Double-layer electric wall composite broadband SIW slot antenna based on metasurface

Abstract

The invention discloses a double-layer electric wall composite broadband SIW slot antenna based on a metasurface, which relates to the field of antennas, and comprises a dielectric substrate, a first radiating surface and a second radiating surface which are respectively arranged at the top and the bottom of the dielectric substrate, and a slot structure and a transition structure which are coplanar with the first radiating surface, and the double-layer electric wall structure is coplanar with the first radiating surface and the second radiating surface, and two layers of electric wall structures of the double-layer electric wall structure are different. The metal through holes of the antenna are replaced by the complementary resonance rings, transmission of electromagnetic waves in a channel is achieved by adopting the metasurface structure which is periodically arranged based on the magnetic resonance units on the radiating surface, and compared with an existing substrate integrated waveguide slot antenna, the complementary resonance rings replace the metal through holes, machining is easy, and cost is low.

Description

Technical Field

[0001] The present application relates to the field of antenna technology, and in particular to a double-layer electric wall composite broadband SIW slot antenna based on a metasurface. Background Art

[0002] Microwave antennas are mainly divided into end-fire, side-fire, slot antennas and other types. Among them, waveguide slot antennas have the advantages of narrow main lobe width, flexible beam scanning and large power capacity. The classic waveguide slot antenna cuts slots on the waveguide wall according to a certain pattern and radiates electromagnetic waves in a form similar to a dipole antenna. The substrate integrated waveguide slot antenna is based on the traditional metal waveguide slot antenna. It uses metal through holes in the dielectric substrate structure and the upper and lower metal surfaces to form a quasi-closed dielectric waveguide structure, realizes the classic metal waveguide function on the dielectric, and radiates electromagnetic waves through the slot. Compared with ordinary waveguide slot antennas, substrate integrated waveguide slot antennas retain the excellent transmission characteristics of dielectric waveguides, and at the same time have the advantages of small size, low profile, low cost, and are very easy to integrate with printed circuit boards. It has been widely used in communications, radars and other fields.

[0003] The easy integration of substrate-integrated waveguide slot antennas can realize the integrated design of antennas and circuits, and has further broad development prospects and more potential practical application value. However, as the communication frequency band develops to higher frequency bands such as millimeter waves, the volume of substrate-integrated waveguides is getting smaller and smaller, which puts higher requirements on the processing accuracy of metallized through holes and waveguide plane flattening technology. There are potential processing errors and local unevenness that lead to performance degradation such as antenna pattern distortion and bandwidth reduction; at the same time, in the integrated design of millimeter wave antennas and circuits, how to simultaneously achieve high-precision drilling, metal injection and PCB surface printing without affecting each other also brings higher processing costs. Therefore, it is still a difficult problem in engineering to realize small-sized substrate-integrated waveguide slot antennas with excellent radiation and bandwidth performance in higher frequency bands such as microwave millimeter waves. Existing studies mostly use the method of optimizing the stepped impedance transformer or optimizing the slot structure to improve the radiation or bandwidth performance of substrate-integrated waveguide slot antennas.

[0004] Chinese patent CN111416206A discloses a substrate integrated waveguide slot antenna, which improves impedance matching by setting a stepped impedance transformer between the feed line and the radiating surface, and introduces a radio frequency connector to optimize the feed line electrical connection method. Chinese patent CN110323569A discloses a substrate integrated waveguide back cavity hexagonal slot antenna, which improves the bandwidth and adjustability of the antenna by changing the back cavity slot to a hexagon. However, it has the following shortcomings: First, the relative bandwidth of the antenna is only 1.42%, and the working bandwidth is not greatly improved; second, the metallized through hole used is still a method of drilling through the dielectric substrate. When the frequency increases and the size decreases, there are problems such as complex process and high cost, which affects the antenna design performance at high working frequency when the process limit is reached. Summary of the invention

[0005] In order to solve the above technical problems, this application proposes the following technical solutions: In the first aspect, an embodiment of the present application provides a double-layer electric wall composite broadband SIW slot antenna based on a metasurface, comprising: a dielectric substrate, a first radiating surface and a second radiating surface respectively arranged on the top and bottom of the dielectric substrate, a slot structure and a transition structure coplanar with the first radiating surface, and a double-layer electric wall structure coplanar with the first radiating surface and the second radiating surface, wherein the two layers of the electric wall structures of the double-layer electric wall structure are different.

