A polarization isolation degree test device for a satellite communication antenna and a test method thereof

Abstract

The present invention relates to a polarization isolation degree testing device for a satellite communication antenna, which includes an antenna main surface, a sub-reflector, a feed source, a polarization central axis, a polarization motor, a testing turntable, a testing motor and a base. The antenna main surface is fixed on the top surface of the testing turntable. The polarization central axis is rotatably arranged on the testing turntable and is located on the center line of the antenna main surface. The feed source is sleeved on the upper end of the polarization central axis. The sub-reflector is arranged on the top of the feed source. The polarization motor is fixed on the testing turntable. The testing turntable is rotatably arranged on the base. The testing motor is fixed on the base. The polarization motor drives the polarization central axis to rotate through a polarization transmission mechanism. The testing motor drives the testing turntable and the polarization central axis to rotate coaxially through a testing transmission mechanism. The rotation direction of the testing turntable is opposite to the rotation direction of the polarization central axis. The present invention can realize testing the polarization isolation degree corresponding to all polarization angles of the satellite communication antenna at the same longitude and latitude location, with more comprehensive testing and high testing efficiency.

Description

Technical Field

[0001] The present invention relates to the technical field of satellite communication monitoring, and in particular to a polarization isolation test device and a test method for a satellite communication antenna. Background Art

[0002] In satellite communication systems, circular polarization and linear polarization are usually used to achieve a larger communication bandwidth within a limited bandwidth. Currently, the commonly used C-band and Ku-band satellite communication systems usually use linear polarization, which is divided into horizontal polarization and vertical polarization. Theoretically, two orthogonal polarization waves should be completely isolated, which means that an antenna can be configured with two receiving or transmitting ports, each port only matches one polarization wave, and is completely orthogonal to the other polarization wave. In satellite communication systems, frequency reuse can be performed using the characteristic of orthogonal polarization, that is, two different polarization modes can be used to transmit two different signals in the same frequency band, and as long as there is sufficient polarization isolation between the two, they will not interfere with each other. In engineering, the indicator that measures the performance of the polarization isolation characteristic of satellite antenna equipment is called polarization isolation. The degree of polarization isolation directly affects the communication effect of satellite communication antennas. Some satellite communication antennas are prohibited by satellite companies because of too small polarization isolation, which interferes with satellite resources.

[0003] Under normal circumstances, the polarization of satellite downlink signals is not ideally horizontal or vertical to the ground, but varies with the longitude and latitude of the earth where the satellite communication antenna is located. In order to make the receiving polarization direction of the satellite communication antenna consistent with the polarization direction of the satellite downlink signal, the OMT (orthogonal mode converter) waveguide port behind the feed source needs to be tilted at an angle relative to the ground when receiving the satellite downlink signal. This angle is called the polarization angle of the satellite communication antenna in the satellite system.

[0004] The existing method for testing polarization isolation of satellite communication antennas is as follows: first, the satellite communication antenna under test is aligned with the test satellite, and a CW continuous wave signal specified by the satellite company is transmitted at a polarization angle through the satellite communication antenna under test. The satellite main station simultaneously receives the horizontal polarization signal and the vertical polarization signal, and the difference in the strength of the two polarization signals is compared with the help of a spectrum analyzer to obtain the polarization isolation of the satellite communication antenna.

[0005] The above satellite communication antenna polarization isolation degree test method can only test the polarization isolation degree of a satellite communication antenna at one or two polarization angles. For example, the Chinese patent with the publication number CN114171918A discloses a calibration method for the polarization isolation degree of a satellite mobile communication antenna. Although it can automatically and accurately calibrate the polarization isolation degree of the satellite communication antenna and is not limited by third-party equipment such as satellite master stations, during its test process, when changing the polarization angle by controlling the polarization axis, it can only test the polarization isolation degree at two polarization angles of the satellite communication antenna. However, during the use of the satellite communication antenna, the polarization angles used change continuously with the longitude and latitude information of the satellite communication antenna and the satellite orbit information. Therefore, the existing satellite communication antenna polarization isolation degree test methods cannot test the polarization isolation degrees corresponding to all the polarization angles required for the satellite communication antenna at a single longitude and latitude location, that is, they cannot ensure that the polarization isolation degree of the satellite communication antenna meets the requirements of the satellite company when it is used globally after leaving the factory. Summary of the Invention

[0006] The purpose of the present invention is to overcome the shortcomings of the prior art and provide a polarization isolation degree test device for satellite communication antennas, which can realize the test of the polarization isolation degrees corresponding to all polarization angles of the satellite communication antenna at the same longitude and latitude location, with more comprehensive testing and high testing efficiency.

