Low-profile broadband transmission array antenna based on multi-resonant structure

Abstract

The invention belongs to the technical field of wireless communication, and particularly relates to a low-profile broadband transmission array antenna based on a multi-resonant structure. The antenna comprises a multi-resonant-structure transmission array surface and a polarization torsion reflection surface. The multi-resonant structure transmission array surface is arranged above the polarization torsion reflection surface through a support frame; the multi-resonant structure transmission array surface comprises a plurality of multi-resonant structure antenna units which are periodically arranged; the multi-resonant-structure antenna unit is of a multi-layer stacked structure, sequentially comprises an upper-layer metasurface layer, an upper-layer dielectric substrate, a middle metal ground layer, a bonding layer, a lower-layer dielectric substrate, a lower-layer metasurface layer and a coaxial structure from top to bottom, and is used for conducting electromagnetic energy; a circular through hole is etched in the center of the middle metal ground layer; the polarization torsion reflection surface comprises a plurality of polarization torsion reflection surface units which are arranged periodically, and the middle of the polarization torsion reflection surface is hollowed out and used for placing a feed source horn.

Description

Technical Field

[0001] The present invention belongs to the technical field of wireless communication, and particularly relates to a low-profile broadband transmissive array antenna based on a multi-resonant structure. Background Art

[0002] In the field of modern wireless communication, as a key component, the performance of an antenna directly affects the quality of a communication system. With the rapid development of technology, circular polarization, antenna miniaturization, and multi-resonant structures, as key elements driving the progress of communication technology, are profoundly changing the pattern of wireless communication.

[0003] The advantages of circular polarization in communication are becoming increasingly prominent. In a complex electromagnetic environment, the stable transmission of signals is crucial. Compared with the traditional linear polarization method, circular polarization has unique characteristics when facing multipath interference and polarization mismatch problems, and can effectively overcome these problems. On the one hand, circular polarization antennas do not require strict polarization matching during the reception and transmission processes, greatly improving the flexibility of communication. On the other hand, circular polarization antennas have excellent anti-multipath reflection capabilities. During signal propagation, when encountering obstacles, the interference of reflected waves is effectively suppressed, ensuring the stable transmission of signals. At the same time, the design of antenna miniaturization is also one of the key research hotspots in the field of modern communication. Currently, common design methods include planar folding, three-dimensional folding, folding based on fractal theory, and dynamic folding using reconfigurable materials, etc. However, due to the existence of polarization gratings, most folding antennas can only generate linear polarization, and it is still a huge challenge to realize a circularly polarized folded reflective array antenna. Traditional reflective arrays and transmissive array antennas have attracted much attention due to their advantages such as high gain, low cost, planarization, and easy processing. However, the distance between their feed sources and phase compensation arrays is relatively large, resulting in a large overall volume. Although some studies have achieved a certain degree of size reduction by changing the patch shape, such as designing it into a bent shape, circular shape, etc., the antenna performance, such as radiation efficiency, bandwidth, etc., is often affected to varying degrees, and the existence of the feed source still makes the total height of the antenna system relatively high.

[0004] In addition, traditional rectangular patch antennas are widely used in wireless communication devices due to their simple structure and ease of manufacturing. However, their large size makes it difficult to meet the requirements of miniaturization and integration in modern electronic devices. As an innovative solution to improve antenna performance, multi-resonant structures have received extensive attention in recent years. A multi-resonant structure enables an antenna to resonate at multiple different frequencies, greatly expanding the operating bandwidth of the antenna. By carefully designing the size, shape, and coupling method between resonant elements, not only can broadband characteristics be achieved, but also the radiation efficiency of the antenna can be enhanced. Traditional single-resonant antennas often have limitations in bandwidth and radiation characteristics and are difficult to meet the requirements of multi-band and high-speed communication in modern communication. The introduction of multi-resonant structures provides a new way to solve these problems. In practical applications, combining circular polarization, antenna miniaturization, and multi-resonant structures can bring more powerful performance to wireless communication systems. In satellite communication, using a miniaturized circularly polarized antenna based on a metasurface can improve the signal reception quality, enhance the anti-interference ability, and at the same time reduce the payload weight of the satellite; in 5G and even future 6G communication, the integration of these technologies helps to achieve miniaturization and high performance of base station antennas and meet the requirements of high-speed and large-capacity communication. Summary of the Invention

[0005] Aiming at the above deficiencies in the prior art, the present invention proposes a low-profile broadband transmissive array antenna based on a multi-resonant structure, which can achieve a relatively wide bandwidth at a relatively low profile.

