Dual-frequency dual-beam common-aperture antenna

Abstract

The invention relates to the technical field of satellite communication, in particular to a dual-frequency dual-beam common-aperture antenna, which comprises a feed source horn antenna structure, a plane reflective array antenna structure and a VICTS antenna structure which are arranged in sequence, the feed source horn antenna structure radiates ku-band electromagnetic waves towards the plane reflective array antenna structure; the plane reflective array antenna structure reflects ku-frequency-band electromagnetic waves to form ku-frequency-band directional wave beams which are outwards radiated to be connected with a high-orbit satellite; the VICTS antenna structure reflects ku-frequency-band electromagnetic waves, receives external feed signals and generates ka-frequency-band wave beams with variable directions, and the ka-frequency-band wave beams face the plane reflective array antenna structure; and the plane reflective array antenna structure transmits the ka-frequency-band wave beam, so that the ka-frequency-band wave beam generated by the VICTS antenna structure radiates outwards to track a low-orbit satellite. One antenna aperture has a fixed beam of a ku frequency band and a scanning beam of a ka frequency band at the same time, and a high-orbit satellite and a low-orbit satellite can be connected at the same time.

Description

Technical Field

[0001] The present invention relates to the field of satellite communication technology, and in particular to a dual-frequency dual-beam common aperture antenna. Background Art

[0002] Satellite communication is an effective means to make up for the blind spots in earth communication coverage. According to the distance of the satellite orbit from the earth, it can be divided into high-orbit satellites and medium- and low-orbit satellites. Generally speaking, high-orbit satellites refer to geosynchronous orbit satellites. After decades of development, high-orbit satellite communications are now relatively mature and stable. However, due to the small number of high-orbit satellite resources and the large coverage of a single satellite, the communication bandwidth obtained by each user terminal is narrow and the communication rate is not high. Low-orbit satellites are close to the earth and have a small coverage range of a single satellite, which can provide users with high-speed Internet services. In recent years, low-orbit satellites have attracted many countries around the world to compete for construction. Taking Starlink as an example, it can provide high-speed low-orbit satellite Internet services to many users around the world, but some regions have not yet built a relatively complete low-orbit satellite constellation. In this context, due to the high speed and small number of low-orbit satellites, if low-orbit satellite terminals are used for communication, users will face the problems of short communication time and unstable communication.

[0003] Transmission array antennas and reflector array antennas can only be adjusted in the design stage. Once the antenna is designed and processed, the direction of the antenna beam is fixed and cannot be adjusted. The law between the beam direction of each frequency band of the variable inclination continuous transverse slot (VICTS) antenna and the rotation angle of the antenna disk is different. Since the radiation disk is shared, when the rotating disk adjusts the beam direction of one frequency band to a specific direction, the beam direction of another frequency band cannot be adjusted at will.

[0004] The above contents are only used to assist in understanding the technical solution of the present invention and do not constitute an admission that the above contents are prior art. Summary of the invention

[0005] The main purpose of the present invention is to provide a dual-frequency dual-beam common aperture antenna, aiming to solve the technical problem in the prior art that the antenna cannot simultaneously connect to a high-orbit satellite and a low-orbit satellite.

[0006] To achieve the above object, the present invention proposes a dual-frequency dual-beam common aperture antenna, the dual-frequency dual-beam common aperture antenna comprising: a feed horn antenna structure, a planar reflectarray antenna structure and a VICTS antenna structure arranged in sequence from top to bottom; The feed horn antenna structure is used to radiate Ku-band electromagnetic waves toward the planar reflector array antenna structure; The planar reflector array antenna structure is used to reflect the Ku-band electromagnetic waves to form a Ku-band directional beam that radiates outward to connect with the high-orbit satellite; The VICTS antenna structure is used to reflect the ku-band electromagnetic wave, receive an external feeding signal, generate a variable ka-band beam directed toward the planar reflective array antenna structure; The planar reflective array antenna structure is also used to transmit the Ka-band beam, so that the Ka-band beam generated by the VICTS antenna structure radiates outward to track low-orbit satellites.

[0007] Optionally, the planar reflectarray antenna structure comprises: a plurality of planar reflectarray units; Each of the planar reflective array units is arranged on a side close to the feed horn antenna structure; Each of the planar reflection array units is used to adjust the reflection phase of the Ku-band electromagnetic wave incident at the corresponding position according to the arrangement position, so as to form a Ku-band directional beam with a preset fixed direction to radiate outward.

