A method for drawing antenna patterns under full-size target conditions

Abstract

This invention relates to a method for drawing antenna radiation patterns under full-size target conditions, relating to the field of testing, and includes the following steps: adjusting the center of gravity of the full-size target to the center point of the quiet zone relative to the rotation axis of the turntable; calculating the distance between the aperture of the antenna under test and the center point of the quiet zone based on the center of gravity of the full-size target and the aperture position of the antenna under test; adjusting the support frame to make the center height of the antenna under test the same as the center point height of the quiet zone; setting the polarization of the transmitting antenna and connecting the transmitting link; setting the polarization and installation angle of the antenna under test and connecting the receiving link; computer-controlled turntable rotating from a -180° azimuth of the full-size target to +180° in a top-down counterclockwise direction, transmitting the angle signal to a spectrum analyzer or computer during the rotation; and drawing the antenna radiation pattern of the full-size target based on the test and calculation results. This invention has the advantage of being able to quickly and easily obtain the antenna radiation pattern of the antenna under full-size target conditions.

Description

Technical Field

[0001] This invention relates to the field of testing technology, and in particular to a method for drawing antenna patterns under full-size target conditions. Background Technology

[0002] Antennas are typically used in far-field conditions, so to accurately test their radiation characteristics, a test field is essential to provide uniform planar electromagnetic wave illumination. Test fields are mainly categorized as outdoor or indoor. In practical applications, due to the influence of direct or reflected waves in outdoor fields, the minimum test distance formula... It is difficult to achieve full-band coverage in the far field, so it is usually tested in a microwave anechoic chamber with a compact field that can better simulate free space. It has advantages such as all-weather operation, wide bandwidth, good shielding performance, and security.

[0003] In general, antenna pattern testing is conducted in a microwave anechoic chamber. However, many antennas are often installed on various target carriers, such as satellites and other carriers that rely on radar antennas to transmit and receive signals. The accuracy of their antenna pattern is crucial, especially the accuracy of the antenna pattern under full-size target conditions after installation. The antenna may be affected by installation tolerances, obstruction by the target shape after installation, internal losses of cables and connectors after installation, and the influence of other antennas along the cavity or metal surface. This can affect the amplitude or directivity of the antenna's main lobe and side lobes, thus greatly affecting the antenna's performance.

[0004] Therefore, to address the above shortcomings, a method for drawing antenna radiation patterns under full-size target conditions is needed. Summary of the Invention

[0005] (a) Technical problems to be solved

[0006] The technical problem to be solved by this invention is to address the issue that, in the past, antennas could only be measured and their radiation patterns obtained individually, which led to abnormal signal transmission and reception of full-size targets after the antenna was installed in the working state.

[0007] (II) Technical Solution

[0008] To address the aforementioned technical problems, this invention provides a method for drawing antenna radiation patterns under full-size target conditions, comprising the following steps:

[0009] I. Determine the dimensions of the quiet zone in the microwave anechoic chamber, the full-size target, the center point of the quiet zone, and the center of gravity of the full-size target, and confirm that the aperture of the antenna under test is located on the full-size target;

[0010] II. Adjust the center of gravity of the full-size target to the center point of the quiet zone relative to the rotation axis of the turntable; calculate the distance between the aperture of the antenna under test and the center point of the quiet zone based on the center of gravity of the full-size target and the aperture position of the antenna under test;

[0011] III. Place the full-size target on the support frame in its working state, and adjust the height of the support frame so that the center height of the antenna under test is the same as the center point height of the quiet zone;

[0012] IV. Set the polarization of the transmitting antenna according to the test requirements and connect the transmitting link; set the polarization and installation angle of the antenna under test and connect the receiving link;

[0013] V. The computer-controlled turntable performs one-dimensional planar rotation, rotating from a -180° position of the full-size target to +180° in a top-down counterclockwise direction. During the rotation, the turntable transmits the angle signal to a spectrum analyzer or computer to calculate the receiver input level.

[0014] VI. Based on the test and calculation results, draw the antenna pattern of the full-size target and obtain the differences in installing the full-size target by comparing it with the individual antenna patterns.

[0015] As a further explanation of the present invention, preferably, if the distance between the aperture of the antenna under test and the center point of the quiet zone is less than the size of the quiet zone, then the antenna under test will always be within the quiet zone during rotation.

[0016] As a further explanation of the present invention, preferably, the transmitting link includes a signal source, a power amplifier, and a transmitting antenna, wherein the signal source is electrically connected to the power amplifier, and the power amplifier is electrically connected to the transmitting antenna.

[0017] As a further explanation of the present invention, preferably, the receiving end link includes an antenna under test, a spectrum analyzer, and a turntable. The antenna under test is electrically connected to the spectrum analyzer, and the spectrum analyzer is electrically connected to the turntable or electrically connected to the turntable via a computer.

