A metasurface dipole antenna with improved high-order mode radiation characteristics

Abstract

The present invention discloses a metasurface dipole antenna with improved high-order mode radiation characteristics, comprising two dielectric substrates and three metal layers, wherein the three metal layers are metal strata, non-uniform metasurface layers and dipole layers from bottom to top, the non-uniform metasurface layers and dipole layers are respectively covered on the entire dielectric substrate, and the non-uniform metasurface layers are composed of non-uniform metal patches. The present invention suppresses high-order modes by improving the metasurface structure, improves high-frequency radiation characteristics, suppresses distortion of high-order mode patterns, maintains good broadside radiation performance in high-frequency bands, and has a wider impedance bandwidth; the gain is higher, and the gain of the working frequency band is relatively stable; in addition, the antenna has a simple structure, a small size, is easy to manufacture, and has a low cost.

Description

Technical Field

[0001] The invention relates to antenna technology, in particular to a metasurface dipole antenna with improved high-order mode radiation characteristics. Background Art

[0002] In recent years, with the rapid development of mobile communications, metasurface structures have been widely explored to enhance performance. Compared with traditional antennas, metasurface antennas have the advantages of low loss, low profile and wide bandwidth. Nowadays, metasurface antennas have many forms to achieve wide bandwidth, such as expanding bandwidth by slotting to excite the ground plane coupling aperture, expanding bandwidth by simultaneously exciting dipoles and metasurface surface waves, and expanding bandwidth by exciting TM leakage waves and TE surface waves through L-type probes. However, existing metasurface antennas have ignored the adverse effects of higher-order modes at higher operating frequencies. Higher-order modes will cause problems such as directional pattern distortion and gain reduction, resulting in a reduction in the actual working bandwidth. Summary of the invention

[0003] Purpose of the invention: In view of the above problems, the purpose of the present invention is to provide a metasurface dipole antenna with improved high-order mode radiation characteristics.

[0004] Technical solution: The present invention provides a metasurface dipole antenna with improved high-order mode radiation characteristics, comprising two dielectric substrates and three metal layers, wherein the three metal layers are, from bottom to top, a metal stratum, a non-uniform metasurface layer and a dipole layer, wherein the non-uniform metasurface layer and the dipole layer are respectively covered on the entire dielectric substrate, and the non-uniform metasurface layer is composed of a non-uniform metal patch.

[0005] Further, the non-uniform metasurface layer includes rectangular patches and square patches.

[0006] Furthermore, the non-uniform metasurface layer is composed of a group of n×n metal patch arrays, the central four units are rectangular patches, and the remaining units are square patches, where n is an even number greater than 5.

[0007] Furthermore, the side length of the square patch is W1, and the length of the rectangular patch is L1 and the width is W1.

[0008] Beneficial effects: Compared with the prior art, the present invention has the following significant advantages:

[0009] The present invention suppresses high-order modes and improves high-frequency radiation characteristics by improving the metasurface structure. Experimental results show that after using the improved antenna structure of the present invention, its bandwidth, gain, and radiation pattern are all improved, the distortion of the high-order mode radiation pattern is suppressed, and good wide-edge radiation performance is maintained in the high-frequency band; it has a wider impedance bandwidth; the gain is higher, and the gain of the working frequency band is relatively stable; in addition, the antenna has a simple structure, a small size, is easy to manufacture, and has a low cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 A schematic diagram of a layered structure of a metasurface dipole antenna for improving high-order mode radiation characteristics in an embodiment;

[0011] Figure 2 Schematic diagram of the layered structure of a traditional metasurface dipole antenna;

[0012] Figure 3 Schematic diagram of the metasurface layer structure of a traditional metasurface dipole antenna;

[0013] Figure 4 Schematic diagram of the improved super surface layer structure in the embodiment;

[0014] Figure 5 is the top view of the dipole;

[0015] Figure 6 Current distribution diagram of higher-order modes under eigenmode analysis of traditional metasurface dipole antenna;

[0016] Figure 7 It is a current distribution diagram of a higher-order mode under characteristic mode analysis of the improved metasurface dipole antenna in the embodiment;

[0017] Figure 8 Analyze the radiation patterns of higher-order modes for the eigenmodes of conventional metasurface dipole antennas;

[0018] Fig. 9 The directional diagram of the higher-order mode under the characteristic mode analysis of the improved metasurface dipole antenna in the embodiment;

[0019] Fig.10 This is a comparison chart of the reflection coefficients of the two structures under full-wave simulation;

[0020] Fig.11 This is a comparison of the radiation characteristics of the high-order modes of the two structures in the xz plane under full-wave simulation;

[0021] Fig.12 This is a comparison of the radiation characteristics of the high-order modes of the two structures in the yz plane under full-wave simulation;

[0022] Fig.13 This is a comparison chart of the two structure gains under full-wave simulation. DETAILED DESCRIPTION

[0023] In order to make the objectives, technical solutions and advantages of the present application more clearly understood, the present application is further described in detail below in conjunction with the accompanying drawings and embodiments.

[0024] The metasurface dipole antenna with improved high-order mode radiation characteristics described in this embodiment has a layered structure schematic diagram as shown in FIG. Figure 1The antenna comprises two dielectric substrates and three metal layers, wherein the three metal layers are, from bottom to top, a metal stratum, a non-uniform super-surface layer and a dipole layer, the non-uniform super-surface layer and the dipole layer are respectively covered on the entire dielectric substrate, and the non-uniform super-surface layer is composed of a non-uniform metal patch.

[0025] Furthermore, the non-uniform metasurface layer includes rectangular patches and square patches.

