A frequency selective surface sub-reflector high-gain multi-band reflector antenna

Abstract

The present application relates to satellite communication antenna technical field, disclose a kind of frequency selective surface deputy high-gain multi-band reflector antenna, comprising: main reflector;Frequency selective surface deputy reflector, etching periodic arrangement of slot structure on the base of deputy reflector and form, the transmission characteristics of low frequency band electromagnetic wave and the total reflection characteristics of high frequency band electromagnetic wave;Deputy support rod, for fixing and supporting frequency selective surface deputy reflector on main reflector;LS broadband feed source, arranged at the top of frequency selective surface deputy reflector, its polarization direction is perpendicular to the long side direction of the slot structure;X / K / EHF feed source system, arranged in the space between main reflector and frequency selective surface deputy reflector, its polarization direction is parallel to the long side direction of the slot structure;Frequency selective surface deputy reflector makes antenna present single reflector radiation form when working in low frequency band, present double reflector radiation form when working in high frequency band, realizes the high efficiency radiation of each frequency band.

Description

Technical Field

[0001] This invention relates to the field of satellite communication antenna technology, and in particular to a frequency-selective surface-mount high-gain multi-band reflector antenna. Background Technology

[0002] Reflector antennas are widely used in satellite communications, deep space exploration, and ground receiving systems due to their advantages such as high gain, simple structure, and reliable operation. In multi-band shared antenna applications, maintaining high radiation efficiency across different frequency bands is a key challenge in antenna design.

[0003] Traditional single-reflector antennas have a simple structure, with the feed located in front of the main reflector. They are suitable for applications where the feed size is small, obstruction is acceptable, and structural requirements are simple. However, single-reflector antennas have a large longitudinal envelope. When complex feed networks with multiple frequency bands and channels are required, the feed and feed network will significantly increase the obstruction to the main reflector, and the feed network layout will be difficult, which is not conducive to system integration.

[0004] Dual-reflector antennas (such as Cassegrain or Gregorian antennas) effectively shorten the antenna's longitudinal dimension through secondary reflection from the sub-reflector, and place the feed and feed network within the space between the main and sub-reflectors, thus providing ample space for complex feed network layouts. However, dual-reflector antennas require the illumination taper of the feed to match the edge level of the sub-reflector to achieve high-efficiency radiation. When operating at lower frequencies (such as the L / S band), the feed size increases significantly with increasing wavelength, making it difficult to simultaneously meet the requirements of low obstruction, low taper, and high efficiency within the limited internal space of the reflector. This results in low-frequency efficiency typically being only 10%–20%, far lower than high-frequency performance.

[0005] Furthermore, in the design of multi-band shared antennas, the electromagnetic characteristics requirements of the subreflector for different frequency bands are often contradictory: high-frequency bands require the subreflector to have good reflection performance, while low-frequency bands prefer the subreflector to transmit electromagnetic waves as much as possible to reduce obstruction and energy loss. Traditional metallic subreflectors cannot simultaneously meet these requirements, making it difficult for multi-band antennas to achieve efficient radiation in all frequency bands.

[0006] Therefore, there is an urgent need for a sub-reflector structure that can adaptively change its electromagnetic properties at different frequency bands, so as to balance high transmission in the low frequency band and high reflection in the high frequency band, thereby breaking through the performance bottleneck of traditional reflector antennas in multi-frequency band collaborative operation. Summary of the Invention

[0007] The purpose of this invention is to overcome the shortcomings of the prior art and provide a frequency-selective surface-reflecting high-gain multi-band reflector antenna. By designing a sub-reflector with frequency selectivity, low-frequency electromagnetic waves are transmitted to form single-reflector radiation, and high-frequency electromagnetic waves are totally reflected to form double-reflector radiation. This simultaneously solves the problem of low efficiency caused by the large feed size in the low-frequency band and the requirement for complex feed grid layout in the high-frequency band, thus achieving high-efficiency radiation in each frequency band.