[0008] Optionally, each of the planar reflective array units comprises: a central circular patch, an intermediate circular ring and an outer circular ring; The central circular patch and the outer circular ring of each of the planar reflective array units have the same size; The reflection phase of each of the planar reflection array units is adjusted by setting the size of the middle circular ring of each of the planar reflection array units.

[0009] Optionally, the VICTS antenna structure comprises: a radiation disk, a shielding disk, a feeding disk and a feed source conversion structure arranged in sequence from top to bottom; The feed conversion structure is used to convert the external ka-band electromagnetic wave input through the input port into a ka-band linear feed electromagnetic wave, and couple the linear feed electromagnetic wave to the feed disk; The feeding plate is used to propagate the linear feed source electromagnetic wave to the shielding plate through the internal circular cavity; The shielding plate is used to transmit the linear feed source electromagnetic wave in the ka frequency band to the radiation plate, and reflect the electromagnetic wave in the ku frequency band; The radiation disk is used to radiate the linear feed electromagnetic wave in the Ka frequency band according to the etched gaps.

[0010] Optionally, a plurality of long strip-shaped gaps are etched on the radiation disk; The side of the shielding plate close to the radiation plate is made of metal material, and the side close to the feeding plate is made of non-metal material; A double-ridge waveguide groove is arranged at a position of the shielding plate corresponding to the long strip gap of the radiation plate.

[0011] Optionally, the relative positions of the radiation disk and the shielding disk are fixed; The relative positions of the radiation disk and the feeding disk are rotated along the central axis, and the radiation is directed to a variable Ka-band beam.

[0012] Optionally, the feed plate is further provided with a circular groove and a ball structure; The circular groove is arranged on a side of the feeding plate close to the shielding plate, and the ball structure is arranged inside the circular groove.

[0013] Optionally, the planar reflector array antenna structure is fixed on a first base, and the VICTS antenna structure is fixed on a second base; The relative positions of the first base and the second base are fixed.

[0014] Optionally, the size of the planar reflectarray antenna structure is larger than the size of the VICTS antenna structure; The dual-frequency dual-beam common aperture antenna is also provided with a metal structure, which enlarges the size of the VICTS antenna structure to the same size as the planar reflectarray antenna structure.

[0015] In addition, to achieve the above-mentioned purpose, the present invention also provides a satellite communication system, which includes the dual-frequency dual-beam co-aperture antenna as described above.

[0016] The present invention provides a dual-frequency dual-beam common-aperture antenna, which includes: a feed horn antenna structure, a planar reflectarray antenna structure, and a VICTS antenna structure arranged in sequence from top to bottom; the feed horn antenna structure is used to radiate ku-band electromagnetic waves toward the planar reflectarray antenna structure; the planar reflectarray antenna structure is used to reflect the ku-band electromagnetic waves to form a ku-band directional beam that radiates outward to connect to a high-orbit satellite; the VICTS antenna structure is used to reflect the ku-band electromagnetic waves, receive an external feed signal to generate a ka-band beam with variable direction toward the planar reflectarray antenna structure; the planar reflectarray antenna structure is also used to transmit the ka-band beam, so that the ka-band beam generated by the VICTS antenna structure radiates outward to track a low-orbit satellite. The ku-band beam formed by the planar reflectarray antenna structure is a high-gain fixed directional beam, which can be used to connect to a high-orbit satellite. The ka-band beam formed by the VICTS antenna structure can adjust the beam direction by rotating the VICTS antenna disc to track a low-orbit satellite. In this way, one antenna aperture can have a fixed beam and a scanning beam at the same time, and can connect to high-orbit satellites and low-orbit satellites at the same time. The structure is relatively simple, practical and has great application potential. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying creative work.

[0018] Figure 1 It is a structural schematic diagram of a first embodiment of a dual-frequency dual-beam common aperture antenna of the present invention; Figure 2 It is a schematic diagram of the structure explosion of the second embodiment of the dual-frequency dual-beam common aperture antenna of the present invention; Figure 3 It is a structural schematic diagram of a planar reflectarray antenna structure in the second embodiment of the dual-frequency dual-beam common aperture antenna of the present invention; Figure 4 It is a partial schematic diagram of the VICTS antenna structure in the second embodiment of the dual-frequency dual-beam common aperture antenna of the present invention; Figure 5 It is a simulation schematic diagram of the antenna Ku band in the second embodiment of the dual-frequency dual-beam common aperture antenna of the present invention; Figure 6 It is a simulation schematic diagram of the antenna Ka-band in the second embodiment of the dual-frequency dual-beam common aperture antenna of the present invention; Figure 7 It is a schematic structural diagram of a third embodiment of a dual-frequency dual-beam common aperture antenna of the present invention; Figure 8 It is a schematic structural diagram of the co-aperture design of three VICTS antenna structures in the third embodiment of the dual-frequency dual-beam co-aperture antenna of the present invention.

