallest sphere that encloses the antenna under test.

[0093] It should be noted that the use of a plane, a cylindrical surface, or a spherical surface movement trajectory can achieve scanning of the antenna under test on the plane, the cylindrical surface, or the spherical surface, so that the acquired signal is more complete.

[0094] 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.

[0095] 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.

[0096] 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 a test probe to extract the near field of the antenna under test.

[0097] See also Figure 5 , shows a schematic diagram of planar near-field scanning according to an embodiment of the present application.

[0098] 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 even intervals and ( , ) moves, and the moving process is as follows Figure 5 shown.

[0099] 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 radius of the scanning cylinder).

[0100] 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 mode number of the spherical wave expansion, is the radius of the smallest sphere that surrounds the antenna under test).

[0101] In some feasible embodiments, based on the above solution, the device further includes: a power supply module;

[0102] The power supply module is connected to the measuring unit and the control component respectively.

[0103] For example, Figure 1The 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 provide 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.

[0104] 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 apparatus described in any of the above embodiments, and the method includes:

[0105] Step S100: 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;

[0106] Step S200: Adjust the distance between the test probe and the antenna under test, and move the test probe to the center position directly above the antenna under test, which is recorded as the origin. Then, move the test probe along a predetermined trajectory.

[0107] Step S300, setting test parameters according to the test frequency, antenna type and gain of the antenna under test;

[0108] Step S400: Perform a near-field scan and calculate the gain, polarization rotation, and axial ratio of the antenna under test based on the scan results.

[0109] In some feasible embodiments, based on the above solution, moving the test probe along a predetermined trajectory includes:

[0110] Move the test probe along a plane movement trajectory, a cylindrical movement trajectory, or a spherical movement trajectory.

[0111] It is understandable that moving the test probe along different movement trajectories can achieve scanning of different surfaces of the antenna under test.

[0112] In some feasible embodiments, based on the aforementioned solution, the test parameters include: near-field scanning distance, number of scanning points, vector network frequency and output power.

[0113] In some feasible embodiments, based on the above solution, performing near-field scanning includes:

[0114] When the test probe is at the current position, performing a first near-field scan to obtain a first complex signal at each scan point;

[0115] 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.

[0116] It should be noted that the current position mentioned in this embodiment refers to the position of the test probe after it has moved.

[0117] In some feasible embodiments, based on the above solution, calculating the gain, polarization rotation direction, and axial ratio of the antenna under test based on the scanning results includes:

[0118] determining 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;

[0119] Determine the antenna far field based on the relationship between the plane wave spectrum and the antenna far field pattern;

[0120] The gain, polarization rotation direction and axial ratio of the antenna under test are calculated based on the antenna far field.

[0121] A specific example of this method is provided below.

[0122] (a) Power on the test device and run the relevant test software;

[0123] (b) The antenna under test is firmly mounted on the test platform in the microwave darkroom. The RF port of the antenna under test is connected to the first port of the VNS instrument, and the test probe is connected to the second port of the VNS instrument.

[0124] (c) Adjust the test platform and test probe height so that the test probe is 3-5 wavelengths away from the antenna under test. Move the test probe horizontally to the center position directly above the antenna under test, setting this position as the origin. Then move the test probe along a predetermined trajectory, which can be a planar trajectory, a cylindrical trajectory, or a spherical trajectory.

[0125] (d) Set the appropriate near-field scan spacing and number of scan points based on the test frequency, antenna type, and gain of the antenna under test;

[0126] (e) Setting the VN frequency and output power;

[0127] (f) Perform near-field scanning and complete the near-field scanning to obtain the complex signal at each scanning point ;

[0128] (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 ;

[0129] (h) Use the test software to calculate the axial ratio and obtain the axial ratio of the antenna under test.

[0130] Reconstruct the signal based on two calibration scan points and , we can directly obtain the plane wave spectrum corresponding to the electric field: .