[0006] In a possible implementation, the transition structure is a trapezoidal structure coplanar with the first radiation surface, located symmetrically in the center of both sides of the first radiation surface, and the transition structure is connected to a microstrip line, and the transition structure is connected to a feed source through the microstrip line.

[0007] In a possible implementation manner, the slot structure is a periodic slot structure based on Floquet's theorem.

[0008] In a possible implementation manner, the units of the periodic slot structure include trapezoidal slots and single slots.

[0009] In a possible implementation, the double-layer electric wall structure includes a first resonant ring group coplanar with the first radiation surface and a second resonant ring group coplanar with the second radiation surface, the first resonant ring group and the second resonant ring group are both arranged on both sides of the radiation surface, and the resonant ring group realizes the transmission of electromagnetic waves emitted by the feed source inside the dielectric substrate surrounded by the electric walls on both sides, the first radiation surface and the second radiation surface.

[0010] In a possible implementation, each resonant ring group includes two groups of resonant rings with different structural forms, each resonant ring is composed of periodically arranged metal ring hollow microstructures, the metal ring hollow microstructures of the first resonant ring group are located on both sides of the gap structure, the metal ring hollow microstructures of the first resonant ring group and the second resonant ring group correspond to each other up and down, and the opening directions of the corresponding metal ring hollow microstructures of the first resonant ring group and the second resonant ring group are opposite.

[0011] In a possible implementation, the shapes of the metal ring hollow microstructure include: triangle and cross.

[0012] In a possible implementation manner, the resonant ring group includes a combination of a triangle and a cross, or a combination of a cross and a triangle.

[0013] In a possible implementation, the triangular metal ring hollow microstructure has a definition of an opening direction, which is an unclosed triangular base; the cross-shaped metal ring hollow microstructure is centrally symmetrical and has no definition of an opening direction; the opening direction of other types of metal ring hollow microstructures depends on whether they have an unclosed base. If there is an opening, the opening directions of the first resonant ring and the second resonant ring are opposite.

[0014] In a possible implementation manner, the dielectric substrate is a rectangular parallelepiped structure filled with dielectric.

[0015] In an embodiment of the present application, the metal through holes of the antenna are replaced with complementary resonant rings. By adopting a metasurface structure based on a periodic arrangement of magnetic resonance units on the radiating surface, the transmission of electromagnetic waves in the channel is realized. Compared with the existing substrate integrated waveguide slot antenna, the complementary resonant ring replaces the metal through hole, which is easy to process and low in cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 A schematic diagram of the structure of a double-layer electric wall composite broadband SIW slot antenna based on a metasurface provided in an embodiment of the present application, which includes a three-layer cross-sectional view, a top view, and a bottom view from top to bottom; Figure 2 A trapezoidal slot antenna of a triangle plus a cross-shaped combined resonant ring group provided in an embodiment of the present application; Figure 3 for Figure 2 S11 simulation diagram of the middle antenna; Figure 4 for Figure 2 The radiation pattern of the antenna in the figure; Figure 5 A cross-shaped and triangle-shaped combined resonant ring group trapezoidal slot antenna provided in an embodiment of the present application; Figure 6 for Figure 5S11 simulation diagram of the middle antenna; Figure 7 for Figure 5 The radiation pattern of the antenna in the figure; Figure 8 A single slot antenna of a triangular plus cross-shaped combined resonant ring group provided in an embodiment of the present application; Fig. 9 for Figure 8 S11 simulation diagram of the middle antenna; Fig.10 for Figure 8 The radiation pattern of the antenna in the figure; Fig.11 A cross-shaped plus triangle-shaped combined resonant ring group single slot antenna provided in an embodiment of the present application; Fig.12 for Fig.11 S11 simulation diagram of the middle antenna; Fig.13 for Fig.11 The radiation pattern of the antenna in the figure; Figure 1-13 In the symbol, it is represented as: 1- dielectric substrate, 2- first radiation surface, 3- second radiation surface, 4- slot structure, 5- transition structure, 6- electric wall structure, 7- microstrip line. DETAILED DESCRIPTION

[0017] The present solution is described below in conjunction with the accompanying drawings and specific implementation methods.

