Low-profile dual-frequency dual-polarization high-gain metasurface antenna with double-layer metasurface structure

Abstract

The present invention discloses a low-profile dual-frequency dual-polarization high-gain metasurface antenna with a double-layer metasurface structure, comprising a microstrip feeding structure, a bottom dielectric substrate, a metal grounding plate and a double-layer metasurface structure stacked in sequence; the double-layer metasurface structure comprises a middle dielectric plate, a lower metasurface, an air loading layer, a top dielectric plate and an upper metasurface stacked in sequence. The present invention designs a multi-layer metasurface structure, combines loading gaps and a reasonable feeding structure, and finally realizes a low-profile dual-frequency dual-polarization high-gain metasurface antenna with a double-layer metasurface structure having low profile, dual broadband, high isolation and high gain characteristics.

Description

Technical Field

[0001] The present invention belongs to the technical field of wireless communications, and more specifically, relates to a low-profile dual-frequency dual-polarization high-gain supersurface antenna with a double-layer supersurface structure. Background Art

[0002] At present, the 2G / 3G / LTE communication system has covered the 0.69-0.96GHz and 1.7-2.7GHz frequency bands. The 5G frequency bands allocated by my country's four major operators have covered the 2.515-2.675GHz and 3.3-3.6GHz frequency bands. At the same time, the 4.8-5.0GHz frequency band is also allocated as a backup frequency band for my country's 5G communication system. In addition to the mobile communication frequency band, wireless local area networks and global Internet access networks also occupy the 2.4-2.7GHz and 5.15-5.85GHz frequency bands. It can be seen that in order to meet the needs of various fields without occupying additional antenna resources, the multi-frequency base station antenna is of great significance.

[0003] Single-antenna multi-frequency technology has only one radiator, and the overall structure is relatively compact. However, due to the different number of antennas and unit spacing required for antenna arrays in different frequency bands, it is difficult for this type of antenna to form a large-scale multi-frequency array. For outdoor macro base stations, high gain and wide coverage are required. Dual-band or multi-band applications require compact size, low cost, low mass, high aperture utilization, and easy integration. Therefore, multi-antenna multi-frequency systems are more suitable, and it is easier to achieve dual-polarization performance using a multi-antenna system.

[0004] At present, many researchers have used dipole antenna co-aperture technology to achieve multi-frequency broadband coverage, but this technology has certain limitations, such as low gain and high height. In recent years, researchers have found that metasurface antennas can achieve broadband and high gain while maintaining a very compact size, making metasurface antennas a research hotspot in recent years. Therefore, it is of great significance to use the advantages of metasurface antennas to design base station antennas. Summary of the invention

[0005] In order to solve at least one of the above technical problems, according to one aspect of the present invention, a low-profile dual-frequency dual-polarization high-gain metasurface antenna with a double-layer metasurface structure is provided, comprising:

[0006] A microstrip feeding structure, a bottom dielectric substrate, a metal ground plate and a double-layer metasurface structure are sequentially stacked;

[0007] The double-layer supersurface structure includes a middle dielectric plate, a lower supersurface, an air-loaded layer, a top dielectric plate and an upper supersurface which are stacked in sequence.

[0008] Further, the lower layer super surface includes a central patch, a first rectangular loading patch, a second rectangular loading patch, a third rectangular loading patch and a fourth rectangular loading patch;

[0009] The central patch is located at the exact center of the bottom dielectric substrate, and the first rectangular loading patch, the second rectangular loading patch, the third rectangular loading patch and the fourth rectangular loading patch are placed around the central patch;

[0010] The distance between the first rectangular loading patch and the central patch is g3, and the distance between the second rectangular loading patch, the third rectangular loading patch and the fourth rectangular loading patch and the central patch is g2.

[0011] Furthermore, the metal ground plate is etched with 6 slots, namely: a first I-type feeding slot, a second I-type feeding slot, a first rectangular loading slot, a second rectangular loading slot, a third rectangular loading slot and a fourth rectangular loading slot;

[0012] The first I-type feeding slot and the second I-type feeding slot are of different sizes and perpendicular to each other, and are respectively etched on both sides of the center position of the metal floor;

[0013] The first I-type feeding slot is used to excite a vertically polarized radiation mode;

[0014] The second I-type feeding slot is used to excite a horizontally polarized radiation mode;

[0015] The first rectangular loading slot, the second rectangular loading slot, the third rectangular loading slot and the fourth rectangular loading slot are respectively etched around the first I-type feeding slot and the second I-type feeding slot.