[0008] To achieve the above objectives, the present invention provides a frequency-selective surface-mount high-gain multi-band reflector antenna, comprising: Main reflecting surface; A frequency selective surface sub-reflector is formed by etching periodically arranged slit structures on a sub-reflector substrate to achieve transmission characteristics for low-frequency electromagnetic waves and total reflection characteristics for high-frequency electromagnetic waves. A secondary reflector support rod is used to fix and support the frequency selective surface secondary reflector on the main reflector surface; An LS broadband feed is positioned on top of the frequency-selective surface subreflector, with its polarization direction perpendicular to the long side of the slot structure; and The X / K / EHF feed system is arranged in the space between the main reflector and the frequency selective surface sub-reflector, and its polarization direction is parallel to the long side of the slot structure. The frequency-selective surface sub-reflector causes the antenna to radiate in a single-reflector mode when operating in the low-frequency band, and in a double-reflector mode when operating in the high-frequency band.

[0009] Furthermore, the main reflecting surface is a parabolic surface of revolution.

[0010] Furthermore, the frequency selection surface sub-reflector is a hyperboloid structure.

[0011] Preferably, the periodically arranged slit structure is etched on the hyperboloid of revolution, and the geometric parameters of the slit structure are consistent with the surface profile of the hyperboloid of revolution.

[0012] Furthermore, the substrate of the frequency selective surface sub-reflector is made of fiberglass, and a metal layer is plated on the side of the substrate facing the main reflector to achieve conductivity and reduce thermal deformation.

[0013] Furthermore, there are four secondary reflector support rods. The main body of each support rod is made of carbon fiber material with an elliptical cross section and titanium alloy connectors at both ends. The frequency selective surface sub-reflector is fixedly connected to the main reflector through the four secondary reflector support rods.

[0014] Furthermore, the LS broadband feed is composed of a ridge waveguide shaped horn antenna, and the phase center of the LS broadband feed is located at the hyperboloid focal point of the sub-reflector of the frequency selective surface.

[0015] Furthermore, the X / K / EHF feed system includes an X / K / EHF composite feed, an X sum and difference network, a K coupling network, and an EHF network. The X / K / EHF composite feed is an integrated fabrication structure, with its periphery composed of four identical square horns and a round horn embedded in the middle. The four square horns are connected to the X sum and difference network via waveguides, and the embedded circular horn is connected to the K coupling network and the EHF network via waveguides respectively.

[0016] Preferably, the X / K / EHF composite feed is positioned at the focal point between the primary reflector and the frequency-selective sub-reflector.

[0017] More preferably, the frequency-selective surface sub-reflector exhibits wave-transmitting characteristics to electromagnetic waves in the low-frequency (LS) band, making the antenna equivalent to a single-reflector antenna without sub-reflector obstruction when operating in the LS band. The frequency-selective surface sub-reflector exhibits electric wall characteristics on electromagnetic waves in the high-frequency X-band, K-band, and EHF-band, causing the incident wave to be totally reflected. Thus, the antenna achieves a dual-reflector antenna form when operating in the high-frequency band.

[0018] Compared with the prior art, the beneficial effects of the present invention are: This invention achieves single-reflector radiation in the low-frequency band (LS) through a sub-reflector, and achieves double-reflector radiation in the high-frequency band (X / K / EHF) through reflection. The measured efficiency of each frequency band reaches 55%, far exceeding the traditional solution (LS band is only 10%~20%). This invention places the LS feed on top of the sub-reflector, so that electromagnetic waves are transmitted and radiated by the main reflector, avoiding the stringent requirement of tapering the low-frequency feed on the dual reflector surfaces, and significantly improving low-frequency efficiency. In this invention, the high-frequency feed and complex feed network are arranged between the main and secondary inverters, utilizing the space behind the dual inverters to facilitate the integration of sum and difference networks, coupling networks, etc. The secondary reflector of this invention uses a fiberglass substrate plated with metal, resulting in minimal thermal deformation; the support rod is made of carbon fiber + titanium alloy, which is lightweight and has high rigidity. The X / K / EHF composite feed of this invention integrates a square horn and a round horn, reducing size and weight and facilitating engineering applications. Attached Figure Description

