Antenna pattern drawing method under full-size target condition

Abstract

The invention relates to a method for drawing an antenna pattern under a full-size target condition, which relates to the field of testing and comprises the following steps of: adjusting the center-of-gravity position of a full-size target to a central point which is positioned in a dead zone with the rotation axis of a turntable; calculating the distance between the aperture of the to-be-measured antenna and the central point of the quiet zone according to the gravity center position of the full-size target and the aperture position of the to-be-measured antenna; the central height of the to-be-tested antenna is the same as the central point height of the quiet area by adjusting the support frame; transmitting antenna polarization is set, and a transmitting end link is connected; setting the polarization and installation angle of a to-be-tested antenna, and connecting a receiving end link; the computer controls the rotary table to rotate from a full-size target 180-degree azimuth to a full-size target 180-degree azimuth in an overlook anticlockwise direction to a full-size target 180-degree azimuth, the rotary table transmits an angle signal to the spectrum analyzer or the computer in the rotating process, and an antenna pattern of the full-size target can be drawn according to test and calculation results. The method has the advantage that the antenna pattern of the antenna in the full-size target state can be quickly, simply and conveniently obtained.

Description

Technical Field

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

[0002] Usually the antenna is used in its far field condition, so to correctly test the radiation characteristics of the antenna, first of all, there must be a test field that can provide uniform plane electromagnetic waves to illuminate the antenna to be tested. The test field types are mainly divided into outdoor test fields and indoor test fields. In practical applications, due to the influence of direct waves or reflected waves in the outdoor field, according to the minimum test distance formula It is difficult to achieve far-field conditions with full-band coverage, so it is usually tested in a compact microwave darkroom that can better simulate free space. It has the advantages of all-weather, wide bandwidth, good shielding performance, security and confidentiality.

[0003] Generally, in antenna pattern testing, the antenna pattern is only tested separately in a microwave darkroom. However, many antennas often need to be installed on various target carriers, such as satellites and other carriers that rely on radar antennas to send and receive signals. The accuracy of the antenna pattern is crucial, especially the accuracy of the antenna pattern in the full-size target state after installation. The antenna is likely to be affected by installation tolerances, obstruction of the target shape after installation, internal losses such as cables and connectors after installation, and the influence of other antennas along the cavity or metal surface, resulting in the main lobe and side lobe amplitude or directivity of the antenna being affected, thereby greatly affecting the function of the antenna.

[0004] Therefore, in view of the above shortcomings, it is necessary to provide an antenna pattern drawing method under full-size target conditions. Summary of the invention

[0005] 1. Technical issues to be resolved

[0006] The technical problem to be solved by the present invention is to solve the problem that in the past, antennas could only measure and obtain their antenna patterns individually, resulting in abnormal signal transmission and reception of full-size targets after the antennas are installed when in working state.

[0007] (II) Technical solution

[0008] In order to solve the above technical problems, the present invention provides a method for drawing an antenna pattern under full-size target conditions, comprising the following steps:

[0009] Ⅰ. Determine the size of the quiet zone and full-size target in the compact field of the microwave darkroom, as well as the center point of the quiet zone and the center of gravity of the full-size target, and confirm that the antenna aperture to be tested is located at the position of the full-size target;

[0010] Ⅱ. Adjust the center of gravity of the full-size target to the center point of the quiet zone with the rotation axis of the turntable; calculate the distance between the antenna aperture to be tested and the center point of the quiet zone according to the center of gravity of the full-size target and the position of the antenna aperture to be tested;

[0011] III. Place the full-size target on the support frame at the working attitude angle, and adjust the height of the support frame to make the center height of the antenna to be tested the same as the center point height of the quiet zone;

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

[0013] V. The computer controls the turntable to rotate in one-dimensional plane, from -180° to +180° in the anti-clockwise direction when looking down at the full-size target. During the rotation, the turntable transmits the angle signal to the spectrum analyzer or computer to calculate the receiver input level;

[0014] VI. Based on the test and calculation results, draw the antenna radiation pattern of the full-size target, and obtain the difference of installing the full-size target by comparing it with the single antenna radiation pattern.