[0019] The realization of the purpose, functional features and advantages of the present invention will be further explained in conjunction with embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION

[0020] It should be understood that the specific embodiments described herein are only used to explain the present invention, and are not used to limit the present invention.

[0021] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0022] It should be noted that all directional indications (such as up, down, left, right, front, back, etc.) in the embodiments of the present invention are only used to explain the relative position relationship, movement status, etc. between the components under a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication will also change accordingly.

[0023] In addition, the descriptions of "first", "second", etc. in the present invention are only used for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In addition, the technical solutions between the various embodiments can be combined with each other, but they must be based on the ability of ordinary technicians in the field to implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such a combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0024] The main solution of the embodiment of the present invention is: the dual-frequency dual-beam common-aperture antenna includes: a feed horn antenna structure 1, a planar reflectarray antenna structure 2 and a VICTS antenna structure 3 arranged in sequence from top to bottom; the feed horn antenna structure 1 can be used to radiate ku-band electromagnetic waves toward the planar reflectarray antenna structure 2; the planar reflectarray antenna structure 2 can be used to reflect the ku-band electromagnetic waves to form a ku-band directional beam that radiates outward to connect to high-orbit satellites; the VICTS antenna structure 3 can be used to reflect the ku-band electromagnetic waves, receive external feed signals to generate a variable-direction ka-band beam toward the planar reflectarray antenna structure 2; the planar reflectarray antenna structure 2 can also be used to transmit the ka-band beam, so that the ka-band beam generated by the VICTS antenna structure 3 radiates outward to track low-orbit satellites.

[0025] High-orbit satellite communications are relatively mature and stable. However, due to the small number of high-orbit satellite resources and the large coverage of a single satellite, the communication bandwidth obtained by each user terminal is narrow and the communication rate is not high. Low-orbit satellites are close to the earth and have a small coverage range, so they can provide users with high-speed Internet services. Since low-orbit satellites are fast and few in number, if low-orbit satellite terminals are used for communication, users will face the problems of short communication time and unstable communication. Therefore, it is necessary to design an antenna that can support the connection of high-orbit satellites and low-orbit satellites at the same time, connect to low-orbit satellites when there are low-orbit satellites, and connect to high-orbit satellites when there are no low-orbit satellites, so as to provide users with very stable satellite communication services. For fixed ground communication points, connecting to high-orbit satellites requires fixed antenna beam pointing (high-orbit satellites are in geosynchronous orbit), while connecting to low-orbit satellites requires variable and scannable antenna beam direction to track low-orbit satellites.

[0026] The existing multi-frequency multi-beam reflection / transmission antenna design usually uses a common aperture design, so that one antenna can support multiple frequency bands and multiple beam radiation at the same time. The direction can only be adjusted as needed during the design stage. Once the antenna is designed and processed, the antenna beam is fixed in direction and cannot be adjusted, which greatly limits the use scenarios of the antenna.

[0027] The existing dual-band VICTS antenna design usually supports two frequency bands on one radiating disk to form a co-aperture design. Two types of gaps are etched on a VICTS radiating disk to support the radiation of two frequency bands of beams, covering the two frequency bands of the mobile satellite communication system. The beam pointing of each frequency band of the antenna is different from the rotation angle of the antenna disk. Since the radiating disk is shared, when the disk is rotated to adjust the beam pointing of one frequency band to a specific direction, the beam pointing of the other frequency band cannot be adjusted at will. That is, the beam pointing of the two frequency bands is bound to one radiating disk, and the beam pointing requirements of the two frequency bands cannot be met by rotating the antenna disk at the same time. The so-called dual-band beam can only work in time-sharing.