[0019] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used in conjunction with embodiments of the invention to explain the invention and do not constitute a limitation thereof. In the drawings: Figure 1 This is a schematic diagram of a frequency-selective surface-mount high-gain multi-band reflector antenna structure according to the present invention; Figure 2 This is a detailed structural diagram of a frequency-selective surface sub-reflector according to the present invention; Figure 3 This is a schematic diagram of an X / K / EHF feed system according to the present invention; Figure 4 This is a schematic diagram of the measured radiation direction of L-band gain according to the present invention; Figure 5 This is a schematic diagram of the measured radiation direction of S-band gain according to the present invention; Figure 6 This is a schematic diagram of the measured radiation direction of X-band gain according to the present invention; Figure 7 This is a schematic diagram of the measured radiation direction of K-band gain according to the present invention; Figure 8 This is a schematic diagram of the measured radiation direction of EHF band gain according to the present invention.

[0020] Figure Labels 1: Primary reflector; 2: Frequency-selective secondary reflector; 21: Periodically arranged slit structures; 3: Secondary anti-support rod; 4: LS broadband feed; 5: X / K / EHF feed system; 51: X / K / EHF composite feed; 52: X sum and difference network; 53: K coupled network; 54: EHF network. Detailed Implementation

[0021] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0022] The specific embodiments of the present invention will be described below with reference to the accompanying drawings and examples. Example 1

[0023] Please see Figure 1 The frequency-selective surface-mount high-gain multi-band reflector antenna provided in this embodiment includes: Main reflecting surface (1); Frequency selective surface sub-reflector (2), which is formed by etching periodically arranged slit structures (21) on the sub-reflector substrate, to achieve transmission characteristics for low-frequency electromagnetic waves and total reflection characteristics for high-frequency electromagnetic waves. The secondary reflector (3) is used to fix and support the frequency selective surface secondary reflector (2) on the main reflector (1); An LS broadband feed (4) is arranged on top of the frequency-selective surface sub-reflector (2), and its polarization direction is perpendicular to the long side direction of the slot structure; and The X / K / EHF feed system (5) is arranged in the space between the main reflector (1) and the frequency selective surface sub-reflector (2), and its polarization direction is parallel to the long side direction of the slot structure. The frequency-selective surface sub-reflector (2) makes the antenna exhibit a single-reflector radiation form when operating in the low-frequency band and a double-reflector radiation form when operating in the high-frequency band.

[0024] The main reflector (1) is a parabolic surface of revolution; the frequency-selective sub-reflector (2) is a hyperboloid of revolution.

[0025] The periodically arranged slit structure (21) is etched on the hyperboloid of revolution, and the geometric parameters of the slit structure are consistent with the surface profile of the hyperboloid of revolution.

[0026] The substrate of the frequency selective surface sub-reflector (2) is made of fiberglass, and a metal layer is plated on the side of the substrate facing the main reflector to achieve conductivity and reduce thermal deformation.

[0027] The number of the secondary reflector support rods (3) is four. The main body of each support rod is made of carbon fiber material with an elliptical cross section and titanium alloy joints at both ends. The frequency selective surface sub-reflector (2) is fixedly connected to the main reflector (1) through the four secondary reflector support rods (3).

[0028] The LS broadband feed (4) is composed of a ridge waveguide shaped horn antenna, and the phase center of the LS broadband feed (4) is located at the hyperboloid focal point of the frequency selective surface sub-reflector (2).

[0029] The X / K / EHF feed system (5) includes an X / K / EHF composite feed (51), an X sum and difference network (52), a K coupling network (53), and an EHF network (54). The X / K / EHF composite feed (5) is an integrated structure, with its periphery composed of four identical square horns and a round horn embedded in the middle. The four square horns are connected to the X sum and difference network (52) via waveguides, and the embedded circular horn is connected to the K coupling network (53) and the EHF network (54) via waveguides respectively.

[0030] The X / K / EHF composite feed (5) is located at the focal point between the main reflector (1) and the frequency-selective sub-reflector (2).