[0016] Furthermore, the etching positions of the first rectangular loading gap, the second rectangular loading gap, the third rectangular loading gap and the fourth rectangular loading gap are respectively located directly below the first rectangular loading patch, the second rectangular loading patch, the third rectangular loading patch and the fourth rectangular loading patch of the lower super surface.

[0017] Furthermore, the microstrip feeding structure is composed of a first Y-type microstrip feed line and a second Y-type feed line, wherein the first Y-type microstrip feed line is located directly below the first I-type feeding slot, and the second Y-type feed line is located directly below the second I-type feeding slot, respectively controlling the vertical and horizontal polarization radiation modes.

[0018] Furthermore, the first Y-shaped microstrip feed line is loaded with a bridge structure and is bent at the end.

[0019] Compared with the prior art, the present invention has at least the following beneficial effects:

[0020] The present invention has low profile, dual broadband, high isolation and high gain characteristics, and can easily achieve stable dual-polarization directional radiation performance in two 5G frequency bands. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings of the embodiments will be briefly introduced below. Obviously, the drawings in the following description only relate to some embodiments of the present invention, but are not intended to limit the present invention.

[0022] Figure 1 A schematic structural cross-sectional view of an embodiment of a low-profile dual-frequency dual-polarization high-gain metasurface antenna of a double-layer metasurface structure of the present invention;

[0023] Figure 2 A schematic structural diagram of an embodiment of a low-profile dual-frequency dual-polarization high-gain metasurface antenna of a double-layer metasurface structure of the present invention;

[0024] Figure 3 A schematic diagram of the upper metasurface structure of an embodiment of a low-profile dual-frequency dual-polarization high-gain metasurface antenna of a double-layer metasurface structure of the present invention;

[0025] Figure 4 A schematic diagram of the lower metasurface structure of an embodiment of a low-profile dual-frequency dual-polarization high-gain metasurface antenna of a double-layer metasurface structure of the present invention;

[0026] Figure 5 A schematic diagram of the metal ground plate structure of an embodiment of a low-profile dual-frequency dual-polarization high-gain metasurface antenna of a double-layer metasurface structure of the present invention;

[0027] Figure 6 A schematic diagram of a microstrip feeding structure of an embodiment of a low-profile dual-frequency dual-polarization high-gain metasurface antenna of a double-layer metasurface structure of the present invention;

[0028] Figure 7 The S parameters (S11, S22 and S21) of the two ports of the low-profile dual-frequency dual-polarization high-gain metasurface antenna embodiment of the double-layer metasurface structure of the present invention;

[0029] Figure 8 It is the positive z-direction gain of two polarization modes of the low-profile dual-frequency dual-polarization high-gain supersurface antenna embodiment of the double-layer supersurface structure of the present invention.

[0030] Fig. 9 The radiation patterns of the H-plane and E-plane of the two polarization modes of the low-profile dual-frequency dual-polarization high-gain metasurface antenna embodiment of the double-layer metasurface structure of the present invention are shown at 2.5 GHz, 2.75 GHz, 3.32 GHz and 3.61 GHz. DETAILED DESCRIPTION

[0031] To make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution of the embodiments of the present invention will be described clearly and completely in conjunction with the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them.

[0032] Unless otherwise defined, technical or scientific terms used herein shall have the same meaning as commonly understood by one of ordinary skill in the art to which the invention belongs.

[0033] Embodiment 1:

[0034] This embodiment provides a low-profile dual-frequency dual-polarization high-gain metasurface antenna with a double-layer metasurface structure. All stacked structures are fixed by nylon screws and nylon studs through 4 screw holes, which is very convenient.

[0035] In this embodiment, the overall structure of the antenna is as follows: Figure 1 The antenna is in a square shape as a whole, and comprises: a microstrip feeding structure (8), a bottom dielectric substrate (7), a metal grounding plate (6), and a double-layer metasurface structure stacked from bottom to top; wherein the double-layer metasurface structure comprises a middle dielectric plate (5), a lower metasurface (4), an air loading layer (3), a top dielectric plate (2), and an upper metasurface (1).