[0007] The purpose of the present invention is achieved through the following technical solutions:

[0008] A polarization isolation degree test device for satellite communication antennas includes an antenna main surface, a sub-reflector, a feed, a polarization central axis, a polarization motor, a test turntable, a test motor, and a base. The antenna main surface is fixed to the top surface of the test turntable. The polarization central axis is rotatably arranged on the test turntable and is located on the center line of the antenna main surface. The feed is sleeved on the upper end of the polarization central axis. The sub-reflector is arranged on the top of the feed. The polarization motor is fixed to the test turntable. The test turntable is rotatably arranged on the base. The test motor is fixed to the base. The polarization motor drives the polarization central axis to rotate through a polarization transmission mechanism. The test motor drives the test turntable and the polarization central axis to rotate coaxially through a test transmission mechanism. The rotation direction of the test turntable is opposite to the rotation direction of the polarization central axis.

[0009] Further, an orthomode transducer and an up-conversion power amplifier for cooperating with the feed are arranged at the lower end of the polarization central axis.

[0010] Further, the test turntable includes a top plate, a bottom plate, and a support rod. The top plate is fixedly connected to the bottom plate through the support rod. The antenna main surface is fixed to the top surface of the top plate. The polarization central axis is rotatably connected to the top plate through a rotating bearing. The upper end of the polarization central axis passes upward through the antenna main surface, and the lower end of the polarization central axis passes downward through the top plate. The polarization motor is fixed to the bottom surface of the top plate. The bottom plate is rotatably arranged on the base.

[0011] Furthermore, the polarization drive mechanism includes a polarization pulley and a transmission belt. The polarization pulley is fixed to the lower end of the polarization central axis, and the polarization motor drives the polarization pulley to rotate through the transmission belt.

[0012] Furthermore, a rotating seat is fixed to the bottom of the bottom plate, and the rotating seat is rotatably connected to the base through a rotating bearing.

[0013] Furthermore, the test drive mechanism includes a driving gear and a driven gear. The driving gear is fixed to the output shaft of the test motor, the driven gear is fixed on the rotating seat, and the driving gear and the driven gear mesh with each other.

[0014] According to the above polarization isolation degree test device for a satellite communication antenna, the present invention also provides a test method corresponding to the test device, which includes the following steps:

[0015] S1. Install the main surface of the antenna, the sub-reflector, the feed source, the polarization central axis, the polarization motor, the test turntable, the test motor and the base, so that the main surface of the antenna, the sub-reflector and the feed source form a satellite communication antenna. Adjust the positions of the satellite communication antenna and the test turntable through the polarization motor and the test motor, so that the satellite communication antenna and the test turntable are simultaneously aligned with the satellite to be measured, and then transmit a CW continuous wave to the satellite to be measured through the satellite communication antenna.

[0016] S2. Receive and observe the horizontal polarization signal and the vertical polarization signal of the satellite communication antenna through the satellite main station, and drive the sub-reflector and the feed source to continue to rotate with the polarization central axis through the polarization motor, so that the polarization isolation degree of the satellite communication antenna reaches the maximum value.

[0017] S3. Drive the satellite communication antenna and the polarization central axis to rotate by an angle simultaneously with the test turntable through the test motor.

[0018] S4. Drive the sub-reflector and the feed source to rotate in the opposite direction by the same angle relative to the test turntable with the polarization central axis through the polarization motor, so that the polarization angle of the CW continuous wave emitted by the satellite communication antenna to the satellite to be measured reaches the optimal polarization angle.

[0019] S5. Receive and record the signal difference between the horizontal polarization signal and the vertical polarization signal of the satellite communication antenna through the satellite main station.

[0020] Furthermore, in step S2, the maximum value of the polarization isolation degree of the satellite communication antenna (1) is not less than 30 dB.

