Ka low-profile circularly polarized array antenna

Abstract

The invention discloses a Ka low-profile circularly polarized array antenna which can work in a ka frequency band and comprises a transmitting antenna and a receiving antenna, the transmitting antenna comprises 192 radiation array elements, the receiving antenna comprises 288 radiation array elements, and the whole array is composed of a low-profile radiation array, a feed network and a polarization layer. The low-profile radiation array and the feed network can realize signal radiation and reception of a horizontal component and a vertical component, and the polarization layer can realize synthesis of left-handed and right-handed circular polarization array elements. The overall height of the antenna is reduced; and the lightweight requirement of the antenna is realized. According to the invention, the ET flat waveguide is adopted to realize horizontal polarization and vertical polarization feed network arrangement of transmitting and receiving frequency bands, and the height of the feed network is reduced. The transmitting circular polarizer and the receiving circular polarizer of the polarization layer adopt a 3dB bridge form, and the rear end is connected with the polarization switch, so that the whole network is simple and easy to process, and the processing cost is reduced.

Description

Technical Field

[0001] The present invention relates to the field of communication technologies, and particularly to a Ka low-profile circularly polarized array antenna. Background Art

[0002] Planar array antennas are an essential part of satellite communication systems, and their electrical performance directly affects the quality of satellite communication. Due to the advantages of high gain, light weight, and low profile, planar array antennas have various implementation forms. Currently, the main forms of planar array antennas are microstrip array antennas, slot array antennas, and traditional horn array antennas.

[0003] The main radiation element of a microstrip array antenna is a patch antenna, which is generally implemented by a single-layer or multi-layer PCB structure. It has the characteristics of simple design, light weight, low profile, and easy integration. However, due to the large transmission line loss of the microstrip array antenna in the Ka band and the mutual coupling between array elements, the aperture efficiency of the microstrip array antenna is relatively low.

[0004] Waveguide slot array antennas are formed by opening slots on a conductor surface. They are characterized by low profile, integratability, and easy array formation. However, due to their large losses, the feeding efficiency is reduced, and the fact that it is not easy to form circular polarization is also a disadvantage of waveguide slot array antennas.

[0005] Traditional horn array antennas have the advantages of wide bandwidth, low loss in the feeding network, and high radiation efficiency. Therefore, horn array antennas have great application prospects in engineering practice. However, they also have their disadvantages. Since the height of the radiation cavity of traditional horn array antennas is relatively large, the overall longitudinal size of the antenna becomes larger, thus increasing the weight of the entire antenna.

[0006] The present invention proposes a form of Ka low-profile circularly polarized array antenna. Compared with traditional horn arrays, it reduces the height of the antenna radiation cavity, realizes a lower-profile planar antenna size, thereby reducing the overall longitudinal size of the antenna and reducing the weight of the antenna to meet the lightweight requirement.

[0007] Chinese Patent CN11781694A discloses a dual-frequency broadband co-polarized common-aperture low-profile antenna, which realizes the low profile of the antenna by etching radiation slots on a hot-pressed dielectric substrate. However, this solution introduces three layers of dielectric substrates, resulting in relatively large losses of the antenna and making it difficult to achieve high gain. Patent CN 117878623A discloses a low sidelobe low-profile high-gain planar array antenna. This solution uses a bowtie slot-loaded rectangular cavity to achieve high gain of the antenna. However, the waveguide slot antenna form is linearly polarized and it is difficult to meet the circular polarization requirement of the antenna. Summary of the Invention

[0008] The object of the present invention is to provide a Ka low-profile circularly polarized array antenna to solve the existing technical problems. It operates in the Ka band, and realizes the high-gain and low-sidelobe characteristics of the Ka antenna through a low-profile radiation array, a transceiver feeding network, and a polarization layer. The low profile of the antenna is achieved by reducing the height of the radiation cavity. The low-profile radiation array and the feeding network can realize the radiation and reception of signals in two horizontal and vertical components, and the polarization layer can realize the synthesis of left- and right-handed circularly polarized array elements.

[0009] To achieve the above object, the present invention adopts the following technical solutions: A Ka low-profile circularly polarized array antenna capable of operating in the ka band, including a transmitting antenna and a receiving antenna. The transmitting antenna includes 192 radiation elements, and the receiving antenna includes 288 radiation elements. The entire array is composed of a low-profile radiation array, a feeding network, and a polarization layer. The low-profile radiation array and the feeding network can realize the radiation and reception of signals in two horizontal and vertical components, and the polarization layer can realize the synthesis of left- and right-handed circularly polarized array elements.

[0010] Preferably: The low-profile radiation array is composed of a low-profile radiation layer of the transmitting antenna and a low-profile radiation layer of the receiving antenna. The feeding network is composed of a horizontal polarization feeding network layer of the transmitting antenna, a vertical polarization feeding network layer of the transmitting antenna, a horizontal polarization feeding network layer of the receiving antenna, and a vertical polarization feeding network layer of the receiving antenna.