[0131] The plane wave spectrum and the corresponding electric field have the following relationship:

[0132] ;

[0133] In the above formula,

[0134] ;

[0135] ;

[0136] ;

[0137] In the above formula, Represents the position vector from the spatial source point to the field point.

[0138] According to the relationship between plane wave spectrum and electric field, the electric field components of the x and y surfaces at plane Z=0 are obtained as follows:

[0139] ;

[0140] ;

[0141] ;

[0142] ;

[0143] 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 x-direction plane wave spectrum component at z=0, Represents the plane wave spectrum component in the y direction at z=0.

[0144] According to the relationship between the plane wave spectrum and the antenna far-field pattern, the antenna far-field can be expressed as:

[0145] ;

[0146] ;

[0147] ;

[0148] The polarization characteristics of the composite wave depend on the amplitudes of the orthogonal linear polarization components and their phase difference.

[0149] The sum of the energies radiated from the antenna under test to the far-field determined distance r0 (r0 is much larger than the aperture of the antenna under test) is:

[0150] .

[0151] Using the known gain The standard linearly polarized antenna is used as the reference antenna. The near-field scan 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 is obtained as follows: .

[0152] Then the gain of the antenna under test is:

[0153] ;

[0154] This can be used to obtain the gain of the antenna under test.

[0155] 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 The phase angle of When it is a positive value, 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:

[0156] ;

[0157] The axial ratio of the antenna under test can be expressed as:

[0158] ;

[0159] The above relationship can be used to determine the polarization direction and axial ratio of the antenna.

[0160] Two specific implementation examples are provided below.

[0161] Example 1

[0162] In order to determine the Figure 6 The normal gain and polarization characteristics of the CMOS are shown in Figure 2. Figure 1 The device shown was tested by the method provided in this example.

[0163] The process is as follows:

[0164] a1. Power on the test device and run the relevant test software;

[0165] 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 VNS instrument and the test probe to the second port of the VNS instrument.

[0166] c1. Adjust the test platform and test probe height so that the test probe is 110 mm away from the antenna under test. Move the test probe horizontally to the center position directly 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 planar trajectory, a cylindrical trajectory, or a spherical trajectory.

[0167] d1. Based on the test frequency of 8.2 GHz, the type of antenna (directional) and the gain (preliminary gain estimation is greater than 10 dB), set the appropriate near-field scanning distance to 4 mm and the number of scanning points to 201.

[0168] e1. Set the vector network frequency to 8.2GHz and the output power to 0dBm;

[0169] f1. Perform near-field scanning and complete the near-field scanning to obtain the complex signal at each scanning point ;

[0170] 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 ;

[0171] h1. Use the test software to calculate the axial ratio and obtain the axial ratio of the antenna under test.

[0172] Figure 7 The figure shows the comparison between 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 pattern test can be performed using the method of the present invention.

[0173] Figure 8 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.

[0174] Figure 9 shows the calculation of the aperture field distribution of the horn antenna using the method of the present invention. Figure 9 As shown, it can be seen that the method of the present invention can directly obtain the electric field and X and Y components of the phase of the antenna under test, which can be used for diagnosis and analysis of the radiation performance of unit antennas and phased array antennas.

[0175] Figure 10 shows the three-dimensional axial ratio distribution of the horn antenna calculated using the method of the present invention. Figure 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.

[0176] Figure 11 shows the two-dimensional axial ratio distribution (phi = 0deg, 90deg) of the horn antenna calculated using the method of the present invention. Figure 11 As shown, it can be seen that the two-dimensional main cross-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.

[0177] The test software constructed using the method described in this invention can directly calculate the antenna's gain, polarization, and normal-to-axis ratio after completing a near-field scan of the antenna under test. The calculated results show that the antenna's gain is 17.05 dBi, its polarization is linear, and its normal-to-axis ratio is 63.6 dB.

[0178] Example 2

[0179] In order to determine the dielectric filled horn antenna (such as Figure 12 The normal gain and polarization characteristics of the CMOS are shown in Figure 2. Figure 1 The device shown was tested by the method provided in this example.