[0021] The present invention has the following advantages:

[0022] 1. Through the settings of the main antenna surface, sub-reflector, feed, polarization central axis, polarization motor, test turntable, test motor and base, the main antenna surface, sub-reflector and feed are installed and combined into a satellite communication antenna. The polarization angle of the communication antenna is adjusted by using the polarization motor, test turntable and test motor, and the polarization isolation corresponding to all polarization angles of the satellite communication antenna can be tested at the same longitude and latitude location, improving the production test coverage of satellite communication equipment, avoiding the risk of satellite polarization interference, and thus ensuring that the polarization isolation of the satellite communication antenna can meet the requirements of satellite companies.

[0023] 2. During the test process, the polarization motor and test motor can be automatically controlled by using a motor controller, and then the automatic adjustment of the polarization angle of the satellite communication antenna can be realized, improving the test efficiency and polarization adjustment accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 is the overall structural schematic diagram of the present invention;

[0025] Figure 2 is Figure 1 the installation structural schematic diagram of the satellite communication antenna and the polarization motor in

[0026] Figure 3 is Figure 1 the installation structural schematic diagram of the test turntable and the test motor in

[0027] Figure 4 is the working process schematic diagram of the present invention;

[0028] In the figure: 1, satellite communication antenna; 11, sub-reflector; 12, feed; 13, orthomode transducer; 14, up-conversion power amplifier; 2, main antenna surface; 3, polarization central axis; 4, polarization motor; 5, test turntable; 51, top plate; 52, bottom plate; 53, support rod; 6, test motor; 7, base; 8, rotating bearing; 9, polarization pulley; 10, transmission belt; 15, rotating seat; 16, driving gear; 17, driven gear. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0029] The following further describes the present invention with reference to the accompanying drawings, but the protection scope of the present invention is not limited to the following.

[0030] Such as Figures 1 - 3As shown in the figure, a polarization isolation degree testing device for a satellite communication antenna includes an antenna main surface 2, a sub-reflector 11, a feed 12, a polarization central axis 3, a polarization motor 4, a test turntable 5, a test motor 6, and a base 7. Among them, the antenna main surface 2, the sub-reflector 11, and the feed 12 together constitute the satellite communication antenna 1. The polarization central axis 3 is located on the center line of the antenna main surface 2. The feed 12 is sleeved on the upper end of the polarization central axis 3. The sub-reflector 11 is arranged on the top of the feed 12. The antenna main surface 2 and the polarization motor 4 are fixedly installed on the test turntable 5 through bolts. The test motor 6 is fixedly installed on the base 7 through bolts. The polarization motor 4 can drive the polarization central axis 3 to rotate on the test turntable 5 through a polarization transmission mechanism. The test motor 6 can drive the test turntable 5 to rotate coaxially with the polarization central axis 3 on the base 7 through a test transmission mechanism, and the rotation direction of the test turntable 5 is opposite to the rotation direction of the polarization central axis 3.

[0031] An orthomode transducer 13 and an up-conversion power amplifier 14 are installed at the lower end of the polarization central axis 3. Among them, the up-conversion power amplifier 14 is used to frequency-convert and power-amplify the L-band signal output by the satellite modem, and finally transmit the signal to the orthomode transducer 13. The orthomode transducer 13, as a microwave component for separating or mixing two mutually orthogonal polarization waves, mixes the single polarization wave output by the up-conversion power amplifier 14 and radiates it through the feed 12. At the same time, it separates the two mutually orthogonal polarization waves radiated from the satellite to the spectrum analyzer at the signal receiving end. The feed 12 is used to radiate the radio frequency power output by the up-conversion power amplifier 13 in the form of electromagnetic waves to the sub-reflector 11. The sub-reflector 11 is used to regularly reflect the electromagnetic wave radiation energy radiated by the feed 12 onto the antenna main surface 2. The antenna main surface 2 is a conductive curved surface used to concentrate and reflect the electromagnetic waves emitted by the sub-reflector 11 in a certain direction according to certain requirements to enhance the emission effect.