[0011] Preferably: The height of the transmitting antenna array surface is 25 mm, the height of the receiving antenna array surface is 35 mm, and the insertion loss of the array surface is less than 0.4 dB.

[0012] Preferably: The feeding network is composed of a horizontal polarization feeding network layer of the transmitting antenna, a vertical polarization feeding network layer of the transmitting antenna, a horizontal polarization feeding network layer of the receiving antenna, and a vertical polarization feeding network layer of the receiving antenna. The horizontal polarization feeding layer of the transmitting antenna, the vertical polarization feeding layer of the transmitting antenna, the horizontal polarization feeding network layer of the receiving antenna, and the vertical polarization feeding network layer of the receiving antenna respectively adopt the flat antenna shaping technology to make the radiation signal satisfy the medium-high side-low distribution, greatly reducing the antenna sidelobe, and the first sidelobe is less than -15 dB.

[0013] Preferably: The polarization layer includes waveguide 1, waveguide 2, a transmitting circular polarizer, waveguide 3, waveguide 4, and a receiving circular polarizer. Waveguide 1, waveguide 2, waveguide 3, and waveguide 4 adjust the length to match the phases of the horizontal polarization feeding layer and the vertical polarization feeding layer of the antenna. The transmitting circular polarizer and the receiving circular polarizer respectively realize the synthesis of circularly polarized signals of the transmitting antenna and the receiving antenna. The insertion loss of the entire polarization layer is less than 0.5 dB, and the axial ratio is less than 1.5 dB.

[0014] The low-profile radiation array transitions from a circular waveguide to a rectangular waveguide. The rectangular waveguide undergoes a stepped transformation for radiation matching, and then radiation interference is achieved through a 2×2 circular convex to reach the optimal radiation. The spacing between the low-profile radiation elements is 0.8λ, where λ is the operating wavelength of the antenna. This can suppress the appearance of antenna grating lobes.

[0015] The feeding network of the array antenna adopts a waveguide feeding form. In the radiation elements, horizontal polarization and vertical polarization are separated through rectangular aperture coupling. Among them, the horizontal polarization and vertical polarization are respectively shaped using a modified Taylor distribution to make the radiation signal satisfy the middle-high side-low distribution, significantly reducing the antenna side lobes. The first side lobe is less than -15 dB.

[0016] The transmitting circular polarizer and the receiving circular polarizer can realize the electromagnetic vector synthesis of the horizontal polarization and vertical polarization of the antenna, forming left-handed and right-handed dual polarizations.

[0017] Compared with the prior art, the present invention has the following advantages: The Ka low-profile circularly polarized array antenna of the present invention adopts low-profile radiation elements. The height of the transmitting antenna array surface is 25 mm, and the height of the receiving antenna array surface is 35 mm, reducing the overall height of the antenna; the lightweight requirement of the antenna is achieved.

[0018] The Ka low-profile circularly polarized array antenna of the present invention is shaped using a modified Taylor distribution to make the radiation signal satisfy the middle-high side-low field distribution and reduce the antenna side lobes. The ET flat waveguide is used to arrange the feeding network for horizontal polarization and vertical polarization in the transmitting and receiving frequency bands, reducing the height of the feeding network.

[0019] The Ka low-profile circularly polarized array antenna of the present invention adopts a 3dB bridge form for the polarization layer transmitting circular polarizer and receiving circular polarizer, which is realized by connecting a polarization switch at the back end. The entire network is simple and easy to process, reducing the processing cost. Description of the Drawings

[0020] Figure 1 It is a schematic diagram of the overall structure of the present invention.

[0021] Figure 2 It is the antenna radiation element of the present invention.

[0022] Figure 3 It is the one-to-four power divider of the antenna feeding network layer of the present invention.

[0023] Figure 4 It is the front view of the antenna array of the present invention.

[0024] Figure 5 It is the back view of the antenna array of the present invention.

[0025] Figure 6 It is the antenna gain pattern of the present invention.

[0026] In the figure: the low-profile radiation layer 1 of the transmitting antenna, the horizontal polarization feeding network layer 2 of the transmitting antenna, the vertical polarization feeding network layer 3 of the transmitting antenna, waveguide 1 4, waveguide 2 5, transmitting circular polarizer 6, the low-profile radiation layer 7 of the receiving antenna, the horizontal polarization feeding network layer 8 of the receiving antenna, the vertical polarization feeding network layer 9 of the receiving antenna, waveguide 3 10, waveguide 4 11, receiving circular polarizer 12. Specific implementation mode

[0027] The present invention will be further elaborated in detail below in conjunction with the accompanying drawings and specific embodiments.