[0015] As a further illustration of the present invention, preferably, if the distance between the aperture face of the antenna to be tested and the center point of the quiet zone is smaller than the size of the quiet zone, the antenna to be tested is always in the quiet zone during the rotation process.

[0016] As a further illustration of the present invention, preferably, the transmitting end link includes a signal source, a power amplifier and a transmitting antenna, 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 illustration of the present invention, preferably, the receiving end link includes an antenna to be tested, a spectrum analyzer and a turntable, the antenna to be tested is electrically connected to the spectrum analyzer, and the spectrum analyzer is electrically connected to the turntable or is electrically connected to the turntable through a computer.

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

[0019] P r =P AUT -I A

[0020] in,

[0021] P r Input level for the receiver;

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

[0023] I Ais the cable loss in the receive link.

[0024] As a further illustration of the present invention, preferably, the output power of the antenna to be tested satisfies:

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

[0026] in,

[0027] EIRP is the effective radiated power;

[0028] I D is the free space loss;

[0029] G AUT is the antenna gain to be measured.

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

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

[0032] in,

[0033] R is the transmission path;

[0034] f is the test frequency.

[0035] (III) Beneficial effects

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

[0037] The present invention creates a new drawing method by utilizing the existing microwave darkroom and equipment, which can quickly and easily obtain the antenna radiation pattern of the antenna in the full-size target state, thereby solving the problem that the antenna can only be measured and obtained by a single antenna in the past, resulting in abnormal sending and receiving signals of the full-size target in the working state after the antenna is installed. BRIEF DESCRIPTION OF THE DRAWINGS

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

[0039] Figure 2 This is a top view of the compact microwave darkroom of the present invention;

[0040] Figure 3 It is a front view of the compact field of microwave darkroom of the present invention.

[0041] In the figure: 1. signal source; 2. power amplifier; 3. transmitting antenna; 4. antenna to be tested; 5. full-size target; 6. spectrum analyzer; 7. turntable; 8. support frame; 9. computer. DETAILED DESCRIPTION

[0042] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are 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 creative work are within the scope of protection of the present invention.

[0043] A method for drawing antenna patterns under full-size target conditions, the method is based on the following equipment:

[0044] like Figure 1 As shown, it includes a signal source 1 covering the full band, a power amplifier 2, a transmitting antenna 3, an antenna to be tested 4, a spectrum analyzer 6, a high-precision one-dimensional turntable 7, a foam support frame 8 of the target to be tested with high wave transmittance that meets the requirements of a microwave darkroom, and a computer 9. The signal source 1, the power amplifier 2, and the transmitting antenna 3 are located at the transmitting end of the compact field of the microwave darkroom, 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 end link. The antenna to be tested 4, the 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 compact field of the microwave darkroom. The antenna to be tested 4 is electrically connected to the spectrum analyzer 6, and the spectrum analyzer 6 is electrically connected to the turntable 7 or is electrically connected to the turntable 7 through the computer 9 to form a receiving end link. The full-size target 5 is placed behind the antenna to be tested 4.

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

[0046] Ⅰ. Determine the dimensions of the quiet zone of the compact field of the microwave darkroom W0×H0×L0, the dimensions of the full-size target 5 W1×H1×L1, as well as the center point O of the quiet zone and the center of gravity position A of the full-size target 5, and confirm that the 4th surface of the antenna to be tested is located at the position B of the full-size target 5.

[0047] Ⅱ. Adjust the center of gravity position A of the full-size target 5 to the center point O of the quiet zone with the rotation axis of the turntable 7; calculate the distance L between the surface of the antenna 4 to be tested and the center point O of the quiet zone according to the center of gravity position A of the full-size target 5 and the surface position B of the antenna 4 to be tested. AB ; Determine the distance L AB At the same time, it is smaller than W0 and L0, which means that the antenna 4 to be tested is always within the quiet zone during the rotation process.

