A Dual-Circular Polarization Cassegrain Antenna for LEO Satellite Communication

Abstract

The present invention discloses a dual-circularly polarized Cassegrain antenna applied to LEO low-earth orbit satellite communication, which includes a main reflector. The main reflector is in a parabolic shape, and its inner surface is the main reflecting surface. A through hole is provided at the center of the main reflector. A connection tray is detachably arranged on the outer surface of the main reflector and outside the through hole. A bracket, a curved waveguide, and a corrugated horn are detachably installed on the connection tray in sequence from outside to inside. The opening of the corrugated horn faces the reflecting surface of the sub-reflector. The connection tray, the main reflector, the curved waveguide, the corrugated horn, and the sub-reflector are coaxially arranged. By providing a through hole in the main reflector and passing through and fixing the bracket, the curved waveguide, the corrugated horn, and the connection tray on the main reflector, the installation structure of the Cassegrain antenna can be simplified, facilitating installation. Moreover, through the mutual cooperation of the connecting parts of each component, the antenna can be made more firm, thus adapting to the application environment of geostationary satellites.

Description

Technical Field

[0001] The present invention belongs to the technical field of antennas, and particularly relates to a dual circularly polarized Cassegrain antenna applied to LEO low-earth orbit satellite communication. Background Art

[0002] Modern low-earth orbit satellites have the characteristics of low equipment complexity, small communication time delay, strong function and anti-destruction ability, high security, strong emergency response and flexibility, high practicality and reliability, short system construction period, relatively small investment, launch and operation costs, etc., and are widely used in fields such as scientific exploration, data communication and message transmission. The demand for low-earth orbit satellite communication terminal antennas with characteristics such as high gain and low elevation angle is increasing day by day.

[0003] The common antennas equipped on low-earth orbit satellites are circularly polarized antennas, which can suppress rain and fog interference and can meet the requirements of geosynchronous orbit satellites. However, due to limitations such as size, structure, and weight, conventional circularly polarized antennas are difficult to adapt to the application conditions of low-earth orbit satellites, thus causing difficulties in data communication. Summary of the Invention

[0004] The purpose of the present invention is to provide a dual circularly polarized Cassegrain antenna applied to LEO low-earth orbit satellite communication. By overall designing each antenna component, the structures of the antenna components are matched and the installation strength is high.

[0005] The present invention adopts the following technical solutions: A dual circularly polarized Cassegrain antenna applied to LEO low-earth orbit satellite communication, including a main reflector. The main reflector is in a parabolic shape, and its inner surface is the main reflecting surface. A sub-reflector is installed on the main reflecting surface through a sub-reflector support. The reflecting surface of the sub-reflector is arranged opposite to the main reflecting surface;

[0006] A through hole is opened at the center of the main reflector. A connection tray is detachably arranged on the outer surface of the main reflector and outside the through hole. The front end of the connection tray is connected to the main reflector, and the rear end is used to connect to an external low-earth orbit satellite turntable;

[0007] A bracket, a corrugated waveguide, and a corrugated horn are detachably installed on the connection tray in sequence from outside to inside. The opening of the corrugated horn faces the reflecting surface of the sub-reflector;

[0008] The connection tray, the main reflector, the corrugated waveguide, the corrugated horn, and the sub-reflector are coaxially arranged;

[0009] Among them, the corrugated waveguide is used to connect to an external receiver / transmitter, so as to send the signal of the transmitter through the corrugated horn, the sub-reflector, and the main reflector in sequence, or forward the signal received through the main reflector, the sub-reflector, and the corrugated horn to the receiver.

[0010] Furthermore, the sub-reflector includes a connecting plate, which is an annular plate. A number of mounting lugs are arranged on the annular plate extending towards the inner space of the ring; among them, the lugs are used to connect with the sub-reflector bracket;

[0011] The rear end of the annular plate is fixedly connected with a reflecting surface, which is a hyperboloid, and the protruding direction faces the main reflector.

[0012] Furthermore, the sub-reflector bracket is rod-shaped, with connecting parts at both ends. One end is connected with the mounting lug through the connecting part, and the other end is connected with the edge of the main reflector;

[0013] The number of sub-reflector brackets is at least three.

[0014] Furthermore, the connecting tray includes an annular plate that fits and connects with the outer surface of the main reflector. An annular tube is fixedly connected to the inner peripheral surface of the annular plate;

[0015] The front end of the annular tube is fixedly connected to the inner peripheral surface of the annular plate, and a bottom plate is arranged at the rear end. The bottom plate is used to connect with the curved waveguide and the external low-earth orbit satellite turntable respectively.