[0032] Specifically, such as Figure 1 、 2As shown, the test turntable 5 includes a top plate 51, a bottom plate 52, and a support rod 53. Among them, the top plate 51 is fixedly connected to the bottom plate 52 through the support rod 53, so that the top plate 51 is supported by the support rod 53 above the bottom plate 52. The bottom plate 52 is rotatably arranged on the base 7. Preferably, the top plate 51 and the bottom plate 52 are horizontal. The main surface 2 of the antenna is fixedly bolted to the top surface of the top plate 51. The polarization central axis 3 is rotatably connected to the top plate 51 through a rotary bearing 8. The upper end of the polarization central axis 3 passes upward through the main surface 2 of the antenna, and the lower end passes downward through the top plate 51. The polarization motor 4 is fixedly installed by bolts on the bottom surface of the top plate 51. The feed 12 is sleeved on the upper end of the polarization central axis 3. The sub-reflector 11 is arranged on the top of the feed 12. The orthomode transducer 13 and the up-conversion power amplifier 14 are arranged at the lower end of the polarization central axis 3. The radiation of both the main surface 2 of the antenna and the sub-reflector 11 is realized through space. Therefore, when installing the two, as long as the relative positions of the foci are satisfied. When installing the feed 12, the orthomode transducer 13, and the up-conversion power amplifier 14, the RF components can be directly combined seamlessly and precisely with screws.

[0033] As Figure 2 shown, the polarization transmission mechanism includes a polarization pulley 9 and a transmission belt 10. Among them, the polarization pulley 9 is fixed to the lower end of the polarization central axis 3. The polarization motor 4 drives the polarization pulley 9 to rotate through the transmission belt 10, and then drives the polarization central axis 3 to rotate with the center line of the main surface 2 of the antenna as the rotation axis line. When the polarization central axis 3 rotates, it also drives the entire satellite communication antenna 1 to rotate accordingly, so as to realize the adjustment of the polarization angle of the satellite communication antenna 1.

[0034] As Figure 3 shown, a rotating seat 15 is fixedly bolted to the bottom of the bottom plate 52. The rotating seat 15 is rotatably connected to the base 7 through a rotary bearing 8. The test transmission mechanism includes a driving gear 16 and a driven gear 17. Among them, the driving gear 16 is fixed to the output shaft of the test motor 6, and the driven gear 17 is fixed on the rotating seat 15. The driving gear 16 and the driven gear 17 mesh with each other. Preferably, the rotation center line of the rotating seat 15 is collinear with the center line of the main surface 2 of the antenna. In this way, when the test motor 6 drives the bottom plate 52 to rotate through the driving gear 16 and the driven gear 17, the entire test turntable 5 rotates coaxially with the polarization central axis 3.

[0035] When using the above-mentioned polarization isolation degree test device for the satellite communication antenna 1 to conduct a polarization isolation degree test, the entire test process is as Figure 4 shown, and mainly includes the following steps:

[0036] S1. Install the main antenna surface 2, sub-reflector 11, feed 12, polarization central axis 3, polarization motor 4, test turntable 5, test motor 6 and base 7, so that the main antenna surface 2, sub-reflector 11 and feed 12 form a satellite communication antenna 1. Adjust the positions of the satellite communication antenna 1 and the test turntable 5 through the polarization motor 4 and the test motor 6, so that the satellite communication antenna 1 and the test turntable 5 are simultaneously aligned with the satellite to be measured. Then, transmit a CW continuous wave to the satellite to be measured through the satellite communication antenna 1.

[0037] Specifically, first fix the base 7, and then install the main antenna surface 2, sub-reflector 11, feed 12, polarization central axis 3, polarization motor 4, test turntable 5 and test motor 6. Both the polarization motor 4 and the test motor 6 are preferably stepper motors. After installation, connect the polarization motor 4 and the test motor 6 to the motor controller. This process is a conventional technical means and will not be elaborated in detail here.

[0038] S2. Receive and observe the signal difference between the horizontal polarization signal and the vertical polarization signal of the satellite communication antenna 1 through the satellite master station, and drive the sub-reflector 11 and the feed 12 to continue rotating along with the polarization central axis 3 through the polarization motor 4, so that the polarization isolation of the satellite communication antenna 1 reaches the maximum value.