[0180] The process is as follows:

[0181] a2. Power on the test device and run the relevant test software;

[0182] b2. 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 VNS, and connect the test probe to the second port of the VNS;

[0183] c2. Adjust the test platform and test probe height so that the test probe is 110 mm away from the antenna under test. Move the test probe horizontally to the center position directly 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 planar trajectory, a cylindrical trajectory, or a spherical trajectory.

[0184] d2. Based on the test frequency of 8.2 GHz, the type of antenna (directional) and the gain (preliminary gain estimation is greater than 8 dB), set the appropriate near-field scan spacing to 4 mm and the number of scan points to 201.

[0185] e2. Set the vector network frequency to 8.2GHz and the output power to 0dBm;

[0186] f2. Perform near-field scanning and complete the near-field scanning to obtain the complex signal of each scanning point ;

[0187] 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. ;

[0188] h2. Use the test software to calculate the axial ratio and obtain the axial ratio of the antenna under test.

[0189] Figure 13 The method of the present invention is used to calculate the directivity pattern (Phi=0deg, 90deg) of a dielectric-filled horn antenna.

[0190] Figure 14 The method of the present invention is used to calculate the aperture field distribution for a dielectric-filled horn antenna. It can be seen that the method of the present invention can directly obtain the calculated aperture electric field and phase X and Y components of the measured antenna. These components can be used to diagnose and analyze the radiation performance of unit antennas and phased array antennas.

[0191] Figure 15 The three-dimensional axial ratio distribution of a 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.

[0192] Figure 16 The method of the present invention was used to calculate the two-dimensional axial ratio distribution (phi = 0deg, 90deg) for a dielectric-filled horn antenna. It can be seen that the method of the present invention can directly obtain the two-dimensional main cross-sectional axial ratio pattern of the antenna under test. The normal axial ratio of the antenna under test is approximately 0.6dB, indicating that the antenna is a circularly polarized antenna with good circular polarization characteristics.

[0193] The test software constructed using the method described in this invention can directly calculate the antenna's gain, polarization, and normal-axis ratio after completing a near-field scan of the antenna under test. The calculated results show that the antenna's gain is 10.38dBi, its polarization is right-hand circular polarization, and its normal-axis ratio is 0.59dB.

[0194] The technical solution of this application has the following differences and advantages over existing antenna gain and polarization testing methods:

[0195] (1) Existing antenna gain and polarization test methods usually require the use of a far-field test environment. When the antenna under test has a large aperture and a short operating wavelength, a longer test distance is required, which places higher demands on the test site for the antenna under test. Whether using a far-field microwave anechoic chamber or a compact field anechoic chamber, 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.

[0196] (2) Using traditional antenna testing methods, it is necessary to test the gain, radiation pattern, axial ratio, and rotation direction separately in a far-field environment. Each item needs to be tested separately, which 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. Based on the far field, the antenna gain, radiation pattern, axial ratio, and rotation direction can be directly and efficiently obtained.

[0197] Those skilled in the art will readily appreciate other embodiments of the present application after considering the specification and practicing the embodiments disclosed herein. This application is intended to cover any variations, uses, or adaptations of the present application that follow the general principles of the present application and include common knowledge or customary techniques in the art that are not disclosed in this application. It should be understood that this 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 this application is limited only by the appended claims.

Claims

1. A method for testing antenna gain and polarization, 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 near-field scanning and calculate the gain, polarization rotation direction and axial ratio of the antenna under test based on the scanning results; 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; 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.

2. The method according to claim 1, 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.

3. The method according to claim 1, characterized in that The test parameters include: near field scanning distance, number of scanning points, vector network frequency and output power.

4. A device applied to the method according to any one of claims 1 to 3, 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.

5. The device according to claim 4, 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.

6. The device according to claim 4, 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.

7. The device according to claim 4, 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.

8. The device according to claim 4, characterized in that Also includes: Power module; The power supply module is connected to the measuring unit and the control component respectively.

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