[0016] Furthermore, the bottom plate includes a ring. The outer periphery of the ring is fixedly connected to the rear end of the annular tube through a number of connecting arms;

[0017] A tray is arranged extending inwards from the ring. The tray and the inner wall of the annular tube form a fixing groove, and the fixing groove is used to fixedly install the bracket.

[0018] Furthermore, the bracket includes a bracket top plate and a bracket bottom plate;

[0019] The bracket top plate and the bracket bottom plate are connected by columns;

[0020] The bracket bottom plate is a circular plate, which is used to be placed in the fixing groove and connected with the tray;

[0021] Through holes are provided in the middle of both the bracket bottom plate and the bracket top plate;

[0022] A through hole corresponding to the through hole on the bracket bottom plate is opened in the middle of the tray.

[0023] Furthermore, the curved waveguide includes a connecting bottom plate, which is used to connect with the bracket top plate;

[0024] A first curved waveguide and a second curved waveguide that are symmetrically arranged in space are installed on the connecting bottom plate, and through holes corresponding to the ends of the first curved waveguide and the second curved waveguide are provided on the connecting bottom plate;

[0025] The other ends of the first curved waveguide and the second curved waveguide are both connected to the same connecting top plate.

[0026] Furthermore, the corrugated horn includes a feed source and a horn mouth that are integrally formed;

[0027] The feed is circular tubular, and a circular polarizer is provided at the inner end away from the horn mouth. The circular polarizer is a stepped metal diaphragm and is used to convert the signals passing through the first bent waveguide and the second bent waveguide into circularly polarized signals in different forms;

[0028] A connecting flange is provided at the rear end of the feed, and the connecting flange is used to connect with the connecting top plate.

[0029] The beneficial effects of the present invention are as follows: By opening through holes in the main reflector and passing through and fixing the bracket, the corrugated horn of the bent waveguide and the connecting tray on the main reflector, the installation structure of the Cassegrain antenna can be simplified, facilitating installation. And through the mutual cooperation of the connecting parts of each component, the antenna can be made more firm, and thus it is suitable for the application environment of low-earth orbit satellites. Description of the Drawings

[0030] Figure 1 It is a schematic structural diagram of a dual-circularly polarized Cassegrain antenna applied to LEO low-earth orbit satellite communication according to an embodiment of the present invention;

[0031] Figure 2 is Figure 1 a schematic structural diagram from another perspective;

[0032] Figure 3 It is a schematic structural diagram of the connecting tray in an embodiment of the present invention;

[0033] Figure 4 It is a schematic structural diagram of the sub-reflector in an embodiment of the present invention;

[0034] Figure 5 It is a schematic diagram of the mechanism of the corrugated horn in an embodiment of the present invention;

[0035] Figure 6 It is another perspective schematic diagram of the mechanism of the corrugated horn in an embodiment of the present invention;

[0036] Figure 7 It is a schematic structural diagram of the bent waveguide in an embodiment of the present invention;

[0037] Figure 8 It is a schematic structural diagram of the bracket in an embodiment of the present invention.

[0038] Wherein: 10. Main reflector; 11. Honeycomb sandwich;

[0039] 20. Connecting tray; 21. Circular ring plate; 22. Bottom plate; 23. Circular ring tube;

[0040] 211. Main reflector fixing hole; 221. Circular ring; 222. Reserved hole; 223. Support plate; 224. Connecting arm;

[0041] 30. Bracket; 31. Bracket top plate; 32. Bracket bottom plate; 33. Column

[0042] 40. Bent waveguide; 41. First bent waveguide; 42. Second bent waveguide; 43. Connection bottom plate; 44. Connection top plate

[0043] 50. Corrugated horn; 51. Circular polarizer; 52. Horn aperture; 53. Connection flange; 54. Feed source

[0044] 60. Sub-reflector support

[0045] 70. Sub-reflector; 71. Connection plate; 72. Reflective surface; 73. Mounting hole; 74. Mounting ear plate Detailed implementation mode

[0046] The present invention will be described in detail below in conjunction with the accompanying drawings and the specific implementation mode.