[0048] III. Place the full-size target 5 on the support frame 8 at a working attitude angle, and adjust the height of the support frame 8 so that the center height of the antenna 4 to be tested is the same as the center point O of the quiet zone.

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

[0050] Ⅴ. The computer 9 controls the turntable 7 to rotate in one-dimensional plane. The full-size target 5 rotates from -180° to +180° in a counterclockwise direction when looking down. 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 P r :

[0051] P r =P AUT -I A

[0052] in,

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

[0054] P AUT is the output power of the antenna 4 to be tested, in dBm, specifically:

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

[0056] in,

[0057] G AUT is the gain of the antenna 4 to be tested, in dBi;

[0058] EIRP is the effective radiated power, in dBm, specifically;

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

[0060] in,

[0061] P S is the output power of signal source 1, in dBm;

[0062] I1+I2 is the loss of the two cables, in dB;

[0063] G a is the gain of power amplifier 2, in dB;

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

[0065] I D is the free space loss in dB, specifically;

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

[0067] in,

[0068] R is the transmission path, in m;

[0069] f is the test frequency in GHz.

[0070] VI. Based on the test and calculation results, draw the antenna radiation pattern of the full-size target, and obtain the difference of installing the full-size target by comparing it with the single antenna radiation pattern.

[0071] In summary, the present invention outputs a signal of a specified frequency and power level through a signal source 1, and the signal is transmitted to a transmitting antenna 3 through a feeder line. The transmitting antenna 3 radiates into space and finally reaches the aperture of the antenna 4 under test in the far field, and evenly illuminates it. The antenna 4 under test is in a receiving state, and the polarization is set as required. The antenna 4 under test moves continuously around the center of the turntable 7 to draw an antenna pattern. The antenna radiation parameters such as antenna gain, half-power beam width, front-to-back ratio, and cross-polarization discrimination rate under the full-size target 5 state can be calculated by measuring the antenna pattern. By comparing with the single antenna pattern, the difference after the full-size target 5 is installed can be known.

[0072] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for drawing antenna patterns under full-size target conditions, characterized in that: The following steps are involved: Ⅰ. Determine the size of the quiet zone of the compact field of the microwave darkroom and the full-size target (5), as well as 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 to be tested (4) 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 respect to the rotation axis of the turntable (7); calculate the distance between the aperture of the antenna to be tested (4) and the center point of the quiet zone according to the center of gravity of the full-size target (5) and the aperture position of the antenna to be tested (4); III. Place the full-size target (5) on the support frame (8) at a working attitude angle, and adjust the height of the support frame (8) so that the center height of the antenna to be tested (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 to be tested (4) and connect the receiving end link; V. The computer (9) controls the turntable (7) to rotate in a one-dimensional plane from the -180° azimuth of the full-size target (5) to +180° in a counterclockwise direction when viewed from above. During the rotation, the turntable (7) transmits an 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, the antenna radiation pattern of the full-size target (5) is drawn, and the difference of installing the full-size target (5) is obtained by comparing it with the single antenna radiation pattern.

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 (4) to be tested and the center point of the quiet zone is smaller than the size of the quiet zone, the antenna (4) to be tested is always within 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 end link comprises 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 end link comprises an antenna to be tested (4), a spectrum analyzer (6) and a turntable (7); the antenna to be tested (4) is electrically connected to the spectrum analyzer (6), and the spectrum analyzer (6) is electrically connected to the turntable (7) or is electrically connected to the turntable (7) via a 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 meets the following requirements: P r =P AUT -I A in, P r Input level for the receiver; P AUT is the output power of the antenna (4) to be tested; I A is the cable loss in the receive 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 to be tested (4) satisfies: P AUT =EIRP-I D +G AUT in, EIRP is the effective radiated power; I D is the free space loss; G AUT is the antenna gain to be measured.

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 is the transmission path; f is the test frequency.

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