[0028] As Figure 1 shown, a Ka low-profile circular polarization array antenna capable of operating in the ka frequency band, including a transmitting antenna and a receiving antenna. The transmitting antenna includes 192 radiation elements, and the receiving antenna includes 288 radiation elements. The entire array is respectively composed of a low-profile radiation array, a feeding network, and a polarization layer. The low-profile radiation array and the feeding network can realize the signal radiation and reception of two components, horizontal and vertical, and the polarization layer can realize the synthesis of left- and right-handed circular polarization elements.

[0029] The low-profile radiation array is composed of the low-profile radiation layer 1 of the transmitting antenna and the low-profile radiation layer 7 of the receiving antenna. The feeding network is composed of the horizontal polarization feeding network layer 2 of the transmitting antenna, the vertical polarization feeding network layer 3 of the transmitting antenna, the horizontal polarization feeding network layer 8 of the receiving antenna, and the vertical polarization feeding network layer 9 of the receiving antenna. The height of the transmitting antenna array surface is 25 mm, the height of the receiving antenna array surface is 35 mm, and the insertion loss of the array surface is less than 0.4 dB.

[0030] The feeding network is composed of the horizontal polarization feeding network layer 2 of the transmitting antenna, the vertical polarization feeding network layer 3 of the transmitting antenna, the horizontal polarization feeding network layer 8 of the receiving antenna, and the vertical polarization feeding network layer 9 of the receiving antenna. The horizontal polarization feeding layer 2 of the transmitting antenna, the vertical polarization feeding layer 3 of the transmitting antenna, the horizontal polarization feeding network layer 8 of the receiving antenna, and the vertical polarization feeding network layer 9 of the receiving antenna respectively adopt the flat antenna shaping technology to make the radiation signal satisfy the medium-high side-low distribution, greatly reducing the antenna side lobe, and the first side lobe is less than -15 dB.

[0031] The polarization layer includes waveguide 1 4, waveguide 2 5, transmitting circular polarizer 6, waveguide 3 10, waveguide 4 11, and receiving circular polarizer 12. Waveguide 1 4, waveguide 2 5, waveguide 3 10, and waveguide 4 11 adjust the length to match the phases of the horizontal polarization feeding layer and the vertical polarization feeding layer of the antenna. The transmitting circular polarizer 6 and the receiving circular polarizer 12 respectively realize the synthesis of the circular polarization signals of the transmitting antenna and the receiving antenna. The insertion loss of the entire polarization layer is less than 0.5 dB, and the axial ratio is less than 1.5 dB.

[0032] The low-profile radiation array transitions from a circular waveguide to a rectangular waveguide. The rectangular waveguide undergoes a step transformation for radiation matching, and then radiation interference is achieved through a 2×2 circular convex to achieve optimal radiation. The spacing between the low-profile radiation units is 0.8λ, where λ is the operating wavelength of the antenna. This can suppress the appearance of antenna grating lobes.

[0033] The feed network of the array antenna adopts a waveguide feed form. In the radiation unit, horizontal polarization and vertical polarization are separated through rectangular port coupling. Among them, the horizontal polarization and vertical polarization are respectively shaped using a modified Taylor distribution to make the radiation signal satisfy the middle-high side-low distribution, significantly reducing the antenna side lobes, and the first side lobe is less than -15 dB.

[0034] The transmitting circular polarizer 6 and the receiving circular polarizer 12 can realize the electromagnetic vector synthesis of the horizontal polarization and vertical polarization of the antenna, forming left-handed and right-handed dual polarizations.

[0035] As Figure 2 shown in the antenna radiation unit, the low-profile radiation unit transitions from a circular waveguide to a rectangular waveguide. The rectangular waveguide undergoes a step transformation for radiation matching, and then radiation interference is achieved through a 2×2 circular convex to achieve optimal radiation. The radiation is arranged at a spacing of 0.8λ to suppress antenna grating lobes.

[0036] As Figure 3 shown, the antenna feed network adopts a waveguide feed form. In the radiation unit, horizontal polarization and vertical polarization are separated through rectangular port coupling. Among them, the horizontal polarization and vertical polarization are respectively shaped using a modified Taylor distribution to make the radiation signal satisfy the middle-high side-low distribution.

[0037] ; .

[0038] As Figure 4 shown in the front view of the array antenna, it mainly consists of two parts: a transmitting antenna and a receiving antenna. The transmitting part contains 192 radiation array elements, and the receiving antenna contains 288 radiation array elements. Each radiation unit transitions to the radiation layer through a step transformation. Orthogonal feed polarizations are respectively coupled out at the circular waveguide, corresponding to two different feed networks, forming the signal radiation and reception of the horizontal and vertical components of the transmitting antenna and the receiving antenna.