[0047] The present invention discloses a dual-circular polarization Cassegrain antenna applied to LEO low-earth orbit satellite communication. As shown in Figure 1 , Figure 2 , it includes a main reflector 10. The main reflector 10 is spherical, and its inner surface is the main reflective surface. A sub-reflector 70 is installed on the main reflective surface through a sub-reflector support 60. The reflective surface of the sub-reflector 70 is arranged opposite to the main reflective surface; a through hole is opened at the central part of the main reflector 10, and a connection tray 20 is detachably arranged on the outer surface of the main reflector 10 and outside the through hole. The front end of the connection tray 20 is connected to the main reflector 10, and the rear end is used to connect to an external low-earth orbit satellite turntable; a bracket 30, a bent waveguide 40, and a corrugated horn 50 are detachably installed on the connection tray 20 in sequence from outside to inside. The opening of the corrugated horn 50 faces the reflective surface of the sub-reflector 70; the connection tray 20, the main reflector 10, the bent waveguide 40, the corrugated horn 50, and the sub-reflector 70 are coaxially arranged; wherein, the bent waveguide 40 is used to connect to an external receiver / transmitter to transmit the signal of the transmitter through the corrugated horn 50, the sub-reflector 70, and the main reflector 10 in sequence, or to forward the signal received through the main reflector 10, the sub-reflector 70, and the corrugated horn 50 to the receiver.

[0048] By opening a through hole in the main reflector and passing through and fixing the bracket, the bent waveguide, the corrugated horn, and the connection tray on the main reflector, the present invention can simplify the installation structure of the Cassegrain antenna, facilitate installation, and through the cooperation of the connecting parts of each component, the antenna can be made more firm, and thus can be used in the application environment of geostationary satellites.

[0049] In an embodiment of the present invention, the main reflector 10 is made of carbon fiber material, and the remaining components are all made of aluminum material, which can reduce the overall weight of the antenna and does not interfere with the signal transmission. Specifically, the main reflector 10 includes a main reflecting surface on its inner surface and an outer surface, and a honeycomb sandwich 11 is provided between the inner surface and the outer surface. Aluminum honeycomb can be selected as the sandwich material for the honeycomb sandwich 11. Through the selection and use of carbon fiber material, the structural performance of the reflector can be further improved, and the influence on the antenna performance in the low-earth orbit environment can be reduced.

[0050] In an embodiment of the present invention, as Figure 4 shown, the sub-reflector 70 includes a connecting plate 71. The connecting plate 71 is an annular plate, and several mounting ear plates 74 extend into the inner space of the ring. Among them, the ear plates 74 are used to connect with the sub-reflector bracket 60; the rear end of the annular plate is fixedly connected with a reflecting surface 72. The reflecting surface 72 is a spherical surface, and the protruding direction faces the main reflecting surface. Specifically, in this embodiment, the number of the mounting ear plates 74 is four, making the fixation more firm. Moreover, the sub-reflector bracket 60 and the mounting ear plate 74 are connected by bolts. The bolts pass through one end of the sub-reflector bracket 60 and pass out from the other end of the mounting ear plate 74, increasing the connection length, improving the structural strength, and greatly enhancing the adaptability of the antenna in the low-earth orbit environment.

[0051] In addition, the protruding arc surface of the reflecting surface 72 faces the main reflector 10, and several mounting holes 73 are provided on the concave arc surface. Through these mounting holes, the external cube mirror can be installed and fixed, thereby improving the coincidence degree of the optical and electrical axes of the system.

[0052] As a specific implementation manner, the sub-reflector bracket 60 is rod-shaped, with fixed ear plates at both ends. One end is connected to the mounting ear plate 74 through a connecting part, and the other end is connected to the edge of the main reflector; the number of the sub-reflector brackets 60 is at least three. The number of the sub-reflector brackets 60 should correspond to the number of the mounting ear plates 74, and they are evenly spaced and fixed on the edge of the main reflector 10 to avoid signal interference.

[0053] In an embodiment of the present invention, as Figure 3 shown, the connecting tray 20 includes a circular ring plate 21 that fits and connects with the outer surface of the main reflector 10. An annular tube 23 is fixedly connected to the inner peripheral surface of the circular ring plate 21. To ensure the tight fit between the circular ring plate 21 and the outer surface of the main reflector 10, the circular ring plate 21 has a certain curvature, and the specific curvature is adapted to the curvature of the main reflector 10. On the circular ring plate 21, several main reflector fixing holes 211 are circumferentially spaced, and fixing holes are also provided at the corresponding positions on the main reflector 10. Then, the circular ring plate 21 and the main reflector 10 can be tightly connected and fixed by bolts passing through the two fixing holes, increasing the connection strength, adapting to the environment of low-earth orbit satellites, and preventing the influence of impact or other forces.