[0018] See also Figure 1 The double-layer electric wall composite broadband SIW slot antenna based on the metasurface provided in this embodiment includes: a dielectric substrate 1, which is a rectangular parallelepiped structure filled with dielectric. A first radiation surface 2 and a second radiation surface 3 are respectively arranged on the top and bottom of the dielectric substrate 1, a slot structure 4 and a transition structure 5 coplanar with the first radiation surface 2, and a double-layer electric wall structure 6 coplanar with the first radiation surface 2 and the second radiation surface 3, wherein the two layers of the double-layer electric wall structure 6 are different.

[0019] The transition structure 5 is a trapezoidal structure coplanar with the first radiation surface 2 , and is located symmetrically in the center of both sides of the first radiation surface 2 . The transition structure 5 is connected to a microstrip line 7 , and the transition structure 5 is connected to a feed source through the microstrip line 7 .

[0020] The slot structure 4 is a periodic slot structure 4 based on Floquet's theorem. In this embodiment, units of the periodic slot structure 4 include trapezoidal slots and single slots.

[0021] In this embodiment, the slot structure 4 must be a trapezoidal slot or a single slot as given in the embodiment, or it can be a single slot of other types, and the slot cannot be removed and changed to a transmission line design, because the electrical transmission characteristics of the double-layer electrical wall structure 6 cannot be well matched in the transmission line design and can only be used for antenna design.

[0022] Specifically, the double-layer electric wall structure 6 in this embodiment includes a first resonant ring group coplanar with the first radiation surface 2 and a second resonant ring group coplanar with the second radiation surface 3. The first resonant ring group and the second resonant ring group are both arranged on both sides of the radiation surface. The resonant ring group realizes the transmission of the electromagnetic waves emitted by the feed source inside the dielectric substrate 1 surrounded by the electric walls 6 on both sides, the first radiation surface 2 and the second radiation surface 3. Each resonant ring group includes two groups of resonant rings with different structural forms, each resonant ring is composed of periodically arranged metal ring hollow microstructures, the metal ring hollow microstructures of the first resonant ring group are located on both sides of the gap structure 4, the metal ring hollow microstructures of the first resonant ring group and the second resonant ring group correspond to each other up and down, and the opening directions of the metal ring hollow microstructures corresponding to the first resonant ring group and the second resonant ring group are opposite. The shapes of the metal ring hollow microstructures include: triangle and cross, and the resonant ring group includes a combination of triangle and cross, and a combination of cross and triangle.

[0023] The distance between each group of trapezoidal slots or single slots in the slot structure 4 ranges from 0.3 wavelengths to 1.2 wavelengths, and the number is M, where M is greater than or equal to 3. The number of M is positively correlated with the antenna gain, so the actual designed M value is related to the required gain index range.

[0024] The spacing between the adjacent and coplanar triangular and cross-shaped resonant rings on the same side of the first resonant ring group and the second resonant ring group of the double-layer electric wall structure 6, or the spacing between the adjacent and coplanar cross-shaped and triangular resonant rings on the same side, are all 0.01 wavelength to 0.40 wavelength. The spacing between the adjacent and coplanar triangular and triangular resonant rings on the same side, or the spacing between the adjacent and coplanar cross-shaped and cross-shaped resonant rings on the same side, are all 0.1 wavelength to 0.5 wavelength. The number of triangular and cross-shaped resonant rings in the first resonant ring group on the same side is N, respectively, and the number of triangular and cross-shaped resonant rings in the second resonant ring group on the same side is also N, respectively. The number of N is positively correlated with the value of M, and N is greater than M. At the same time, the degree to which N is greater than M requires ensuring that the first gap and the Mth gap in the gap structure 4, respectively, are in the range of 0.3 wavelength to 1.2 wavelength from the junction of the transition structure 5 and the first radiation surface 2.

[0025] Several double-layer electric wall composite broadband SIW slot antennas based on metasurfaces are described below by way of schematic examples.

[0026] See also Figure 2 , Figure 2 In the metasurface-based double-layer electric wall composite broadband SIW slot antenna, the unit of the periodic slot structure is a trapezoidal slot, and the resonant ring group is a combination of a triangle and a cross, with the triangle on the inside and the cross on the outside.

[0027] See also Figure 3 , Figure 3 The S11 results show that Figure 2 The reflection coefficient of the antenna at a specific frequency is extremely small (the influence of the inner triangular resonant ring), and the S11 value at 34.91 GHz is -57.74; at the same time, it has a certain broadband performance (the influence of the outer cross resonant ring), and the frequency range in which S11 is lower than -10 dB is 34.60 GHz-35.10 GHz, but at 33.50 GHz-34.60 GHz, it has an acceptable low reflection coefficient; the overall curve trend shows that the extremely low sharp low reflection coefficient is the main characteristic, and the bandwidth is widened to a certain extent.