[0028] There are also designs that combine planar reflectarray antennas and leaky wave antennas to form dual-band beam-scanning antennas. Combining a planar reflectarray antenna with a leaky wave antenna forms a co-aperture design of two antennas, forming dual-frequency dual-beam radiation, and the beam can be scanned. However, the beam scanning achieved by this design, also known as a frequency scanning antenna, means that within the working frequency band supported by the antenna, beams of different frequencies have different beam directions. If you want to change the beam direction of the antenna, you have to switch to a different working frequency. For most wireless communication systems, frequency is a precious resource. Switching frequencies to achieve beam scanning will reduce the frequency utilization efficiency of the system. Therefore, this design has very few application scenarios and is not suitable for use in the field of satellite communications.

[0029] Reference Figure 1 , Figure 1 FIG. 1 is a schematic diagram of the structure of the first embodiment of the dual-frequency dual-beam common aperture antenna of the present invention. Figure 1 As shown, in this embodiment, the feed horn antenna structure 1 can radiate directional Ku-band electromagnetic waves toward the planar reflector array structure 2, and after being reflected by the planar reflector array unit on the planar reflector array structure 2, a high-gain Ku-band directional beam pointing directly upward is formed.

[0030] The design of the planar reflectarray antenna can adopt a scheme in which the feed horn antenna structure 1 is fed directly above the center of the planar reflectarray structure 2 (a forward feeding scheme). The planar reflectarray antenna can also be designed using an offset feeding scheme, that is, the feed antenna is not directly above the reflectarray body, but is offset from the center by a certain angle, and the distribution of the planar reflectarray units (phase distribution) on the planar reflectarray structure 2 is adjusted accordingly. No specific limitation is made in this embodiment.

[0031] The VICTS antenna structure 3 at the bottom layer has an independent ka-band feeding network and a radiation disk. Each layer of the disk of the VICTS antenna structure 3 can rotate around its center in a horizontal plane to form a ka-band beam with variable direction according to the received external feeding signal. The ka-band beam can penetrate the planar reflective array antenna structure 2. In actual applications, there are many solutions for rotating the VICTS antenna disk, such as using a motor to rotate the VICTS disk through a belt, or a motor to rotate the VICTS antenna through a gear, etc. The specific servo rotation solution is not the focus of the present invention, so it is not described in detail here.

[0032] In this embodiment, the dual-frequency dual-beam common aperture antenna includes: a feed horn antenna structure, a planar reflectarray antenna structure and a VICTS antenna structure arranged in sequence from top to bottom; the feed horn antenna structure is used to radiate ku-band electromagnetic waves toward the planar reflectarray antenna structure; the planar reflectarray antenna structure is used to reflect the ku-band electromagnetic waves to form a ku-band directional beam that radiates outward to connect to a high-orbit satellite; the VICTS antenna structure is used to reflect the ku-band electromagnetic waves, receive an external feed signal to generate a ka-band beam with variable direction toward the planar reflectarray antenna structure; the planar reflectarray antenna structure is also used to transmit the ka-band beam, so that the ka-band beam generated by the VICTS antenna structure radiates outward to track a low-orbit satellite. The ku-band beam formed by the planar reflectarray antenna structure is a high-gain fixed directional beam that can be used to connect to a high-orbit satellite. The ka-band beam formed by the VICTS antenna structure can adjust the beam direction by rotating the VICTS antenna disc to track a low-orbit satellite. In this way, one antenna aperture can have a fixed beam and a scanning beam at the same time, and can connect to high-orbit satellites and low-orbit satellites at the same time. The structure is relatively simple, practical and has great application potential.

[0033] Reference Figure 2 , Figure 2 FIG. 1 is a schematic diagram of the structure of the second embodiment of the dual-frequency dual-beam common aperture antenna of the present invention. Figure 2 As shown, in this embodiment, the same or similar contents as those in the first embodiment can be referred to the above description and will not be described in detail later. The dual-frequency dual-beam common aperture antenna includes: the planar reflectarray antenna structure 2 includes: a plurality of planar reflectarray units 21; each of the planar reflectarray units 21 is arranged on a side close to the feed horn antenna structure; each of the planar reflectarray units 21 can be used to adjust the reflection phase of the Ku-band electromagnetic wave incident at the corresponding position according to the arrangement position, so as to form a Ku-band directional beam with a preset fixed direction to radiate outward.

[0034] Reference Figure 3 , Figure 3FIG. 1 is a schematic structural diagram of a planar reflector array antenna structure in a second embodiment of a dual-frequency dual-beam common aperture antenna according to the present invention. Figure 3 As shown, the main body of the planar reflective array antenna structure 2 is a circular PCB structure. The upper layer of the PCB is a planar reflective array unit arranged according to a certain pattern. The unit structure sizes at different positions are different to adjust the reflection phase of the incident electromagnetic wave at different positions to form a high-gain beam. There is no metal on the back of the PCB.

