Dual-frequency dual-circularly-polarized co-aperture high-gain back cavity antenna and antenna array

Abstract

The application discloses a dual-frequency dual-circularly-polarized shared-aperture high-gain back cavity antenna and an antenna array, and belongs to the technical field of antennas, and aims at solving the problem of how to design a simple-structure dual-frequency dual-circularly-polarized shared-aperture antenna with wide bandwidth and high gain. A rectangular metal back cavity is formed by a metal floor and a metal frame, and an upper end of the rectangular metal back cavity is opened, so that the antenna gain is effectively improved, the antenna has a stable radiation pattern and small back lobe radiation. A high-frequency antenna unit array is arranged in the rectangular metal back cavity, and a low-frequency antenna unit is arranged at a central position in the rectangular metal back cavity; the low-frequency antenna unit is embedded between the high-frequency antenna unit array in a nested shared-aperture mode, and the high-frequency antenna unit array and the low-frequency antenna unit share the metal floor; the high-frequency antenna unit array and the low-frequency antenna unit generate circularly-polarized radiation with different rotation directions, and the polarization between the high-frequency antenna unit array and the low-frequency antenna unit is orthogonal, which is beneficial to reducing mutual coupling and improving the overall performance of the shared-aperture antenna.

Description

Technical Field

[0001] This invention belongs to the field of antenna technology, specifically relating to a dual-frequency dual-circular polarization common aperture high-gain back cavity antenna and antenna array. Background Technology

[0002] Currently, people have increasingly higher requirements for the functionality of communication systems. These systems often employ multiple antennas that independently transmit and receive signals. To make efficient use of system space, multiple antennas often adopt a common-aperture design. Common-aperture antenna technology places multiple antennas within a limited space, reducing mutual coupling between antennas of different frequencies through a reasonable spatial layout, and sharing the same aperture for transmitting and receiving signals. Based on the spatial layout and structural characteristics of common-aperture antennas, common types can be categorized as follows: First, based on a high- and low-frequency sparse array combination structure. This structure is characterized by designing another antenna of a different type in a single antenna element of a sufficiently large size or in a local location within an antenna array. Second, partial structure reuse. While ensuring the normal operation of the high-frequency antenna, the entire structure is used as a low-frequency radiating element to radiate low-frequency electromagnetic waves. This design structure achieves high aperture efficiency through radiator reuse. Third, based on a filtering structure. A filtering structure is inserted between the high- and low-frequency antennas to improve the isolation between them and ensure good independent operating performance. The fourth type is based on an interleaved structure, which commonly has two design approaches: one is a windowed design approach, which allows electromagnetic waves radiated by the high-frequency antenna to pass through by opening a window on the low-frequency antenna, without affecting the radiation characteristics of the low-frequency antenna; the other is a nested design approach, which embeds the low-frequency antenna into the array gaps of the high-frequency antenna and achieves good performance of each antenna through appropriate layout optimization.

[0003] For certain specific applications, such as satellite-to-ground communication and inter-satellite communication, circularly polarized antennas are mostly used. Circularly polarized antennas are generally more complex to implement than linearly polarized antennas, and the design difficulty of co-aperture circularly polarized antennas exceeds that of dual-linearly polarized co-aperture and linear / circularly polarized co-aperture antennas. Most reported co-aperture antennas are dual-linear or linear / circular, while most reported dual-circularly polarized co-aperture antennas have narrow bandwidths for both antennas, or one wide and one narrow bandwidth, and are structurally complex with low gain. Summary of the Invention

[0004] The technical problem to be solved by this invention is how to design a dual-frequency dual-circularly polarized common-aperture antenna with a simple structure, wide bandwidth, and high gain.