[0039] Specifically, the satellite master station receives the CW continuous waves on horizontal polarization and vertical polarization, and connects the received CW continuous wave signals to a spectrum analyzer. Then, observe the signal difference between the CW continuous wave signals on horizontal polarization and vertical polarization through the spectrum analyzer, that is, the polarization isolation of the satellite communication antenna 1.

[0040] According to the requirements of the IntelSat organization and domestic satellite companies, the polarization isolation of the linearly polarized satellite communication antenna 1 should reach at least 30 dB. Therefore, in this step, the maximum value of the polarization isolation of the satellite communication antenna 1 should not be less than 30 dB.

[0041] S3. Drive the satellite communication antenna 1 and the polarization central axis 3 to rotate an angle simultaneously along with the test turntable 5 through the test motor 6.

[0042] Specifically, if the test motor 6 drives the test turntable 5 to rotate clockwise by x o , then the satellite communication antenna 1 and the polarization central axis 3 will also rotate clockwise by x o . At this time, the polarization angle of the CW continuous wave emitted by the satellite communication antenna 1 to the satellite is offset by x o ; correspondingly, if the test motor 6 drives the test turntable 5 to rotate counterclockwise by -x o , then the satellite communication antenna 1 and the polarization central axis 3 will also rotate counterclockwise by -x o . At this time, the polarization angle of the CW continuous wave emitted by the satellite communication antenna 1 to the satellite is also offset by xo , where "-" only indicates the opposite rotation direction.

[0043] S4. Drive the sub-reflector 11 and the feed 12 to rotate in the opposite direction at the same angle relative to the test turntable 5 along the polarization central axis 3 by the polarization motor 4, so that the polarization angle of the CW continuous wave emitted by the satellite communication antenna 1 to the satellite under test reaches the optimal polarization angle.

[0044] Specifically, taking the rotation angle of the test turntable 5 driven by the test motor 6 in step S3 as 5° as an example, the polarization angle of the CW continuous wave emitted by the satellite communication antenna 1 to the satellite is offset by 5°. If the test turntable 5 rotates clockwise by 5°, then in this step, drive the polarization central axis 3 to rotate counterclockwise by -5° by the polarization motor 4, so that the polarization angle of the CW continuous wave emitted by the satellite communication antenna 1 to the satellite under test reaches the optimal polarization angle, that is, make the receiving polarization direction of the satellite communication antenna 1 consistent with the polarization direction of the satellite downlink signal; similarly, if the test turntable 5 rotates counterclockwise by 5°, then it is only necessary to make the polarization central axis 3 rotate clockwise by -5°, where "-" only indicates the opposite rotation direction.

[0045] S5. Receive and record the signal difference between the horizontal polarization signal and the vertical polarization signal of the satellite communication antenna 1 by the satellite master station.

[0046] Specifically, after the operations of S3 and S4, use a spectrum analyzer to observe the signal difference between the horizontal polarization signal and the vertical polarization signal of the satellite communication antenna 1 received by the satellite master station, and then obtain the polarization isolation degree of the final test. Repeat steps S3 and S4 until all polarization angles are covered and tested, and record all measured polarization isolation degrees.

[0047] Through the above test method, the polarization isolation degrees corresponding to all polarization angles of the satellite communication antenna 1 can be tested at the same longitude and latitude location, thereby improving the production test coverage of the satellite communication equipment, avoiding the risk of satellite polarization interference, and ensuring that the polarization isolation degrees of the satellite communication antenna 1 can meet the requirements of the satellite company. During the test process, the polarization motor 4 and the test motor 6 can be automatically controlled by the motor controller, so that the automatic adjustment of the polarization angle of the satellite communication antenna 1 can be realized, and the test efficiency and the polarization adjustment accuracy are improved.