[0035] Furthermore, each of the planar reflective array units 21 comprises: a central circular patch, an intermediate circular ring and an outer circular ring. The central circular patch and the outer circular ring of each planar reflective array unit have the same size; the reflection phase of each planar reflective array unit is adjusted by setting the size of the intermediate circular ring of each planar reflective array unit.

[0036] It should be understood that when the Ku-band electromagnetic wave is irradiated onto the planar reflector array unit 21, the size of the central circular patch and the outer circular ring is kept unchanged, and the reflection phase of the electromagnetic wave can be changed by changing the size of the middle circular ring. The middle circular ring changes from the minimum size (coinciding with the central patch) to the maximum size (coinciding with the outer circular ring), which can change the reflection phase of the electromagnetic wave within the range of 0-360 degrees. The electromagnetic wave emitted from the Ku-band feed horn antenna structure 1 has different propagation paths to each planar reflector array unit on the planar reflector array antenna structure 2, resulting in different propagation phases of the electromagnetic wave. In order to form a high-gain electromagnetic wave beam, the electromagnetic wave needs to propagate in the same phase in the set beam direction. By designing planar reflectarray units of different sizes (adjusting the size of the middle circular ring) at different positions of the planar reflectarray antenna structure 2, it is possible to compensate for the phase difference caused by the path difference when the electromagnetic waves emitted by the feed horn antenna structure 1 irradiate different positions of the planar reflectarray antenna structure 2, so that after the electromagnetic waves are reflected by the planar reflectarray antenna structure 2, the electromagnetic waves at each point can propagate in the same phase toward a specific direction, thereby forming a high-gain antenna beam pointing in a specific direction.

[0037] It should be noted that the planar reflective array unit also has frequency selection characteristics. For the ku band, it is a reflective electromagnetic wave structure, and for the ka band, it is a transmissive electromagnetic wave structure, that is, the ka-band electromagnetic waves emitted by the VCITS antenna structure can penetrate the planar reflective array antenna structure 2 for propagation.

[0038] Furthermore, the VICTS antenna structure 3 includes: a radiation disk 31, a shielding disk 32, a feed disk 33 and a feed conversion structure 34 arranged in sequence from top to bottom. The feed conversion structure 34 can be used to convert the ka-band electromagnetic wave input from the outside through the input port into a linear feed electromagnetic wave in the ka-band, and couple the linear feed electromagnetic wave to the feed disk 33. The feed disk 33 can be used to propagate the linear feed electromagnetic wave to the shielding disk 32 through the internal circular cavity. The shielding disk 32 can be used to transmit the linear feed electromagnetic wave in the ka-band to the radiation disk 31 and reflect the electromagnetic wave in the ku-band. The radiation disk 31 can be used to radiate the linear feed electromagnetic wave in the ka-band according to the etched gap.

[0039] Furthermore, a circular groove and a ball structure are provided on the feed disk; the circular groove is provided on a side of the feed disk close to the shielding disk, and the ball structure is provided inside the circular groove, so as to facilitate relative rotational movement between the feed disk 33 and the radiation disk 31 of the VICTS antenna structure.

[0040] In a traditional planar reflective array antenna, a pure metal layer is placed behind the planar reflective array unit. The planar reflective array unit and the metal layer can be printed on two sides of the same PCB, or the reflective unit array can be printed on one layer of the PCB, with the metal layer maintaining a certain air gap with it. In this embodiment, the planar reflective array unit 21 is backed by a radiation disk 31 of a VICTS antenna structure, rather than a pure metal layer. The planar reflective array unit 21 and the radiation disk 31 of the VICTS antenna structure have a certain air gap. The planar reflective array unit 21, the radiation disk 31 of the VICTS antenna structure, and the shielding disk 32 together form a reflection effect on the Ku-band beam, forming a high-gain reflected beam.

[0041] Reference Figure 4 , Figure 4 FIG. 1 is a partial schematic diagram of the VICTS antenna structure in the second embodiment of the dual-frequency dual-beam common aperture antenna of the present invention. Figure 4 As shown, the radiation disk is etched with a plurality of long strips of slits, the shielding disk is made of metal material on one side close to the radiation disk, and is made of non-metal material on the other side close to the feeding disk; a double-ridge waveguide groove is provided on the shielding disk at the position corresponding to the long strips of slits on the radiation disk.