[0006] To achieve the above invention objectives, the present invention adopts the following technical solutions: A low-profile broadband transmissive array antenna based on a multi-resonant structure, comprising a multi-resonant structure transmissive array surface and a polarization-rotation reflection surface; the multi-resonant structure transmissive array surface is arranged above the polarization-rotation reflection surface through a support frame; the multi-resonant structure transmissive array surface includes a plurality of multi-resonant structure antenna elements arranged periodically; the multi-resonant structure antenna element is a multi-layer stacked structure, which sequentially includes an upper metasurface layer, an upper dielectric substrate, a middle metal ground layer, an adhesive layer, a lower dielectric substrate, a lower metasurface layer, and a coaxial structure for conducting electromagnetic energy; a circular through-hole is etched in the center of the middle metal ground layer; the polarization-rotation reflection surface includes a plurality of polarization-rotation reflection surface elements arranged periodically, and the middle of the polarization-rotation reflection surface is hollowed out for placing a feed horn.

[0007] Further, as a preferred technical solution of the present invention, the coaxial structure is located at the geometric center of the multi-resonant structure antenna element and is cylindrical in shape.

[0008] Further, as a preferred technical solution of the present invention, the upper metasurface layer is etched with a C-shaped slot, and the lower metasurface layer is a stepped rectangular metal patch.

[0009] Further, as a preferred technical solution of the present invention, both the upper metasurface layer and the lower metasurface layer include an upper polarization conversion patch and a lower polarization selection patch.

[0010] Further, as a preferred technical solution of the present invention, the upper dielectric substrate and the lower dielectric substrate have the same thickness.

[0011] Further, as a preferred technical solution of the present invention, the lower metasurface layer is a multi-resonant structure formed by splicing three rectangular metal patches; the width of the middle rectangular metal patch is three times the width of the small rectangular metal patch, and the sum of the width of the middle rectangular metal patch and the width of the small rectangular metal patch is not greater than the width of the large rectangular metal patch.

[0012] For the low-profile broadband transmissive array antenna based on a multi-resonant structure of the present invention, compared with the prior art by adopting the above technical solutions, it has the following technical effects:

[0013] (1) The low-profile broadband transmissive array antenna unit based on a multi-resonant structure proposed by the present invention has the characteristic of reflecting the energy in the X polarization direction and transmitting the energy in the Y polarization direction, has good polarization selection characteristics, can be applied to a folded transmission array, and reduces the overall profile of the array.

[0014] (2) The low-profile broadband transmissive array antenna unit based on a multi-resonant structure proposed by the present invention has a relatively wide -10dB transmission bandwidth.

[0015] (3) The low-profile broadband transmissive array antenna unit based on a multi-resonant structure proposed by the present invention realizes phase adjustment of more than 360 degrees by using the rotation of the upper metasurface, and can achieve linear phase within a relatively wide frequency band.

[0016] (4) Due to its polarization selection characteristics, the low-profile broadband transmissive array antenna based on a multi-resonant structure proposed by the present invention can reduce the profile to one-third by introducing a polarization-twisting reflection surface according to the ray tracing principle.

[0017] (5) The low-profile broadband transmissive array antenna based on a multi-resonant structure proposed by the present invention adopts a double-sided microwave dielectric board, has a simple structure, is easy to process, and has relatively small cost and weight, so it can be mass-produced. Description of the Drawings

[0018] Figure 1 It is a three-dimensional schematic diagram of the antenna in the embodiment of the present invention;

[0019] Figure 2 It is a cross-sectional schematic diagram of the antenna in the embodiment of the present invention;

[0020] Figure 3 It is a top view of the polarization converter;

[0021] Figure 4 It is a top view of the polarization-twisting reflection surface;

[0022] Figure 5 It is a schematic structural diagram of the antenna unit of the present invention;

[0023] Figure 6 It is Figure 5 a top view of the upper-middle metal patch layer;

[0024] Figure 7 It is Figure 5 a top view of the lower-middle metal patch layer;

[0025] Figure 8 It is a schematic diagram of the reflection and transmission characteristics of the polarization selector unit of the present invention;

[0026] Figure 9 It is the S-parameter curve graph of the present invention;

[0027] Figure 10 It is the curve of the gain of the present invention varying with frequency;

[0028] Figure 11 It is the curve of the axial ratio of the present invention varying with frequency;

[0029] Figure 12 It is the radiation pattern of the main polarization and cross polarization of the E-plane and H-plane of the present invention at 25 GHz;

[0030] In the drawings, 1 - multi-resonant structure antenna unit; 2 - polarization-twisting reflection surface unit; 3 - upper metasurface layer; 4 - upper dielectric substrate; 5 - intermediate metal ground layer; 6 - adhesive layer; 7 - lower dielectric substrate; 8 - lower metasurface layer; 9 - coaxial structure. Specific embodiments

[0031] The following further explains the present invention in detail with reference to the drawings, so that those skilled in the art can understand the present invention more deeply and be able to implement it. However, the following is only used to explain the present invention by reference to examples and does not limit the present invention.