[0005] The present invention solves the above-mentioned technical problems through the following technical solutions: A dual-frequency dual-circularly polarized common-aperture high-gain back cavity antenna includes: a high-frequency antenna element array, a low-frequency antenna element (2), and a rectangular metal back cavity (3); the rectangular metal back cavity (3) includes: a metal ground plane (31) and a metal frame (32), the metal ground plane (31) and the metal frame (32) forming a closed rectangular metal cavity with an open top; the high-frequency antenna element array is disposed in the rectangular metal back cavity (3), the low-frequency antenna element (2) is disposed at the center position in the rectangular metal back cavity (3), the low-frequency antenna element (2) is embedded between the high-frequency antenna element array in a nested common-aperture manner, and the high-frequency antenna element array and the low-frequency antenna element (2) share the metal ground plane (31); the high-frequency antenna element array and the low-frequency antenna element (2) respectively generate circularly polarized radiation with different rotation directions, and the polarization between the high-frequency antenna element array and the low-frequency antenna element (2) is orthogonal.

[0006] Furthermore, the high-frequency antenna unit array consists of 4 high-frequency antenna units (1), and the projection of the 4 high-frequency antenna units (1) into a square array of two rows and two columns on the metal floor (31) is centrally symmetrical about the center point of the metal floor (31).

[0007] Further, the high-frequency antenna unit (1) includes: a U-shaped metal patch (11), a high-frequency coaxial feed structure (12), and a first grounding metal post (13); the U-shaped metal patch (11) is arranged parallel above the metal floor (31), the high-frequency coaxial feed structure (12) is arranged vertically on the metal floor (31), one end of the high-frequency coaxial feed structure (12) is connected to the U-shaped metal patch (11), and the other end of the high-frequency coaxial feed structure (12) passes through the metal floor (31); the first grounding metal post (13) is arranged vertically on the metal floor (31), one end of the first grounding metal post (13) is connected to the U-shaped metal patch (11), and the other end of the first grounding metal post (13) is connected to the metal floor (31).

[0008] Further, the low-frequency antenna unit (2) includes: an S-shaped metal patch (21), a low-frequency coaxial feed structure (22), and a second grounding metal post (23); the S-shaped metal patch (21) is arranged parallel above the metal floor (31), the low-frequency coaxial feed structure (22) is arranged vertically on the metal floor (31), one end of the low-frequency coaxial feed structure (22) is connected to the S-shaped metal patch (21), and the other end of the low-frequency coaxial feed structure (22) passes through the metal floor (31); the second grounding metal post (23) is arranged vertically on the metal floor (31), one end of the second grounding metal post (23) is connected to the S-shaped metal patch (21), and the other end of the second grounding metal post (23) is connected to the metal floor (31).

[0009] Furthermore, the S-shaped metal patch (21) includes: a first bent metal arm (211) and a second bent metal arm (212); the first bent metal arm (211) and the second bent metal arm (212) are arranged in parallel above the metal floor (31), the first bent metal arm (211) and the second bent metal arm (212) are centrally symmetrical, and one end of the low-frequency coaxial power supply structure (22) is connected to the first bent metal arm (211); the second grounding metal post (23) is vertically arranged on the metal floor (31), and one end of the second grounding metal post (23) is connected to the second bent metal arm (212).

[0010] Furthermore, the high-frequency coaxial power supply structure (12) and the low-frequency coaxial power supply structure (22) use air as the medium.

[0011] Furthermore, the high-frequency coaxial feed structure (12) and the low-frequency coaxial feed structure (22) are made of solid dielectric.

[0012] An antenna array is provided, which employs multiple antenna subarrays. The antenna subarrays are arranged in a square array of two rows and two columns, consisting of a first antenna element, a second antenna element, a third antenna element, and a fourth antenna element. The first antenna element is a dual-frequency, dual-circularly polarized, common-aperture, high-gain back cavity antenna. The second antenna element, the third antenna element, and the fourth antenna element are obtained by rotating the first antenna element around its vertex by 90°, 180°, and 270° respectively.

[0013] Furthermore, the second antenna unit, the third antenna unit, and the fourth antenna unit are respectively obtained by translating the first antenna unit.

[0014] Furthermore, the antenna array is manufactured as a single unit.