[0042] Furthermore, the relative positions of the radiation disk 31 and the shielding disk 32 are fixed; the relative positions of the radiation disk 31 and the feeding disk 33 are rotated along the central axis, and the radiation is directed to a variable Ka-band beam.

[0043] It should be noted that the electromagnetic energy in the Ka band is fed in through the feeding port 35, and forms a high-frequency electromagnetic field signal with nearly equal amplitude and phase through the 1-to-N feed source conversion structure 34, which is coupled to the cavity of the feeding disk 33 through the gap at the bottom layer of the feeding disk 33 and propagates. The propagating Ka-band electromagnetic waves can be radiated into the free space through the double-ridge waveguide grooves etched on the shielding disk 32 and the long gaps opened in the radiation disk 31, forming a high-gain Ka-band directional beam. The radiation disk 31 and the shielding disk 32 are fixed together and can rotate together. When the radiation disk 31 rotates a certain angle relative to the feeding disk 33, the electromagnetic beam radiated to the free space will be deflected, forming a Ka-band beam scanning effect.

[0044] It should be understood that a conventional single-band VICTS antenna can radiate electromagnetic waves by etching a long strip of slots on the radiation disk, that is, only the radiation disk 31 is used for radiation. However, the long strip slot structure does not distinguish the working frequency band of the electromagnetic wave. For the present invention, if only the long strip slot is used, the electromagnetic wave emitted by the feed horn antenna structure 1 will pass through the long strip slot on the radiation disk 31 and continue to propagate backward, which will seriously affect the performance of the Ku-band planar reflector array antenna structure 2. The present invention introduces a shielding disk 32 below the radiation disk 31, and etches a double-ridged waveguide groove structure on its upper metal layer, which corresponds to the long strip slot of the radiation disk 31. The double-ridged waveguide groove structure can transmit electromagnetic waves in the ka band and reflect electromagnetic waves in the ku band. The introduction of the shielding disk 32 combined with the radiation disk 31 is a normal wave-transmitting structure for the ka band, and for the ku band, it forms a total reflection effect like a piece of metal.

[0045] Among them, the waveguide is a structure used to directionally guide electromagnetic waves, and is mainly used as a transmission line for microwave frequencies. The waveguide has high-pass and low-resistance characteristics, and the cutoff frequency of the waveguide refers to the lowest frequency at which the waveguide can conduct electromagnetic waves. When the signal frequency is lower than the cutoff frequency, the waveguide cannot transmit electromagnetic waves and can only reflect or absorb electromagnetic waves. The double-ridged waveguide is formed by bending the wide wall of a rectangular waveguide inward, and the cross-sectional size is smaller after bending. For the high-frequency ka-band VICTS antenna, the long strip-shaped gap etched on its radiation disk 31 can propagate a wide range of electromagnetic wave frequencies, and electromagnetic waves in the low-frequency ku-band can also pass through. In order to prevent electromagnetic waves in the ku-band from passing through the gap, a double-ridged waveguide slot structure is etched on the upper metal layer of the shielding disk 32. This double-ridged waveguide slot structure is the cross-sectional shape of the double-ridged waveguide, similar to a dumbbell shape, and its cutoff frequency for transmitting microwaves is the same as that of a double-ridged waveguide transmission structure with the same size. By adjusting and optimizing the specific dimensions, the transmission cutoff frequency of the double-ridge waveguide slot can be made between the low-frequency ku band and the high-frequency ka band, thereby achieving the purpose of propagating ka electromagnetic waves and blocking ku electromagnetic waves.

[0046] Reference Figure 5 and Figure 6 , Figure 5 Schematic diagram of simulation of the antenna Ku band in the second embodiment of the dual-frequency dual-beam common aperture antenna of the present invention. Figure 6 The simulation diagram of the antenna Ka frequency band in the second embodiment of the dual-frequency dual-beam common aperture antenna of the present invention is shown in FIG. The modeling simulation is performed in the electromagnetic field modeling software. The simulation results are shown in FIG. Figure 5 and Figure 6 shown. Figure 5 The simulated directional pattern for the Ku band is the radiation beam of the planar reflector array antenna structure. It can be seen that the planar reflector array antenna forms a high-gain directional beam directly above. Since the double-ridge waveguide slot structure is loaded in the gap of the VICTS antenna structure below, the VICTS antenna has almost no effect on the Ku band antenna. No matter how the VICTS antenna rotates, the high-gain directional beam of the Ku band remains fixed and unchanged. Figure 6 For the ka-band simulation pattern, as the VICTS antenna feed dish and radiation dish rotate relative to different angles, the ka-band radiation beam direction changes, showing a beam scanning effect, which is in line with the working law of the VICTS antenna. It can also be seen that the ku-band planar reflective array antenna has almost no effect on the ka-band VICTS antenna. No matter how the ka-band antenna beam direction changes, the planar reflective array antenna shows an electromagnetic transparent effect on the ka-band antenna beam.