[0036] In this embodiment, the side length of all dielectric plates is L=100mm, wherein the top dielectric plate (2) is made of F4BM350 plate with a dielectric constant of 3.5 and a thickness of H1=0.5mm; the middle dielectric plate (5) is made of F4BM220 plate with a dielectric constant of 2.2 and a thickness of H2=1.5mm; the bottom dielectric plate (7) is made of F4BM350 plate with a dielectric constant of 3.5 and a thickness of H3=0.5mm; the thickness of the air loading layer (3) is Ha=4mm. The overall thickness of the antenna is 6.5mm (0.053 times the wavelength of the lowest operating frequency), which has the advantage of a low profile, and the thickness parameter can be appropriately adjusted according to the application.

[0037] The upper layer super surface structure of this embodiment is as follows Figure 3 As shown, a total of 16 evenly arranged square patches with a side length of D1 = 18 mm are included, and the spacing between adjacent square patches is g1 = 0.6 mm.

[0038] The lower layer super surface structure of this embodiment is as follows Figure 4As shown, it is composed of a central patch (9) and a first rectangular loading patch (10-1), a second rectangular loading patch (10-2), a third rectangular loading patch (10-3) and a fourth rectangular loading patch (10-4); and the first rectangular loading patch (10-1), the second rectangular loading patch (10-2), the third rectangular loading patch (10-3) and the fourth rectangular loading patch (10-4) are respectively placed around the central patch (9), wherein the distance between the first rectangular loading patch (10-1) and the central patch (9) is g3, and the distance between the second rectangular loading patch (10-2), the third rectangular loading patch (10-3) and the fourth rectangular loading patch (10-4) is g4. The distance between the loading patch (10-4) and the center patch (9) is g2; the values ​​of g2 and g3 will affect the impedance matching of the antenna, and a larger value of g3 than g2 can reduce the deflection of the directional pattern caused by the offset center of the I-type feeding slot (11-2); the length and width of the center patch (9) are D2=29mm and D3=28mm respectively; the length and width of the first rectangular loading patch (10-1) and the third rectangular loading patch (10-3) are D2=29mm and W2=18mm respectively; the length and width of the second rectangular loading patch (10-2) and the fourth rectangular loading patch (10-4) are D3=28mm and W3=18mm respectively.

[0039] The metal ground plate structure of this embodiment is as follows Figure 5 As shown, a total of 6 slots are etched, wherein the first I-type feeding slot (11-1) and the second I-type feeding slot (11-2) have different sizes and are perpendicular to each other, and are respectively etched on both sides of the center position of the metal floor (6). The center of the first I-type feeding slot (11-1) deviates from the center position by Dv2, and the center of the second I-type feeding slot (11-2) deviates from the center position by Dv1. The deviation can make the first I-type feeding slot (11-1) and the second I-type feeding slot (11-2) both located below the center patch (9) and will not overlap. Changing the offset distances Dv1 and Dv2 will have a certain impact on the impedance matching of the antenna; wherein the first I-type feeding slot (11-1) is used to excite the vertical polarization radiation mode, and the second I-type feeding slot (11-2) is used to excite the vertical polarization radiation mode. The I-type feeding slot (11-2) is used to excite the horizontal polarization radiation mode; in addition, the first rectangular loading slot (12-1), the second rectangular loading slot (12-2), the third rectangular loading slot (12-3) and the fourth rectangular loading slot (12-4) are respectively etched around the first I-type feeding slot (11-1) and the second I-type feeding slot (11-2); the etching positions of the rectangular loading slots (12-1, 12-2, 12-3, 12-4) are respectively correspondingly distributed directly below the lower layer metasurface rectangular loading patches (10-1, 10-2, 10-2, 10-3), which can effectively enhance the coupling between the excitation structure and the metasurface structure, so that the metasurface structure can better exert its structural advantages to achieve higher gain.

[0040] The microstrip feeding structure of this embodiment is as follows Figure 6 As shown, the microstrip feeding structure (8) is composed of a first Y-type microstrip feed line (13-1) and a second Y-type feed line (13-2), wherein the first Y-type microstrip feed line (13-1) is located directly below the first I-type feed slot, and the second Y-type feed line (13-2) is located directly below the second I-type feed slot (11-2), respectively controlling vertical and horizontal polarization radiation modes, wherein the first Y-type microstrip feed line (13-1) is loaded with a bridge structure (14) and is bent at the end; the bridge structure can effectively suppress the resonance between the feed lines and improve the isolation between the ports. Two pads (15) are arranged on both sides of each group of microstrip feed lines, and the pads are connected to the metal ground plate through metallized through holes to facilitate welding of the SMA interface.