[0015] The advantages of this invention are: The high-frequency and low-frequency antenna elements of this invention generate circularly polarized radiation with different rotation directions. The polarization of the high-frequency and low-frequency antenna elements is orthogonal, which helps to reduce mutual coupling and improve the overall performance of the common-aperture antenna. The metal ground plane and the metal frame form a closed rectangular metal cavity with an opening at the top. The rectangular metal back cavity structure can effectively improve the antenna gain and give the antenna a stable radiation pattern and a small back lobe radiation. The antenna of this invention has a simple structure, low profile, and wide bandwidth. The antenna is made of all-metal material and has the advantages of high radiation efficiency and large power capacity. The antenna has a flat structure, which is extremely convenient for array applications. The main structure of the antenna can be manufactured by milling, which is a mature manufacturing process with high reliability, wide application range, and low cost. The main body of the antenna array can be machined as a whole, instead of machining the elements separately and then splicing them together, which ensures the machining accuracy and reduces the machining cost. Attached Figure Description

[0016] Figure 1 This is a three-dimensional structural schematic diagram of the dual-frequency dual-circularly polarized common-aperture high-gain cavity antenna according to Embodiment 1 of the present invention. Figure 2 This is a top view of the dual-frequency dual-circularly polarized common-aperture high-gain cavity antenna according to Embodiment 1 of the present invention; Figure 3 This is a three-dimensional structural schematic diagram of the rectangular metal back cavity according to Embodiment 1 of the present invention; Figure 4 This is a three-dimensional structural schematic diagram of the high-frequency antenna unit according to Embodiment 1 of the present invention; Figure 5 This is a top view of the high-frequency antenna unit according to Embodiment 1 of the present invention; Figure 6 This is a three-dimensional structural schematic diagram of the low-frequency antenna unit according to Embodiment 1 of the present invention; Figure 7 This is a top view of the low-frequency antenna unit according to Embodiment 1 of the present invention; Figure 8 This is a schematic diagram of the antenna array configuration according to Embodiment 2 of the present invention. Detailed Implementation

[0017] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. 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 those skilled in the art without creative effort are within the scope of protection of the present invention.

[0018] The technical solution of the present invention will be further described below with reference to the accompanying drawings and specific embodiments: Example 1 like Figures 1 to 3 As shown, a dual-frequency dual-circular polarization common aperture high-gain cavity antenna according to an embodiment of the present invention includes: four high-frequency antenna elements (1), a low-frequency antenna element (2), and a rectangular metal cavity (3).

[0019] The rectangular metal back cavity (3) includes a metal ground plane (31) and a metal frame (32). The metal ground plane (31) and the metal frame (32) form a closed rectangular metal cavity with an opening at the top. The rectangular metal back cavity (3) structure can effectively improve the antenna gain and enable the antenna to have a stable radiation pattern and a small back lobe radiation.

[0020] Four high-frequency antenna units (1) form a square array in two rows and two columns and are set in a rectangular metal back cavity (3). The projection of the four high-frequency antenna units (1) in the square array in two rows and two columns on the metal floor (31) is centrally symmetrical about the center point of the metal floor (31). The low-frequency antenna unit (2) is set at the center of the rectangular metal back cavity (3). The low-frequency antenna unit (2) is embedded between the four high-frequency antenna units (1) in a nested common aperture manner. Both the high-frequency antenna unit (1) and the low-frequency antenna unit (2) are set on the metal floor (31) and share the metal floor (31).

[0021] The high-frequency antenna unit (1) and the low-frequency antenna unit (2) generate circularly polarized radiation with different rotation directions. The polarization of the high-frequency antenna unit (1) and the low-frequency antenna unit (2) is orthogonal, which helps to reduce mutual coupling and improve the overall performance of the common aperture antenna.

[0022] like Figure 4 and Figure 5 As shown, the high-frequency antenna unit (1) includes: a U-shaped metal patch (11), a high-frequency coaxial feed structure (12), and a first grounding metal post (13); the U-shaped metal patch (11) is arranged parallel above the metal floor (31), the high-frequency coaxial feed structure (12) is arranged vertically on the metal floor (31), one end of the high-frequency coaxial feed structure (12) is connected to the U-shaped metal patch (11), and the other end of the high-frequency coaxial feed structure (12) passes through the metal floor (31); the first grounding metal post (13) is arranged vertically on the metal floor (31), one end of the first grounding metal post (13) is connected to the U-shaped metal patch (11), and the other end of the first grounding metal post (13) is connected to the metal floor (31).