[0039] As Figure 5 shown in the rear view of the antenna array, the polarization layer realizes the arrangement of the feed networks for horizontal polarization and vertical polarization in the transmitting and receiving frequency bands by using an HT flat waveguide, reducing the height of the feed network. The backplane has a total horizontal polarization port and a total vertical polarization port, providing an interface for the switching of the dual-polarization signal direction. The transmitting circular polarizer and the receiving circular polarizer of the polarization layer adopt a 3 dB bridge form to realize the left-handed and right-handed circular polarizations of the antenna.

[0040] 。

[0041] The above is a preferred embodiment of the present invention. For those of ordinary skill in the art, according to the teachings of the present invention, without departing from the principles and spirit of the present invention, the changes, modifications, substitutions, and variations made to the embodiments still fall within the protection scope of the present invention.

Claims

1. A Ka low profile circularly polarized array antenna, characterized in that: It can work in the Ka-band, including a transmitting antenna and a receiving antenna. The transmitting antenna contains 192 radiating elements and the receiving antenna contains 288 radiating elements. The entire array is composed of a low-profile radiating array, a feeding network and a polarization layer. The low-profile radiating array and the feeding network can realize the signal radiation and reception of both horizontal and vertical components. The polarization layer can realize the synthesis of left-handed and right-handed circularly polarized array elements.

2. A Ka low profile circularly polarized array antenna as claimed in claim 1, characterized in that: The low-profile radiation array is composed of a transmitting antenna low-profile radiation layer (1) and a receiving antenna low-profile radiation layer (7), and the feeding network is composed of a transmitting antenna horizontal polarization feeding network layer (2), a transmitting antenna vertical polarization feeding network layer (3), a receiving antenna horizontal polarization feeding network layer (8) and a receiving antenna vertical polarization feeding network layer (9).

3. A Ka low profile circularly polarized array antenna according to claim 1, characterized in that: The transmitting antenna array height is 25mm, the receiving antenna array height is 35mm, and the array insertion loss is less than 0.4dB.

4. A Ka low profile circularly polarized array antenna as claimed in claim 1, characterized in that: The feeding network is composed of a transmitting antenna horizontal polarization feeding network layer (2), a transmitting antenna vertical polarization feeding network layer (3), a receiving antenna horizontal polarization feeding network layer (8) and a receiving antenna vertical polarization feeding network layer (9). The transmitting antenna horizontal polarization feeding layer (2), the transmitting antenna vertical polarization feeding layer (3), the receiving horizontal polarization feeding network layer (8) and the receiving vertical polarization feeding network layer (9) respectively adopt flat-panel antenna shaping technology, so that the radiated signal meets the high-mid-side low distribution, greatly reduces the antenna side lobe, and the first side lobe is less than -15dB.

5. A Ka low profile circularly polarized array antenna as claimed in claim 1, characterized in that: The polarization layer comprises waveguide 1 (4), waveguide 2 (5), a transmitting circular polarizer (6), waveguide 3 (10), waveguide 4 (11) and a receiving circular polarizer (12). The waveguide 1 (4), waveguide 2 (5), waveguide 3 (10) and waveguide 4 (11) are length-adjusted to match the phases of the horizontal polarization feeding layer and the vertical polarization feeding layer of the antenna. The transmitting circular polarizer (6) and the receiving circular polarizer (12) respectively realize the synthesis of circular polarization signals of the transmitting antenna and the receiving antenna. The insertion loss of the entire polarization layer is less than 0.5 dB, and the axial ratio is less than 1.5 dB.

6. A Ka low profile circularly polarized array antenna as claimed in claim 1, characterized in that: The low-profile radiation array is a transition from a circular waveguide to a square waveguide. The square waveguide is transformed into a step to perform radiation matching, and then the radiation interference is performed through a 2×2 circular convex to achieve optimal radiation. The spacing between the low-profile radiation units is 0.8λ, where λ is the working wavelength of the antenna. This can suppress the appearance of antenna grating lobes.

7. A Ka low profile circularly polarized array antenna as claimed in claim 1, characterized in that: The array antenna feeding network adopts a waveguide feeding form, and the horizontal polarization and the vertical polarization are separated in the radiating unit by a rectangular mouth coupling method, wherein the horizontal polarization and the vertical polarization are respectively shaped by a modified Taylor distribution, so that the radiation signal satisfies the middle-high-side-low distribution, greatly reducing the antenna side lobe, and the first side lobe is less than -15dB.

8. A Ka low profile circularly polarized array antenna as claimed in claim 5, characterized in that: The transmitting circular polarizer (6) and the receiving circular polarizer (12) realize electromagnetic vector synthesis of horizontal polarization and vertical polarization of the antenna, forming left-handed and right-handed dual polarization.

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