[0031] Specifically, the frequency-selective surface sub-reflector exhibits wave transmission characteristics to electromagnetic waves in the low-frequency (LS) band, making the antenna equivalent to a single-reflector antenna without sub-reflector obstruction when operating in the LS band. The frequency-selective surface sub-reflector exhibits electric wall characteristics on electromagnetic waves in the high-frequency X-band, K-band, and EHF-band, causing the incident wave to be totally reflected. Thus, the antenna achieves a dual-reflector antenna form when operating in the high-frequency band.

[0032] Please refer to the above content. Figure 1 The antenna structure of this embodiment includes a main reflector (1), a frequency-selective sub-reflector (2), a sub-reflector support rod (3), an LS broadband feed (4), and an X / K / EHF feed system (5). The main reflector (1) is a paraboloid of revolution with a diameter of [missing information]. mm, focal length is mm, the equation of the generatrix of the parabola is .

[0033] Figure 2 This is a detailed structural diagram of the frequency-selective surface subreflector (2), showing the diameter of the rotating elliptical surface. mm, the equation of the busbar is The frequency selection surface has a periodically arranged slit structure with a slit width of 0.25 mm, a slit length of 280 mm, a slit interval of 5.3 mm, and a total of 49 slits.

[0034] Figure 3 This is a structural diagram of the X / K / EHF feed system (5) of the present invention. Wherein, Figure 4 This is a typical L-band gain simulation radiation pattern; Figure 6 This is a typical X-band low-frequency gain simulation radiation pattern; Figure 7 This is a typical K-band low-frequency gain simulation radiation pattern; Figure 8 This is a typical low-frequency gain simulation radiation pattern in the EHF band. Furthermore, Figure 5 This is a typical measured radiation pattern of S-band gain.

[0035] The experimental results of the frequency-selective surface-mount sub-reflector high-gain multi-band reflector antenna of the present invention show that it can generate high gain in five separate frequency bands: L, S, X, K, and EHF (LS band: 1.5~3.1GHz; X band: 8~10GHz; K band: 17~22GHz; EHF: 40~46GHz). The antenna achieves an axial gain of 24.9 and an efficiency of 55% in the L band; 28.5 and 55% in the S band; 40.7 and 55% in the X band; 46.3 and 55% in the K band; and 54.2 and 55% in the EHF band.

[0036] Analysis of the low-frequency gain shows that the frequency-selective surface-mount antenna exhibits good transmission efficiency in the low-frequency band. Physically, the low-frequency radiation is above the surface-mount antenna, and electrically, it approximates a single-reflector antenna without surface-mount obstruction, effectively improving the low-frequency efficiency. Analysis of the high-frequency gain shows that the frequency-selective surface-mount antenna exhibits good reflection efficiency in the high-frequency band. The high-frequency band is a dual-reflector antenna, and the gaps in the periodic structure do not leak too much energy, ensuring the high efficiency characteristics of the dual reflectors.

[0037] In summary, this invention successfully achieves electromagnetic characteristics of low-frequency (LS) wave transmission and high-frequency (X / K / EHF) total reflection by organically combining a frequency-selective surface sub-reflector with a main reflector, an LS broadband feed, and an X / K / EHF feed system. Experimental results show that the antenna achieves approximately 55% aperture efficiency across the L, S, X, K, and EHF bands, far exceeding the 10%–20% efficiency of traditional multi-band reflector antennas in the low-frequency band. Simultaneously, this structure retains the advantages of a small envelope and large feed grid layout space inherent in dual-reflector antennas, effectively solving the technical challenge of low tapering efficiency caused by large low-frequency feed dimensions. The frequency-selective surface sub-reflector design of this invention is reasonable, the manufacturing process is feasible, the support structure is stable and reliable, and the integrated composite feed system has a high degree of integration. It is suitable for high-orbit satellite multi-band communication and automatic tracking systems and has promising engineering application prospects.