[0047] Reference Figure 7 , Figure 7 FIG. 1 is a schematic diagram of the structure of the third embodiment of the dual-frequency dual-beam common aperture antenna of the present invention. The third embodiment of the dual-frequency dual-beam common aperture antenna of the present invention is proposed based on the above embodiments. Figure 7 As shown, in this embodiment, the same or similar contents as those in the first embodiment and the second embodiment can be referred to the above introduction and will not be described in detail later.

[0048] The effective radiation apertures of the planar reflectarray antenna structure 2 and the VICTS antenna structure 3 may not be exactly the same. For example, since the high-orbit satellite is far away, the planar reflectarray antenna structure connected to the high-orbit usually has a larger aperture, such as a 0.6-meter diameter ku antenna, while the low-orbit satellite is close, and the VICTS antenna structure connected to the low-orbit satellite only needs a small aperture, such as a 0.45-meter diameter ka antenna. When the present embodiment is used for design, it is only necessary to expand the metal part outside the gap of the upper radiation disk of the VICTS antenna to the same size as the planar reflectarray (see Figure 7 Left), or in addition to the VICTS antenna, a metal structure is added (see Figure 7 Right) to reflect Ku-band electromagnetic waves and ensure the performance of the Ku-band planar reflectarray antenna above the VICTS antenna.

[0049] It should be noted that the planar reflectarray antenna structure 2 can be fixed on the radiation disk 31 of the VICTS antenna structure and rotate with the VICTS antenna structure, or it can be fixed on another antenna mounting base and not rotate with the VICTS antenna. Because the ku-band planar reflectarray antenna designed in this embodiment adopts a central forward feeding scheme, the unit distribution on the planar reflectarray antenna structure 2 is central rotationally symmetrical, so the rotation or non-rotation of the planar reflectarray antenna structure 2 has little effect on the reflectarray performance. If the planar reflectarray feed source adopts an offset feeding scheme, the unit distribution on the planar reflectarray antenna structure 2 will not be centrally rotationally symmetrical. At this time, the relative relationship between the planar reflectarray antenna structure 2 and the feed horn antenna structure 1 must remain fixed, that is, the planar reflectarray antenna structure 2 cannot be fixed on the first base of the VICTS antenna structure 3, cannot rotate with the VICTS antenna, and needs to be fixed on a second base outside the VICTS antenna.

[0050] Reference Figure 8 , Figure 8 FIG. 1 is a schematic structural diagram of a dual-frequency dual-beam common aperture antenna according to a third embodiment of the present invention, which includes three VICTS antenna structures with a common aperture design. Figure 8 As shown, multiple small-aperture VICTS antenna structures can be used, and a large-aperture planar reflectarray antenna structure can be used in a co-aperture design to form more radiation beams and frequency bands. For example, three VICTS antenna structures are used in a co-aperture design with a planar reflectarray antenna structure. In the area outside the three VICTS antenna structures, a metal layer structure is added so that the back of the planar reflectarray antenna has a complete metal reflective layer. This schematic antenna scheme can form three scannable VICTS beams and one fixed planar reflectarray beam. Each VICTS antenna works and rotates independently, and can independently track low-orbit satellites, while the large-aperture planar reflectarray antenna is used to align with high-orbit satellite communications. Figure 8 The described antenna can simultaneously aim at one high-orbit satellite and track three low-orbit satellites.

[0051] In addition, in order to achieve the above-mentioned purpose, an embodiment of the present invention also proposes a satellite communication system. Since the satellite communication system includes the above-mentioned dual-frequency dual-beam common-aperture antenna, it at least has all the beneficial effects brought by the technical solutions of the above-mentioned embodiments, which will not be repeated here one by one.

[0052] The above are only preferred embodiments of the present invention, and are not intended to limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made using the contents of the present invention specification and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.

[0053] 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 ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0054] It should be noted that all directional indications (such as up, down, left, right, front, back, etc.) in the embodiments of the present invention are only used to explain the relative position relationship, movement status, etc. between the components under a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication will also change accordingly.