[0054] In addition, the front end of the circular tube 23 is fixedly connected to the inner circumferential surface of the circular plate 21, and a bottom plate 22 is provided at the rear end. The bottom plate 22 is used to be connected to the bent waveguide 40 and the external low-orbit satellite turntable respectively. The bottom plate 22 includes a ring 221, and the outer circumference of the ring 221 is fixedly connected to the rear end of the circular tube 23 through a plurality of connecting arms 224; a support plate 223 extends inward from the ring 221, and the support plate 223 and the inner wall of the circular tube 23 form a fixing groove for fixedly installing the bracket 30. In this embodiment, through the mutual cooperation of the fixing groove and the mounting bracket 30, combined with the fixing of bolts, the connection strength between the two is further increased. A reserved hole 222 having the same shape and size as the bracket bottom plate 32 is provided in the middle of the bottom plate 22. On the one hand, it facilitates the passing of the external waveguide, and on the other hand, it can also reduce the overall weight of the antenna, thereby reducing the energy consumption of the low-orbit satellite.

[0055] In an embodiment of the present invention, as Figure 8 shown, the bracket 30 includes a bracket top plate 31 and a bracket bottom plate 32; the bracket top plate 31 and the bracket bottom plate 32 are connected by columns 33; in this way, the bracket 30 forms a frame structure, which can reduce the overall mass of the antenna while ensuring the connection strength, and can reduce the energy consumption of the low-orbit satellite. The bracket bottom plate 32 is a circular plate for placing in the fixing groove and connecting to the support plate 223; through holes are provided in the middle of both the bracket bottom plate 32 and the bracket top plate 31; a through hole corresponding to the position of the through hole on the bracket bottom plate 32 is opened in the middle of the support plate 223. Through the setting of multiple through holes, when the external waveguide is connected to the bent waveguide 40, it can provide a connection space and an operation space during connection for the external waveguide, facilitating installation.

[0056] In an embodiment of the present invention, as Figure 7 shown, the bent waveguide 40 includes a connection bottom plate 43 for connecting to the bracket top plate 31; the connection bottom plate corresponds to the shape of the bracket top plate 31, and through holes are opened in both, and the connection type is a flange connection, further increasing the connection strength. A first bent waveguide 41 and a second bent waveguide 42 are symmetrically arranged in space on the connection bottom plate 43, and through holes corresponding to the ends of the first bent waveguide 41 and the second bent waveguide 42 are provided on the connection bottom plate 43; the other ends of the first bent waveguide 41 and the second bent waveguide 42 are both connected to the same connection top plate 44. Further, when the external waveguide is connected to the first bent waveguide 41 and the second bent waveguide 42, the connection part of the external waveguide can be connected to the connection bottom plate 43 by bolts to prevent the external waveguide from falling off between the first bent waveguide 41 or the second bent waveguide 42.

[0057] As Figure 5 、 Figure 6As shown, the corrugated horn 50 includes an integrally formed feed 54 and a horn mouth 52. The feed 54 is circular tubular, and a circular polarizer 51 is provided at the inner end thereof away from the horn mouth 52. The circular polarizer 51 is a stepped metal diaphragm and is used to convert the signals passing through the first bent waveguide 41 and the second bent waveguide 42 into different forms of circularly polarized signals to meet the communication requirements of low-earth orbit satellites. A connection flange 53 is provided at the rear end of the feed 54, and the connection flange 53 is used to connect to the connection top plate 44.

[0058] In the embodiment of the present invention, the connection between each component adopts a flange connection method, which can effectively increase the connection strength between each component. The Cassegrain antenna composed of a main reflector, a sub-reflector, a corrugated horn, a circular polarizer, a bracket, etc. has the function of receiving and transmitting circularly polarized electromagnetic wave signals. High thermal stability carbon fiber composite materials are selected for each part of the main reflector, and the sub-reflector materials are all made of aluminum through precision machining. Since both aluminum and carbon fiber have good physical properties, the overall mass of the antenna is less than or equal to 650 g. Therefore, in the spaceborne environment, the overall stability of the antenna system performance can be satisfied.