[0048] Although the embodiments of the present invention have been shown and described, those of ordinary skill in the art can understand that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirits of the present invention. The scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A polarization isolation degree test device for a satellite communication antenna, characterized in that: It includes an antenna main surface (2), a sub-reflector (11), a feed source (12), a polarization central axis (3), a polarization motor (4), a test turntable (5), a test motor (6) and a base (7). The antenna main surface (2) is fixed on the test turntable (5). The polarization central axis (3) is rotatably arranged on the test turntable (5). The polarization central axis (3) is located on the center line of the antenna main surface (2). The feed source (12) is sleeved on the upper end of the polarization central axis (3). The sub-reflector (11) is arranged on the top of the feed source (12). The polarization motor (4) is fixed on the test turntable (5). The test turntable (5) is rotatably arranged on the base (7). The test motor (6) is fixed on the base (7). The polarization motor (4) drives the polarization central axis (3) to rotate through a polarization transmission mechanism. The test motor (6) drives the test turntable (5) and the polarization central axis (3) to rotate coaxially through a test transmission mechanism. The rotation direction of the test turntable (5) is opposite to the rotation direction of the polarization central axis (3). The test turntable (5) includes a top plate (51), a bottom plate (52) and a support rod (53). The top plate (51) is fixedly connected to the bottom plate (52) through the support rod (53). The antenna main surface (2) is fixed on the top surface of the top plate (51). The polarization central axis (3) is rotatably connected to the top plate (51) through a rotating bearing (8). The upper end of the polarization central axis (3) passes upward through the antenna main surface (2). The lower end of the polarization central axis (3) passes downward through the top plate (51). The polarization motor (4) is fixed on the bottom surface of the top plate (51). The bottom plate (52) is rotatably arranged on the base (7). A rotating seat (15) is fixed at the bottom of the bottom plate (52). The rotating seat (15) is rotatably connected to the base (7) through a rotating bearing (8).

2. The polarization isolation degree test device for a satellite communication antenna according to claim 1, characterized in that: An orthogonal mode converter (13) and an up-conversion power amplifier (14) that cooperate with the feed source (12) are provided at the lower end of the polarization central axis (3).

3. The polarization isolation degree test device for a satellite communication antenna according to claim 1, characterized in that: The polarization transmission mechanism includes a polarization pulley (9) and a transmission belt (10). The polarization pulley (9) is fixed at the lower end of the polarization central axis (3). The polarization motor (4) drives the polarization pulley (9) to rotate through the transmission belt (10).

4. The polarization isolation degree test device for a satellite communication antenna according to claim 1, characterized in that: The test transmission mechanism includes a driving gear (16) and a driven gear (17). The driving gear (16) is fixed on the output shaft of the test motor (6). The driven gear (17) is fixed on the rotating seat (15). The driving gear (16) and the driven gear (17) are meshed with each other.

5. The test method of the polarization isolation degree test device for a satellite communication antenna according to claim 1, characterized in that, it includes the following steps: S1. Install the main antenna surface (2), sub-reflector (11), feed (12), polarization central axis (3), polarization motor (4), test turntable (5), test motor (6) and base (7) so that the main antenna surface (2), sub-reflector (11) and feed (12) form a satellite communication antenna (1). Adjust the positions of the satellite communication antenna (1) and the test turntable (5) through the polarization motor (4) and the test motor (6) so that the satellite communication antenna (1) and the test turntable (5) are simultaneously aligned with the satellite to be measured. Then, transmit CW continuous wave to the satellite to be measured through the satellite communication antenna (1). S2. Receive and observe the signal difference between the horizontal polarization signal and the vertical polarization signal of the satellite communication antenna (1) through the satellite main station, and drive the sub-reflector (11) and the feed (12) to continue rotating along the polarization central axis (3) through the polarization motor (4) so that the polarization isolation of the satellite communication antenna (1) reaches the maximum value. S3. Drive the satellite communication antenna (1) and the polarization central axis (3) to rotate by an angle simultaneously with the test turntable (5) through the test motor (6). S4. Drive the sub-reflector (11) and the feed (12) to rotate in the opposite direction at the same angle relative to the test turntable (5) along the polarization central axis (3) through the polarization motor (4) so that the polarization angle of the CW continuous wave transmitted by the satellite communication antenna (1) to the satellite to be measured reaches the optimal polarization angle. S5. Receive and record the signal difference between the horizontal polarization signal and the vertical polarization signal of the satellite communication antenna (1) through the satellite main station.

6. The test method of the polarization isolation test device for satellite communication antenna according to claim 5, characterized in that: in step S2, the maximum value of the polarization isolation of the satellite communication antenna (1) is not less than 30 dB.

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