[0023] Figure 4 and Figure 5 The high-frequency antenna unit (1) shown operates in left-hand circular polarization mode. After swapping the positions of the high-frequency coaxial feed structure (12) and the first ground metal post (13), the high-frequency antenna unit (1) operates in right-hand circular polarization mode.

[0024] like Figure 6 and Figure 7As shown, the low-frequency antenna unit (2) includes: an S-shaped metal patch (21), a low-frequency coaxial feed structure (22), and a second grounding metal post (23). The S-shaped metal patch (21) includes: a first bent metal arm (211) and a second bent metal arm (212). The first bent metal arm (211) and the second bent metal arm (212) are arranged parallel above the metal floor (31), and the first bent metal arm (211) and the second bent metal arm (212) are centrally symmetrical. The low-frequency coaxial feed structure (22) is vertically mounted on the metal floor (31). One end of the low-frequency coaxial feed structure (22) is connected to the first bent metal arm (211), and the other end of the low-frequency coaxial feed structure (22) passes through the metal floor (31). The second grounding metal post (23) is vertically mounted on the metal floor (31). One end of the second grounding metal post (23) is connected to the second bent metal arm (212), and the other end of the second grounding metal post (23) is connected to the metal floor (31).

[0025] Figure 6 and Figure 7 The low-frequency antenna unit (2) shown operates in right-hand circular polarization mode. After swapping the positions of the low-frequency coaxial feed structure (22) and the second ground metal post (23), the low-frequency antenna unit (2) operates in left-hand circular polarization mode.

[0026] The high-frequency coaxial feed structure (12) and the low-frequency coaxial feed structure (22) can be made of air or solid medium.

[0027] The working principle of the antenna is as follows: When the antenna is working, the high-frequency electromagnetic signal is fed into the four high-frequency antenna elements (1) by the high-frequency coaxial feeding structure (12), and the low-frequency electromagnetic signal is fed into the low-frequency antenna element (2) by the low-frequency coaxial feeding structure (22). The high-frequency antenna element (1) and the low-frequency antenna element (2) generate circular polarization radiation with different rotation directions. The polarization of the high-frequency antenna element (1) and the low-frequency antenna element (2) is orthogonal, which helps to reduce mutual coupling and improve the overall performance of the common aperture antenna. The metal ground plane (31) and the metal frame (32) form a closed rectangular metal cavity with an opening at the top. The rectangular metal back cavity (3) structure can effectively improve the antenna gain and make the antenna have a stable radiation pattern and a small back lobe radiation.

[0028] Example 2 like Figure 8As shown, a 4×4 antenna array is constructed using the dual-frequency, dual-circularly polarized, common-aperture, high-gain cavity antenna from Embodiment 1. Antenna elements B, C, and D are obtained by rotating antenna element A sequentially by 90°, 180°, and 270° around its vertex, respectively, or by translating antenna element A. In both the antenna elements and the antenna array, the high-frequency antenna element (1) and the low-frequency antenna element (2) are arranged in a rotating configuration to improve the circular polarization performance of the common-aperture antenna and its array. The antenna array is manufactured as a single unit, rather than by independently manufacturing and then assembling the elements. This method ensures manufacturing accuracy and reduces manufacturing costs.