Claims

1. A dual-circularly polarized Cassegrain antenna applied to LEO low-earth orbit satellite communication, characterized in that, it includes a main reflector (10), the main reflector (10) is in a parabolic shape, its inner surface is the main reflecting surface, and a sub-reflector (70) is installed on the main reflecting surface through a sub-reflector support (60), and the reflecting surface of the sub-reflector (70) is arranged opposite to the main reflecting surface; the main reflector (10) is made of carbon fiber material; a through hole is opened at the center of the main reflector (10), and a connection tray (20) is detachably arranged on the outer surface of the main reflector (10) and outside the through hole. The front end of the connection tray (20) is connected to the main reflector (10), and the rear end is used to connect to an external low-earth orbit satellite turntable; a bracket (30), a curved waveguide (40) and a corrugated horn (50) are detachably installed on the connection tray (20) from outside to inside in sequence, and the opening of the corrugated horn (50) faces the reflecting surface of the sub-reflector (70); the connection tray (20), the main reflector (10), the curved waveguide (40), the corrugated horn (50) and the sub-reflector (70) are coaxially arranged; wherein, the curved waveguide (40) is used to connect to an external receiver / transmitter, so as to send the signal of the transmitter through the corrugated horn (50), the sub-reflector (70) and the main reflector (10) in sequence, or forward the signal received through the main reflector (10), the sub-reflector (70) and the corrugated horn (50) to the receiver; the sub-reflector (70) includes a connecting plate (71), the connecting plate (71) is an annular plate, and a plurality of mounting ear plates (74) extend into the inner space of the annular plate; wherein, the mounting ear plates (74) are used to connect to the sub-reflector support (60); the rear end of the annular plate is fixedly connected with a reflecting surface (72), the reflecting surface (72) is a hyperboloid, and the protruding direction faces the main reflecting surface; the curved waveguide (40) includes a connecting bottom plate (43), and the connecting bottom plate (43) is used to connect to the bracket top plate (31) of the bracket (30); a first curved waveguide (41) and a second curved waveguide (42) which are symmetrically arranged in space are installed on the connecting bottom plate (43), and through holes corresponding to the ends of the first curved waveguide (41) and the second curved waveguide (42) are arranged on the connecting bottom plate (43); the other ends of the first curved waveguide (41) and the second curved waveguide (42) are both connected to the same connecting top plate (44).

2. A dual-circularly polarized Cassegrain antenna applied to LEO low-earth orbit satellite communication according to claim 1, characterized in that, the sub-reflector support (60) is rod-shaped, with fixed ear plates at both ends, one end of which is connected to the mounting ear plate (74) through the fixed ear plate, and the other end is connected to the edge of the main reflector; the number of the sub-reflector supports (60) is at least three.

3. A dual-circularly polarized Cassegrain antenna applied to LEO low-earth orbit satellite communication according to claim 1 or 2, characterized in that, The connecting tray (20) includes an annular plate (21) which is fitted and connected to the outer surface of the main reflector (10), and an annular tube (23) is fixedly connected to the inner peripheral surface of the annular plate (21); The front end of the annular tube (23) is fixedly connected to the inner peripheral surface of the annular plate (21), and a bottom plate (22) is arranged at the rear end. The bottom plate (22) is used to be respectively connected to the bent waveguide (40) and an external low-earth orbit satellite turntable.

4. A dual-circular polarization Cassegrain antenna applied to LEO low-earth orbit satellite communication according to claim 3, characterized in that, The bottom plate (22) includes an annulus (221), and the outer periphery of the annulus (221) is fixedly connected to the rear end of the annular tube (23) through a plurality of connecting arms (224); A support plate (223) extends inwards from the annulus (221), and a fixing groove is formed between the support plate (223) and the inner wall of the annular tube (23). The fixing groove is used for fixedly installing the bracket (30).

5. A dual-circular polarization Cassegrain antenna applied to LEO low-earth orbit satellite communication according to claim 4, characterized in that, The bracket (30) includes a bracket top plate (31) and a bracket bottom plate (32); The bracket top plate (31) and the bracket bottom plate (32) are connected by columns (33); The bracket bottom plate (32) is a circular plate, and the circular plate is used to be placed in the fixing groove and connected to the support plate (223); Through holes are provided in the middle of both the bracket bottom plate (32) and the bracket top plate (31); A through hole corresponding to the position of the through hole on the bracket bottom plate (32) is formed in the middle of the support plate (223).

6. A dual-circular polarization Cassegrain antenna applied to LEO low-earth orbit satellite communication according to claim 5, characterized in that, The corrugated horn (50) includes a feed source (54) and a horn mouth (52) which are integrally formed; The feed source (54) is a circular tube, and a circular polarizer (51) is arranged at the inner end of the feed source (54) far away from the horn mouth (52). The circular polarizer (51) is a stepped metal diaphragm and is used to convert the signals passing through the first bent waveguide (41) and the second bent waveguide (42) into different forms of circular polarization signals respectively; A connecting flange (53) is arranged at the rear end of the feed source (54), and the connecting flange (53) is used to be connected to the connecting top plate (44).

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