[0032] As Figures 1-5 shown, a low-profile broadband transmissive array antenna based on a multi-resonant structure includes a multi-resonant structure transmissive array surface and a polarization-twisting reflection surface. The multi-resonant structure transmissive array surface is arranged above the polarization-twisting reflection surface through a support frame. The polarization-twisting reflection surface is composed of a plurality of polarization-twisting reflection surface units 2 arranged periodically. The middle of the polarization-twisting reflection surface is hollowed out for placing a feed horn.

[0033] The multi-resonant structure transmission array surface is composed of several multi-resonant structure antenna elements 1 arranged periodically. The multi-resonant structure antenna element 1 is a multi-layer stacked structure, which successively includes an upper metasurface layer 3, an upper dielectric substrate 4, an intermediate metal ground layer 5, an adhesive layer 6, a lower dielectric substrate 7, a lower metasurface layer 8 and a coaxial structure 9 from top to bottom, and is used to conduct electromagnetic energy. A circular through-hole is etched in the center of the intermediate metal ground layer 5.

[0034] The metal patch layer includes a polarization selection patch, a polarization conversion patch and a polarization rotation patch. In this embodiment, the shape of the polarization rotation patch is a triangular chamfered metal patch. In this embodiment, the polarization selection patch is a stepped rectangular metal patch. In this embodiment, the polarization conversion patch is a rectangular chamfered metal patch, and a C-shaped slot is etched in the middle of the patch. In this embodiment, a rectangular chamfered metal patch is used, and two corners of the rectangle diagonal are cut off.

[0035] The feed horn is directly connected to the standard waveguide WG260 of the signal source through a flange for feeding.

[0036] The feed horn outputs energy in the X polarization direction and is incident on the lower surface of the transmission array surface. Due to the polarization selection characteristic of the lower surface of the transmission array surface, the energy in the X polarization direction cannot pass through the structure, but is reflected to the polarization rotation reflection surface. The polarization rotation reflection surface polarizes the electric field in the X polarization direction by 90° into the electric field in the Y polarization direction and then is incident on the lower surface of the transmission array surface. At this time, several antenna elements on the transmission array surface receive the energy in the Y polarization direction through the lower metasurface layer, and are transmitted to the upper metasurface layer of the antenna element through the intermediate coaxial cylinder, and then the corresponding phase compensation is realized by rotating the upper metasurface layer. The upper metasurface layer radiates the energy in the Y polarization direction as an LCP wave into free space, so as to realize a transmission array antenna with broadband, high gain and low profile characteristics.

[0037] As Figures 6-7 shown, the dimensions of each part of the antenna element in this embodiment are as follows:

[0038] The dielectric constant ε r of the dielectric substrate involved in this embodiment is [3.1, 3.8], and the thickness is [0.05λ, 0.1λ], where λ is the free space wavelength.

[0039] The transmitting array multi-resonant structure antenna element has a square structure, and its side length p is in the range of [0.5λ, λ]. Among them, the length a of the upper metasurface patch is in the range of [0.25λ, 0.3λ], the parameter d of the C-shaped slot in the upper metasurface layer is in the range of [0.08λ, 0.14λ], the diameter d1 of the coaxial cylinder is in the range of [0.05λ, 0.06λ]. By changing d1, the input impedance of the antenna can be adjusted. The chamfer length t of the rectangular metal patch on the upper metasurface is in the range of [0.05λ, 0.07λ], and its position and size respectively control the polarization conversion patch to convert the Y-polarized wave into the LCP wave or the RCP wave. The total width width of the lower multi-resonant structure metasurface patch is width = k 12 +k 22 +k 32 is in the range of [0.2λ g , 0.25λ g , where λ g is the dielectric wavelength. By adjusting k 12 , k 22 , k 32 , the operating frequency of the antenna, the number and position of the resonant points can be adjusted to obtain a polarization selection unit operating at different frequencies.

[0040] In this embodiment, the dielectric substrate of the transmitting array multi-resonant structure antenna element is Rogers RO4003, and its dielectric constant ε r is 3.38. The thickness h1 of the upper dielectric substrate and the lower dielectric substrate is 0.813 mm, and the thickness h2 of the intermediate adhesive layer is 0.254 mm; the side length of the transmitting array antenna element is p = 6 mm. The length of the upper metasurface layer is a = 2.66 mm, the width is b = 2.42 mm, the chamfer length t = 0.726 mm, and the size of the etched C-shaped slot is c = d = 1.614 mm, l = 1 mm, w = 1.453 mm. The intermediate metal floor 5 is printed on the bottom surface of the upper dielectric substrate 4. Among them, the adhesive layer 6 uses Roger RO4450F, and its dielectric constant ε r = 3.5,

[0041] The size of the lower metasurface layer 8 is k 11 = 3.23 mm, k 12 = 1.41 mm, k 21 = 2.9 mm, k 22 = 1 mm, k 31 = 2.29 mm, k 32 = 0.258 mm, s = 0.27 mm. In this embodiment, the diameter d1 of the coaxial cylinder is 0.68 mm, and the diameter d2 of the circular through hole etched in the center of the intermediate metal ground layer is 0.8 mm.