[0041] The S parameters of the two ports of this embodiment are as follows: Figure 7 As shown, it can be seen that in the range of 2.46-2.83GHz and 3.22-3.72GHz, the return loss of the two ports of the antenna is less than -10dB, and the two polarization mode ports are well matched, which can fully cover the two 5G frequency bands of 2.515-2.675GHz and 3.3-3.6GHz. At the same time, in the range of 2.46-2.83GHz, S21<-40dB, in the range of 3.22-3.72GHz, S21<-50dB, and both ports have high port isolation.

[0042] The gains in the positive z direction of the two polarized radiation modes of the antenna in this embodiment are as follows: Figure 8 As shown, in the range of 2.46-2.83GHz, the gains of the two polarized radiation modes in the positive z direction are both greater than 8.4dBi, and the maximum gain can reach 9.88dBi; in the range of 3.22-3.72GHz, the gains of the two polarized radiation modes in the positive z direction are both greater than 9.12dBi, and the maximum gain can reach 11.85dBi. It can be seen that the antenna has good directional radiation effect and high gain.

[0043] like Fig. 9 The figure shows the radiation patterns of the H plane and E plane of the two polarization modes when the antenna of this embodiment works at 2.5 GHz, 2.75 GHz, 3.32 GHz and 3.61 GHz. It can be seen that the two polarization modes have a stable directional radiation effect within the working bandwidth.

[0044] The examples described in the present invention are merely descriptions of the preferred implementation modes of the present invention, and are not intended to limit the concept and scope of the present invention. Without departing from the design concept of the present invention, various modifications and improvements made to the technical solutions of the present invention by engineers and technicians in this field should all fall within the protection scope of the present invention.

Claims

1. A low-profile dual-frequency dual-polarization high-gain metasurface antenna with a double-layer metasurface structure, characterized in that: include: A microstrip feeding structure, a bottom dielectric substrate, a metal ground plate and a double-layer metasurface structure are sequentially stacked; The double-layer supersurface structure comprises a middle-layer dielectric plate, a lower-layer supersurface, an air-loaded layer, a top-layer dielectric plate and an upper-layer supersurface which are stacked in sequence; The lower layer super surface includes a central patch, a first rectangular loading patch, a second rectangular loading patch, a third rectangular loading patch and a fourth rectangular loading patch; The central patch is located at the exact center of the bottom dielectric substrate, and the first rectangular loading patch, the second rectangular loading patch, the third rectangular loading patch and the fourth rectangular loading patch are placed around the central patch; The distance between the first rectangular loading patch and the central patch is g3, and the distance between the second rectangular loading patch, the third rectangular loading patch and the fourth rectangular loading patch and the central patch is g2; The metal ground plate is etched with 6 slots, which are: a first I-type feeding slot, a second I-type feeding slot, a first rectangular loading slot, a second rectangular loading slot, a third rectangular loading slot and a fourth rectangular loading slot; Wherein, the first I-type feeding slot and the second I-type feeding slot have different sizes and are perpendicular to each other, and are respectively etched on both sides of the center position of the metal ground plate; The first I-type feeding slot is used to excite a vertically polarized radiation mode; The second I-type feeding slot is used to excite a horizontally polarized radiation mode; The first rectangular loading slot, the second rectangular loading slot, the third rectangular loading slot and the fourth rectangular loading slot are respectively etched around the first I-type feeding slot and the second I-type feeding slot; The microstrip feeding structure is composed of a first Y-type microstrip feed line and a second Y-type feed line, wherein the first Y-type microstrip feed line is located directly below the first I-type feeding slot, and the second Y-type feed line is located directly below the second I-type feeding slot, respectively controlling vertical and horizontal polarization radiation modes.

2. The antenna according to claim 1, characterized in that The etching positions of the first rectangular loading gap, the second rectangular loading gap, the third rectangular loading gap and the fourth rectangular loading gap are respectively located directly below the first rectangular loading patch, the second rectangular loading patch, the third rectangular loading patch and the fourth rectangular loading patch of the lower super surface.

3. The antenna according to claim 1, characterized in that The first Y-shaped microstrip feed line is loaded with a bridge structure and is bent at the end.

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