[0028] See also Figure 4 , Figure 4 The E-plane directional diagram in Figure 2 The antenna achieves high-gain radiation performance, with a typical maximum gain of 11.9dBi at 35.0GHz, a main lobe direction of -38 degrees, and a 3dB beamwidth angle of 12.4 degrees.

[0029] See also Figure 5 , Figure 5 In the metasurface-based double-layer electric wall composite broadband SIW slot antenna, the unit of the periodic slot structure is a trapezoidal slot, and the resonant ring group is a combination of a cross and a triangle, with the cross on the inside and the triangle on the outside.

[0030] See also Figure 6 , Figure 6 The S11 results show that Figure 5 The antenna in the figure has significant broadband performance (the influence of the inner cross-shaped resonant ring). The frequency range in which S11 is below -10 dB is 33.36 GHz-37.50 GHz, and 38.20 GHz-41.26 GHz. The S11 value in the range of 37.50 GHz-38.20 GHz is around -9 dB, which is also an acceptably low reflection coefficient. At the same time, it brings a lower reflection coefficient at specific frequencies (the influence of the outer triangular resonant ring). For example, the S11 value at 36.50 GHz is -30.42 dB. The overall curve trend shows that the main characteristic is an extremely wide and flat broadband, and the reflection coefficient at specific frequencies is reduced to a certain extent.

[0031] See also Figure 7 , Figure 7 The E-plane directional diagram in Figure 5The antenna achieves high-gain radiation performance, with a typical maximum gain of 14.8dBi at 36.0 GHz, a main lobe direction of -46 degrees, and a 3dB beamwidth angle of 6.3 degrees.

[0032] See also Figure 8 , Figure 8 In the metasurface-based double-layer electric wall composite broadband SIW slot antenna, the unit of the periodic slot structure is a single slot, and the resonant ring group is a combination of a triangle and a cross, with the triangle on the inside and the cross on the outside.

[0033] In this embodiment, Figure 2 and Figure 8 In the antenna, the resonant ring group is a triangular resonant ring on the inside and a cross resonant ring on the outside. The inside plays a major role, and the outside plays a minor role. Figure 2 and Figure 8 The antennas in the system all exhibit extremely low reflection coefficients at specific frequencies, and the bandwidth is widened to a certain extent.

[0034] See also Fig. 9 , Fig. 9 The S11 results show that Figure 8 The reflection coefficient of the antenna at a specific frequency point is extremely small (the influence of the inner triangular resonant ring), and the S11 value at 36.56GHz is -43.05; at the same time, it has a certain broadband performance (the influence of the outer cross resonant ring), and the frequency range in which S11 is lower than -10 dB is 34.99GHz-37.83GHz; the overall curve trend shows an extremely low sharp low reflection coefficient as the main characteristic, and the bandwidth is widened to a certain extent.

[0035] See also Fig.10 , Fig.10 The E-plane directional diagram in Figure 8 The antenna achieves high-gain radiation performance, with a typical maximum gain of 17.0 dBi at 37.0 GHz, a main lobe direction of -39 degrees, and a 3dB beamwidth angle of 3.0 degrees.

[0036] See also Fig.11 , Fig.11 In the metasurface-based double-layer electric wall composite broadband SIW slot antenna, the unit of the periodic slot structure is a single slot, and the resonant ring group is a combination of a cross and a triangle, with the cross on the inside and the triangle on the outside.

[0037] In this embodiment, Figure 5 and Fig.11 In the antenna, the resonant ring group is a cross-shaped resonant ring on the inside and a triangular resonant ring on the outside. The inside plays a major role, and the outside plays a minor role. Figure 5 and Fig.11 The antennas in the system all exhibit extremely wide broadband performance, and the reflection coefficient at a specific frequency point is reduced to a certain extent.

[0038] Figure 2 and Figure 5 In the antenna, the units of the slot structure 4 are all trapezoidal slots. Figure 8 and Fig.11 In the antenna, the units of the slot structure 4 are all single slots. Both the trapezoidal slot and the single slot can achieve high-gain radiation performance, among which the trapezoidal slot design has lower side lobes, but the structure is more complicated; the single slot design has higher gain and simpler structure, but has higher side lobes.