[0029] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A dual-frequency, dual-circularly polarized, common-aperture, high-gain cavity back-end antenna, characterized in that, include: The high-frequency antenna unit array, the low-frequency antenna unit (2), and the rectangular metal back cavity (3) are provided. The rectangular metal back cavity (3) includes a metal floor (31) and a metal frame (32). The metal floor (31) and the metal frame (32) form a closed rectangular metal cavity with an opening at the top. The high-frequency antenna unit array is set inside the rectangular metal back cavity (3). The low-frequency antenna unit (2) is set at the center position inside the rectangular metal back cavity (3). The low-frequency antenna unit (2) is embedded between the high-frequency antenna unit array in a nested common aperture manner. The high-frequency antenna unit array and the low-frequency antenna unit (2) share the metal floor (31). The high-frequency antenna unit array and the low-frequency antenna unit (2) generate circularly polarized radiation with different rotation directions. The polarization of the high-frequency antenna unit array and the low-frequency antenna unit (2) is orthogonal. The high-frequency antenna unit array is composed of 4 high-frequency antenna units (1). The projection of the 4 high-frequency antenna units (1) forming a square array in two rows and two columns on the metal floor (31) is centrally symmetrical about the center point of the metal floor (31). The high-frequency antenna unit (1) includes: a U-shaped metal patch (11), a high-frequency coaxial feed structure (12), and a first grounding metal post (13); the U-shaped metal patch (11) is arranged parallel above the metal floor (31), the high-frequency coaxial feed structure (12) is arranged vertically on the metal floor (31), one end of the high-frequency coaxial feed structure (12) is connected to the U-shaped metal patch (11), and the other end of the high-frequency coaxial feed structure (12) passes through the metal floor (31); the first grounding metal post (13) is arranged vertically on the metal floor (31), one end of the first grounding metal post (13) is connected to the U-shaped metal patch (11), and the other end of the first grounding metal post (13) is connected to the metal floor (31); The low-frequency antenna unit (2) includes: an S-shaped metal patch (21), a low-frequency coaxial feed structure (22), and a second grounding metal post (23); the S-shaped metal patch (21) is arranged parallel above the metal floor (31), the low-frequency coaxial feed structure (22) is arranged vertically on the metal floor (31), one end of the low-frequency coaxial feed structure (22) is connected to the S-shaped metal patch (21), and the other end of the low-frequency coaxial feed structure (22) passes through the metal floor (31); the second grounding metal post (23) is arranged vertically on the metal floor (31), one end of the second grounding metal post (23) is connected to the S-shaped metal patch (21), and the other end of the second grounding metal post (23) is connected to the metal floor (31); The positions of the high-frequency coaxial feed structure (12) and the first grounding metal post (13) can be interchanged, and the positions of the low-frequency coaxial feed structure (22) and the second grounding metal post (23) can be interchanged.

2. The dual-frequency, dual-circularly polarized, common-aperture high-gain cavity antenna according to claim 1, characterized in that, The S-shaped metal patch (21) includes: a first bent metal arm (211) and a second bent metal arm (212); the first bent metal arm (211) and the second bent metal arm (212) are arranged in parallel above the metal floor (31), the first bent metal arm (211) and the second bent metal arm (212) are centrally symmetrical, and one end of the low-frequency coaxial power supply structure (22) is connected to the first bent metal arm (211); the second grounding metal post (23) is vertically arranged on the metal floor (31), and one end of the second grounding metal post (23) is connected to the second bent metal arm (212).

3. The dual-frequency, dual-circularly polarized, common-aperture high-gain cavity antenna according to claim 1, characterized in that, The high-frequency coaxial power supply structure (12) and the low-frequency coaxial power supply structure (22) use air as the medium.

4. The dual-frequency, dual-circularly polarized, common-aperture high-gain cavity antenna according to claim 1, characterized in that, The high-frequency coaxial power supply structure (12) and the low-frequency coaxial power supply structure (22) are made of solid dielectric.

5. An antenna array, characterized in that, Multiple antenna subarrays are used in an array. The antenna subarrays are arranged in a square array of two rows and two columns, consisting of a first antenna element, a second antenna element, a third antenna element, and a fourth antenna element. The first antenna element is a dual-frequency dual-circularly polarized common-aperture high-gain cavity antenna as described in any one of claims 1 to 4. The second antenna element, the third antenna element, and the fourth antenna element are obtained by rotating the first antenna element around its vertex by 90°, 180°, and 270° respectively, or the second antenna element, the third antenna element, and the fourth antenna element are obtained by translating the first antenna element.

6. The antenna array according to claim 5, characterized in that, The antenna array is manufactured as a single unit.

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