[0055] In addition, the descriptions of "first", "second", etc. in the present invention are only used for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In addition, the technical solutions between the various embodiments can be combined with each other, but they must be based on the ability of ordinary technicians in the field to implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such a combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

Claims

1. A dual-frequency dual-beam common aperture antenna, characterized in that: The dual-frequency dual-beam common aperture antenna comprises: a feed horn antenna structure, a planar reflectarray antenna structure and a VICTS antenna structure arranged in sequence from top to bottom; The feed horn antenna structure is used to radiate Ku-band electromagnetic waves toward the planar reflector array antenna structure; The planar reflector array antenna structure is used to reflect the Ku-band electromagnetic waves to form a Ku-band directional beam that radiates outward to connect with the high-orbit satellite; The VICTS antenna structure is used to reflect the ku-band electromagnetic wave, receive an external feeding signal, generate a variable ka-band beam directed toward the planar reflective array antenna structure; The planar reflective array antenna structure is also used to transmit the Ka-band beam, so that the Ka-band beam generated by the VICTS antenna structure radiates outward to track low-orbit satellites.

2. The dual-frequency dual-beam common aperture antenna according to claim 1, characterized in that: The planar reflectarray antenna structure comprises: a plurality of planar reflectarray units; Each of the planar reflective array units is arranged on a side close to the feed horn antenna structure; Each of the planar reflection array units is used to adjust the reflection phase of the Ku-band electromagnetic wave incident at the corresponding position according to the arrangement position, so as to form a Ku-band directional beam with a preset fixed direction to radiate outward.

3. The dual-frequency dual-beam common aperture antenna according to claim 2, characterized in that: Each of the planar reflective array units comprises: a central circular patch, an intermediate circular ring and an outer circular ring; The central circular patch and the outer circular ring of each of the planar reflective array units have the same size; The reflection phase of each of the planar reflection array units is adjusted by setting the size of the middle circular ring of each of the planar reflection array units.

4. The dual-frequency dual-beam common aperture antenna according to claim 1, characterized in that: The VICTS antenna structure includes: a radiation disk, a shielding disk, a feeding disk and a feed source conversion structure arranged in sequence from top to bottom; The feed conversion structure is used to convert the external ka-band electromagnetic wave input through the input port into a ka-band linear feed electromagnetic wave, and couple the linear feed electromagnetic wave to the feed disk; The feeding plate is used to propagate the linear feed source electromagnetic wave to the shielding plate through the internal circular cavity; The shielding plate is used to transmit the linear feed source electromagnetic wave in the ka frequency band to the radiation plate, and reflect the electromagnetic wave in the ku frequency band; The radiation disk is used to radiate the linear feed electromagnetic wave in the Ka frequency band according to the etched gaps.

5. The dual-frequency dual-beam common aperture antenna according to claim 4, characterized in that: A plurality of long strip-shaped gaps are etched on the radiation disk; The side of the shielding plate close to the radiation plate is made of metal material, and the side close to the feeding plate is made of non-metal material; A double-ridge waveguide groove is arranged at a position of the shielding plate corresponding to the long strip gap of the radiation plate.

6. The dual-frequency dual-beam common aperture antenna according to claim 5, characterized in that: The relative positions of the radiation disk and the shielding disk are fixed; The relative positions of the radiation disk and the feeding disk are rotated along the central axis, and the radiation is directed to a variable Ka-band beam.

7. The dual-frequency dual-beam common aperture antenna according to claim 6, characterized in that: The feed plate is also provided with a circular groove and a ball structure; The circular groove is arranged on a side of the feeding plate close to the shielding plate, and the ball structure is arranged inside the circular groove.

8. The dual-frequency dual-beam common aperture antenna according to claim 1, characterized in that: The planar reflector array antenna structure is fixed on the first base, and the VICTS antenna structure is fixed on the second base; The relative positions of the first base and the second base are fixed.

9. The dual-frequency dual-beam common aperture antenna according to claim 1, characterized in that: The size of the planar reflectarray antenna structure is greater than the size of the VICTS antenna structure; The dual-frequency dual-beam common aperture antenna is also provided with a metal structure, which enlarges the size of the VICTS antenna structure to the same size as the planar reflectarray antenna structure.

10. A communication system, characterized in that: The communication system comprises the dual-frequency dual-beam co-aperture antenna as claimed in any one of claims 1 to 9.

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