[0042] Combined with Figure 8, in the Floquet mode, the energy in the Y polarization direction is simulated using the TE mode, and the energy in the X polarization direction is simulated using the TM mode. When the energy of the TE mode is incident on the low-profile broadband transmissive array antenna element based on the multi-resonant structure, it can be converted into the energy of the TM mode, and within the frequency band of 22 - 27 GHz, its -10 dB transmission bandwidth is 23.9%. In addition, the linearity of the curve of its transmission phase varying with frequency is also good. When the energy of the TM mode is incident on the polarization selector unit based on the multi-resonant structure, the energy cannot pass through the polarization selector and is all reflected back within the range of 22 - 27 GHz. At the center frequency of 25 GHz, its transmission phase varies linearly with the increase of frequency, and can achieve a phase change of more than 360 degrees, and the linearity with frequency change is good.

[0043] Combined with Figure 9 , within the frequency band of 22 - 27 GHz, the return loss coefficient of this transmissive array antenna is less than -10 dB.

[0044] Combined with Figure 10 , the sidelobe levels of the radiation pattern of this transmissive array antenna are all less than -18 dB. In addition, when theta = 0°, its cross-polarization levels are all less than -13 dB.

[0045] Combined with Figure 11 , at 24.5 GHz, this transmissive array antenna has the maximum gain of 25 dBi, its -1 dB gain bandwidth is 12.5%, and its -3 dB gain bandwidth is 25%.

[0046] Combined with Figure 12 , the -3 dB axial ratio bandwidth of this transmissive array antenna is 16%.

[0047] The specific implementation schemes described above have further elaborated on the purpose, technical solutions, and beneficial effects of the present invention. It should be understood that the above are only specific implementation schemes of the present invention, and are not intended to limit the scope of the present invention. Any equivalent changes and modifications made by those skilled in the art without departing from the concept and principles of the present invention shall fall within the scope of protection of the present invention.

Claims

1. A low-profile broadband transmissive array antenna based on a multi-resonant structure, characterized in that It includes a multi-resonant structure transmissive array surface and a polarization-rotation reflective surface; the multi-resonant structure transmissive array surface is arranged above the polarization-rotation reflective surface through a support frame; the multi-resonant structure transmissive array surface includes a plurality of multi-resonant structure antenna elements (1) arranged periodically; the multi-resonant structure antenna element (1) is a multi-layer stacked structure, which sequentially includes an upper metasurface layer (3), an upper dielectric substrate (4), an intermediate metal ground layer (5), an adhesive layer (6), a lower dielectric substrate (7), a lower metasurface layer (8) and a coaxial structure (9) for conducting electromagnetic energy; a circular through-hole is etched in the center of the intermediate metal ground layer (5); the polarization-rotation reflective surface includes a plurality of polarization-rotation reflective surface elements (2) arranged periodically, and the middle of the polarization-rotation reflective surface is hollowed out for placing a feed horn.

2. The low-profile broadband transmissive array antenna based on a multi-resonant structure according to claim 1, wherein The coaxial structure (9) is located at the geometric center of the multi-resonant structure antenna element (1) and is cylindrical in shape.

3. The low-profile broadband transmissive array antenna based on a multi-resonant structure according to claim 2, wherein The upper metasurface layer (3) is etched with C-shaped slits, and the lower metasurface layer (8) is a stepped rectangular metal patch.

4. The low-profile broadband transmissive array antenna based on a multi-resonant structure according to claim 3, wherein Both the upper metasurface layer (3) and the lower metasurface layer (8) include an upper polarization conversion patch and a lower polarization selection patch.

5. The low-profile broadband transmissive array antenna based on a multi-resonant structure according to claim 4, wherein The upper dielectric substrate (4) and the lower dielectric substrate (7) have the same thickness.

6. The low-profile broadband transmissive array antenna based on a multi-resonant structure according to claim 5, wherein The lower metasurface layer (8) is a multi-resonant structure formed by splicing three rectangular metal patches; the width of the middle rectangular metal patch is three times the width of the small rectangular metal patch, and the sum of the width of the middle rectangular metal patch and the width of the small rectangular metal patch is not greater than the width of the large rectangular metal patch.

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