[0018] As a further explanation of the present invention, preferably, the receiver input level satisfies:

[0019] P r =P AUT -I A

[0020] in,

[0021] P r This is the receiver input level;

[0022] P AUT The output power of the antenna under test;

[0023] I AThis refers to cable loss in the receiving link.

[0024] As a further explanation of the present invention, preferably, the output power of the antenna under test satisfies:

[0025] P AUT =EIRP-I D +G AUT

[0026] in,

[0027] EIRP is the effective radiated power;

[0028] I D For free space loss;

[0029] G AUT This represents the gain of the antenna under test.

[0030] As a further explanation of the present invention, preferably, the free space loss satisfies:

[0031] I D =32.45+20lgR+20lgf

[0032] in,

[0033] R represents the transmission path;

[0034] f is the test frequency.

[0035] (III) Beneficial Effects

[0036] The above-described technical solution of the present invention has the following advantages:

[0037] This invention creates a new mapping method by utilizing readily available microwave anechoic chambers and equipment, which can quickly and easily obtain the antenna pattern of an antenna in the state of a full-size target. This solves the problem that in the past, antenna patterns could only be measured and obtained individually, which led to abnormal signal transmission and reception of the full-size target after the antenna was installed in the working state. Attached Figure Description

[0038] Figure 1 This is a schematic diagram of the test system configuration of the present invention;

[0039] Figure 2 This is a top view of the microwave anechoic chamber compressed field of the present invention;

[0040] Figure 3 This is a front view of the microwave anechoic chamber compressed field of the present invention.

[0041] In the diagram: 1. Signal source; 2. Power amplifier; 3. Transmitting antenna; 4. Antenna under test; 5. Full-size target; 6. Spectrum analyzer; 7. Turntable; 8. Support frame; 9. Computer. Detailed Implementation

[0042] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0043] A method for plotting antenna radiation patterns under full-size target conditions, the method being based on the following device:

[0044] like Figure 1 As shown, the system includes a full-band coverage signal source 1, a power amplifier 2, a transmitting antenna 3, an antenna under test 4, a spectrum analyzer 6, a high-precision one-dimensional turntable 7, a high-transmittance foam support frame for the target under test (compatible with microwave anechoic chambers) 8, and a computer 9. The signal source 1, power amplifier 2, and transmitting antenna 3 are located at the transmitting end of the microwave anechoic chamber's compact field. The signal source 1 is electrically connected to the power amplifier 2, and the power amplifier 2 is electrically connected to the transmitting antenna 3 to form a transmitting link. The antenna under test 4, a full-size target 5, the spectrum analyzer 6 (or vector network analyzer), the turntable 7, the support frame 8, and the computer 9 are located at the receiving end of the microwave anechoic chamber's compact field. The antenna under test 4 is electrically connected to the spectrum analyzer 6, and the spectrum analyzer 6 is electrically connected to the turntable 7, or connected to the turntable 7 via the computer 9 to form a receiving link. The full-size target 5 is placed behind the antenna under test 4.

[0045] Combination Figure 2 , Figure 3 The drawing method provided by this invention specifically includes the following steps:

[0046] I. Determine the dimensions of the quiet zone in the microwave anechoic chamber (W0×H0×L0), the dimensions of the full-size target 5 (W1×H1×L1), the center point O of the quiet zone, and the position A of the center of gravity of the full-size target 5. Confirm that the aperture of the antenna under test 4 is located at position B of the full-size target 5.

[0047] II. Adjust the center of gravity A of the full-size target 5 to point O, which is located in the quiet zone along with the rotation axis of the turntable 7; calculate the distance L between the aperture of the antenna under test 4 and point O, based on the center of gravity A of the full-size target 5 and the aperture B of the antenna under test 4. AB Determine the distance L AB If both W0 and L0 are less than 0, it means that the antenna under test 4 remains within the quiet zone throughout the rotation process.

[0048] III. Place the full-size target 5 on the support frame 8 in its working state, and adjust the height of the support frame 8 so that the center height of the antenna under test 4 is the same as the center point O of the quiet zone.

[0049] IV. Set the polarization of the transmitting antenna to 3 according to the test requirements and connect the transmitting link; set the polarization and installation angle of the antenna under test to 4 and connect the receiving link.

[0050] V. Computer 9 controls turntable 7 to perform one-dimensional planar rotation. The full-size target 5 rotates from a -180° azimuth to +180° in a top-down counter-clockwise direction. During the rotation, turntable 7 transmits the angle signal to spectrum analyzer 6 or computer 9 to calculate the receiver input level P. r :

[0051] P r =P AUT -I A

[0052] in,

[0053] I A Cable loss in the receiving link, in dB;

[0054] P AUT The output power of antenna 4 under test is given in dBm.