[0039] See also Fig.12 , Fig.12 The S11 results show that Fig.11 The antenna has significant broadband performance (the influence of the inner cross-shaped resonant ring), and the frequency range where S11 is below -10 dB is 31.39GHz-38.10GHz; at the same time, it brings a lower reflection coefficient at specific frequencies (the influence of the outer triangular resonant ring), for example, the S11 value at 32.31GHz is -33.46dB; the overall curve trend shows an extremely wide and flat broadband as the main characteristic, and the reflection coefficient at specific frequencies is reduced to a certain extent.

[0040] See also Fig.13 , Fig.13 The E-plane directional diagram in Fig.11 The antenna achieves high-gain radiation performance, with a typical maximum gain of 17.30dBi at 37.0 GHz, a main lobe direction of 24 degrees, and a 3dB beamwidth angle of 2.8 degrees.

[0041] In the embodiments of the present application, "at least one" refers to one or more, and "plurality" refers to two or more. "And / or" describes the association relationship of associated objects, indicating that three relationships may exist. For example, A and / or B can represent the existence of A alone, the existence of A and B at the same time, and the existence of B alone. Among them, A and B can be singular or plural. The character " / " generally indicates that the previous and subsequent associated objects are in an "or" relationship. "At least one of the following" and similar expressions refer to any combination of these items, including any combination of single or plural items. For example, at least one of a, b and c can be represented by: a, b, c, ab, ac, bc, or abc, where a, b, c can be single or multiple.

[0042] The above is only a specific implementation of the present application. Any person skilled in the art can easily think of changes or substitutions within the technical scope disclosed in the present application, which should be included in the protection scope of the present application. The protection scope of the present application should be based on the protection scope of the claims.

Claims

1. A double-layer electric wall composite broadband SIW slot antenna based on a metasurface, characterized in that: include: A dielectric substrate, a first radiation surface and a second radiation surface respectively arranged on the top and bottom of the dielectric substrate, a gap structure and a transition structure coplanar with the first radiation surface, and a double-layer electric wall structure coplanar with the first radiation surface and the second radiation surface, wherein the two layers of the electric wall structure of the double-layer electric wall structure are different.

2. The double-layer electric wall composite broadband SIW slot antenna based on a metasurface according to claim 1, characterized in that: The transition structure is a trapezoidal structure coplanar with the first radiation surface, and is located symmetrically in the middle of both sides of the first radiation surface. The transition structure is connected to a microstrip line, and the transition structure is connected to a feed source through the microstrip line.

3. The double-layer electric wall composite broadband SIW slot antenna based on a metasurface according to claim 2, characterized in that: The slot structure is a periodic slot structure based on Floquet's theorem.

4. The double-layer electric wall composite broadband SIW slot antenna based on a metasurface according to claim 3, characterized in that: The units of the periodic slot structure include trapezoidal slots and single slots.

5. The double-layer electric wall composite broadband SIW slot antenna based on a metasurface according to claim 1, characterized in that: The double-layer electric wall structure includes a first resonant ring group coplanar with the first radiation surface and a second resonant ring group coplanar with the second radiation surface. The first resonant ring group and the second resonant ring group are both arranged on both sides of the radiation surface. The resonant ring group realizes the transmission of electromagnetic waves emitted by the feed source inside the dielectric substrate surrounded by the electric walls on both sides, the first radiation surface and the second radiation surface.

6. The double-layer electric wall composite broadband SIW slot antenna based on a metasurface according to claim 5, characterized in that: Each resonant ring group includes two groups of resonant rings with different structural forms, each resonant ring is composed of periodically arranged metal ring hollow microstructures, the metal ring hollow microstructures of the first resonant ring group are located on both sides of the gap structure, the metal ring hollow microstructures of the first resonant ring group and the second resonant ring group correspond to each other up and down, and the opening directions of the metal ring hollow microstructures corresponding to the upper and lower parts of the first resonant ring group and the second resonant ring group are opposite.

7. The double-layer electric wall composite broadband SIW slot antenna based on a metasurface according to claim 6, characterized in that: The shapes of the metal ring hollow microstructure include: triangle and cross.

8. The double-layer electric wall composite broadband SIW slot antenna based on a metasurface according to claim 7, characterized in that: The resonant ring group includes a combination of a triangle and a cross, and a combination of a cross and a triangle.

9. The double-layer electric wall composite broadband SIW slot antenna based on a metasurface according to claim 1, characterized in that: The dielectric substrate is a rectangular parallelepiped structure filled with dielectric.

Images