[0038] Finally, it should be noted that the above description is only a preferred embodiment of the present invention, and the scope of protection of the present invention is not limited to the above embodiments. All technical solutions falling within the scope of the present invention's concept are within the scope of protection of the present invention. It should be pointed out that for those skilled in the art, any improvements and modifications made without departing from the principle of the present invention should also be considered within the scope of protection of the present invention.

[0039] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

Claims

1. A frequency-selective surface-mount high-gain multi-band reflector antenna, characterized in that, include: Main reflecting surface; A frequency selective surface sub-reflector is formed by etching periodically arranged slit structures on a sub-reflector substrate to achieve transmission characteristics for low-frequency electromagnetic waves and total reflection characteristics for high-frequency electromagnetic waves. A secondary reflector support rod is used to fix and support the frequency selective surface secondary reflector on the main reflector; The LS broadband feed is arranged on top of the frequency selective surface sub-reflector, and its polarization direction is perpendicular to the long side direction of the slot structure. as well as The X / K / EHF feed system is arranged in the space between the main reflector and the frequency selective surface sub-reflector, and its polarization direction is parallel to the long side of the slot structure. The frequency-selective surface sub-reflector causes the antenna to radiate in a single-reflector mode when operating in the low-frequency band, and in a double-reflector mode when operating in the high-frequency band.

2. The frequency-selective surface-mount high-gain multi-band reflector antenna according to claim 1, characterized in that, The main reflecting surface is a parabolic surface of revolution.

3. The frequency-selective surface-mount high-gain multi-band reflector antenna according to claim 1, characterized in that, The frequency-selective surface sub-reflector is a hyperboloid structure.

4. The frequency-selective surface-mount high-gain multi-band reflector antenna according to claim 3, characterized in that, The periodically arranged slit structure is etched onto the hyperboloid of revolution, and the geometric parameters of the slit structure are consistent with the surface profile of the hyperboloid of revolution.

5. The frequency-selective surface-mount high-gain multi-band reflector antenna according to claim 1, characterized in that, The substrate of the frequency selective surface sub-reflector is made of fiberglass, and a metal layer is plated on the side of the substrate facing the main reflector to achieve conductivity and reduce thermal deformation.

6. The frequency-selective surface-mount high-gain multi-band reflector antenna according to claim 1, characterized in that, The number of secondary reflector support rods is four. The main body of each support rod is made of carbon fiber material with an elliptical cross section and titanium alloy joints at both ends. The frequency selective surface sub-reflector is fixedly connected to the main reflector through the four secondary reflector support rods.

7. The frequency-selective surface-mount high-gain multi-band reflector antenna according to claim 1, characterized in that, The LS broadband feed is composed of a ridge waveguide shaped horn antenna, and the phase center of the LS broadband feed is located at the hyperboloid focal point of the sub-reflector of the frequency selective surface.

8. The frequency-selective surface-mount high-gain multi-band reflector antenna according to claim 1, characterized in that, The X / K / EHF feed system includes an X / K / EHF composite feed, an X sum and difference network, a K coupling network, and an EHF network. The X / K / EHF composite feed is an integrated fabrication structure, with its periphery consisting of four identical square horns and a round horn embedded in the middle. The four square horns are connected to the X sum and difference network via waveguides, and the embedded circular horn is connected to the K coupling network and the EHF network via waveguides respectively.

9. A frequency-selective surface-mount high-gain multi-band reflector antenna according to claim 8, characterized in that, The X / K / EHF composite feed is positioned at the focal point between the primary reflector and the frequency-selective sub-reflector.

10. A frequency-selective surface-mount high-gain multi-band reflector antenna according to claim 8, characterized in that, The frequency-selective surface sub-reflector exhibits wave transmission characteristics to electromagnetic waves in the low-frequency (LS) band, making the antenna equivalent to a single-reflector antenna without sub-reflector obstruction when operating in the LS band. The frequency-selective surface sub-reflector exhibits electric wall characteristics on electromagnetic waves in the high-frequency X-band, K-band, and EHF-band, causing the incident wave to be totally reflected. Thus, the antenna achieves a dual-reflector antenna form when operating in the high-frequency band.

Images