[0055] P AUT =EIRP-I D +G AUT

[0056] in,

[0057] G AUT The gain of antenna 4 under test is expressed in dBi.

[0058] EIRP stands for Effective Radiated Power, measured in dBm.

[0059] EIRP = P S -(I1+I2)+G a +G t

[0060] in,

[0061] P S The output power of signal source 1 is expressed in dBm.

[0062] I1+I2 represents the losses of the two cables, in dB.

[0063] G a This represents the gain of power amplifier 2, in dB.

[0064] Gt Here is the gain of transmitting antenna 3, in dBi.

[0065] I D This refers to free space loss, expressed in dB, specifically as follows:

[0066] I D =32.45+20lgR+20lgf

[0067] in,

[0068] R represents the transmission path, measured in meters (m).

[0069] f represents the test frequency, in GHz.

[0070] VI. Based on the test and calculation results, draw the antenna pattern of the full-size target and obtain the differences in installing the full-size target by comparing it with the individual antenna patterns.

[0071] In summary, this invention outputs a signal of a specified frequency and power level from signal source 1. The signal is transmitted to transmitting antenna 3 via a feeder, and then radiates into space, eventually reaching the aperture of the tested antenna 4 in the far field, where it is uniformly illuminated. The tested antenna 4 is in receiving mode, and its polarization is set as required. The tested antenna 4 moves continuously around the center of turntable 7, generating an antenna radiation pattern. By measuring the antenna radiation pattern, antenna radiation parameters such as antenna gain, half-power beamwidth, front-to-back ratio, and cross-polarization discrimination under the full-size target 5 can be calculated. By comparing this with the individual antenna radiation pattern, the differences after installing the full-size target 5 can be observed.

[0072] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for drawing antenna radiation patterns under full-size target conditions, characterized in that: Includes the following steps: Ⅰ. Determine the dimensions of the quiet zone of the microwave anechoic chamber, the full-size target (5), the center point of the quiet zone and the center of gravity of the full-size target (5), and confirm that the aperture of the antenna (4) under test is located at the position of the full-size target (5); II. Adjust the center of gravity of the full-size target (5) to the center point of the quiet zone with the rotation axis of the turntable (7); calculate the distance between the aperture of the antenna under test (4) and the center point of the quiet zone based on the center of gravity of the full-size target (5) and the aperture position of the antenna under test (4); Ⅲ. Place the full-size target (5) on the support frame (8) in the working state, and adjust the height of the support frame (8) so that the center height of the antenna under test (4) is the same as the center point height of the quiet zone; IV. Set the polarization of the transmitting antenna (3) according to the test requirements and connect the transmitting end link; set the polarization and installation angle of the antenna under test (4) and connect the receiving end link; V. The computer (9) controls the turntable (7) to perform a one-dimensional plane rotation, rotating from the full-size target (5) -180° orientation in a top-down counterclockwise direction to +180°. During the rotation, the turntable (7) transmits the angle signal to the spectrum analyzer (6) or the computer (9) to calculate the receiver input level. VI. Based on the test and calculation results, draw the antenna pattern of the full-size target (5) and obtain the differences between the full-size target (5) and the individual antenna pattern by comparison.

2. The method for drawing antenna patterns under full-size target conditions according to claim 1, characterized in that: If the distance between the aperture of the antenna under test (4) and the center point of the quiet zone is less than the size of the quiet zone, then the antenna under test (4) will always be in the quiet zone during the rotation process.

3. The method for drawing antenna patterns under full-size target conditions according to claim 2, characterized in that: The transmitting link includes a signal source (1), a power amplifier (2), and a transmitting antenna (3). The signal source (1) is electrically connected to the power amplifier (2), and the power amplifier (2) is electrically connected to the transmitting antenna.

4. The method for drawing antenna patterns under full-size target conditions according to claim 3, characterized in that: The receiving link includes the antenna under test (4), the spectrum analyzer (6) and the turntable (7). The antenna under test (4) is electrically connected to the spectrum analyzer (6), and the spectrum analyzer (6) is electrically connected to the turntable (7) or connected to the turntable (7) via the computer (9).

5. The method for drawing antenna patterns under full-size target conditions according to claim 4, characterized in that: The receiver input level satisfies: P r =P AUT -I A in, P r This is the receiver input level; P AUT The output power of the antenna under test (4); I A This refers to cable loss in the receiving link.

6. The method for drawing antenna patterns under full-size target conditions according to claim 5, characterized in that: The output power of the antenna under test (4) satisfies: P AUT =EIRP-I D +G AUT in, EIRP is the effective radiated power; I D For free space loss; G AUT This represents the gain of the antenna under test.

7. The method for drawing antenna patterns under full-size target conditions according to claim 6, characterized in that: Free space loss satisfies: I D =32.45+20lgR+20lgf in, R represents the transmission path; f is the test frequency.

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