[0026] Furthermore, the non-uniform metasurface layer is composed of a group of n×n metal patch arrays, the central four units are rectangular patches, and the remaining units are square patches, where n is an even number greater than 5.

[0027] Furthermore, the side length of the square patch is W1, and the length and width of the rectangular patch are L1 and W1.

[0028] In one example, if Figure 1 The schematic diagram of the layered structure of the antenna of the present embodiment is shown. The metasurface dipole antenna comprises, from bottom to top, a metal ground layer, a lower dielectric substrate, a non-uniform metasurface layer, an upper dielectric substrate and a dipole layer. Both the upper dielectric substrate and the lower dielectric substrate adopt F4B substrates. The thickness of the lower F4B substrate is 3.048 mm, and the thickness of the upper F4B substrate is 1.6 mm. The grounding metal is printed below the lower dielectric substrate, and the dipole is printed on the upper layer of the upper dielectric substrate.

[0029] like Figure 2 As shown in the figure, the traditional metasurface dipole antenna consists of two layers of dielectric substrate and three layers of metal structure. The metasurface layer of the traditional metasurface dipole antenna is composed of uniform metal patches, which will cause the radiation pattern distortion due to the excitation of high-order modes at high frequencies. In this example, a 6×6 patch array is selected for comparison. Figure 3 As shown in , the metasurface layer of the traditional metasurface dipole antenna is a uniform 6×6 patch array, the unit is a square patch with a side length of W1, and the gaps between each unit in the X and Y directions are GX and GY respectively. Figure 4 As shown, the improved metasurface layer of the antenna of the present invention is a non-uniform 6×6 patch array, which is different from the traditional structure metasurface layer in that the four central units are rectangular patches with a length of L1 and a width of W1, while the remaining units are still square patches with a side length of W1, and the gaps between the units in the X and Y directions of the non-uniform metasurface layer are still GX and GY. The present invention proposes that the use of a non-uniform metasurface layer through the four central rectangular patches can improve the radiation characteristics of the metasurface high-order mode, so that the antenna still maintains good wide-side radiation characteristics at high frequencies, thereby expanding the impedance bandwidth of the antenna.

[0030] Figure 5The top view of the dipole layer is located above the upper dielectric substrate. The dipole layer is a pair of planar dipole antennas. While radiating itself, it also acts as an excitation source to feed the super surface layer, stimulating additional surface wave radiation modes, which will expand the antenna working bandwidth. The dipoles are symmetrical about the center of the substrate. The gap between the dipoles is D, the length of the dipole is L3, the width is W3, and the side length of the upper dielectric substrate is WP. In this example, the specific parameters of the antenna are as follows: WP = 50mm, W1 = 5.2mm, L1 = 7.8mm, W3 = 2.2mm, L3 = 8.1mm, D = 0.3mm, GX = 0.72mm, GY = 0.72mm.

[0031] Figure 6-Figure 9 The current distribution and radiation characteristics of the traditional metasurface dipole antenna structure and the improved metasurface dipole antenna structure of this embodiment under characteristic mode analysis at 7.8GHz and 7.3GHz respectively are shown. The surface current of the traditional structure is stronger at the edge of the array and weaker at the center, and the center current is opposite to the edge current, resulting in a narrow main lobe beam width, a large side lobe, a distorted pattern, and poor radiation characteristics. In this embodiment, by changing the length of the central unit, the surface current at the center is increased, the main lobe beam width is significantly improved, and more importantly, the side lobe level is significantly reduced, and the radiation characteristics are greatly improved.

[0032] Fig.10 A comparison chart of reflection coefficients of the traditional structure and the improved antenna of this embodiment under full-wave simulation is shown. The operating frequency band of the traditional structure is 4.5-6.24 (29%), and high-order modes appear at 7.78 GHz, which hinders the expansion of the bandwidth. The improved structure of this embodiment suppresses unnecessary high-order radiation modes, thereby improving the radiation pattern and achieving an impedance bandwidth of 4.33-7.09 GHz (46%).

[0033] Fig.11 and Fig.12 A comparison diagram of the radiation characteristics of the traditional structure and the improved structure under full-wave simulation is shown. In the xz plane, the traditional structure has a narrow main lobe beam width, a large side lobe, and poor radiation characteristics. The improved structure in this embodiment has an increased main lobe beam width, significantly reduced side lobes, and improved radiation characteristics. In the yz plane, the improved structure in this embodiment also has a wider main lobe beam width, reduced side lobes, and improved radiation characteristics, which is consistent with the characteristic mode analysis results.

[0034] Fig.13The radiation gain of the traditional structure and the improved structure in this embodiment is demonstrated under full-wave simulation. It can be seen that due to the improvement of high-order radiation characteristics, the gain of the improved antenna is greater than that of the traditional structure within the working frequency band. The peak gain of the traditional structure is 8.83dBi, and the peak gain of the improved structure is 11.58dBi, which is 2.75dB higher than that of the traditional structure.

Claims

1. A metasurface dipole antenna with improved high-order mode radiation characteristics, characterized in that: It includes two dielectric substrates and three metal layers, the three metal layers are metal stratum, non-uniform super surface layer and dipole layer from bottom to top, the non-uniform super surface layer and dipole layer are respectively covered on the whole dielectric substrate, and the non-uniform super surface layer is composed of non-uniform metal patches; The non-uniform supersurface layer consists of a group of n×n The non-uniform metasurface layer includes rectangular patches and square patches. The four central units are rectangular patches, and the remaining units are square patches. n is an even number greater than 5; The side length of the square patch is W1, and the length of the rectangular patch is L1 and the width is W1; The dipole layer is a pair of planar dipole antennas, which radiate themselves and serve as an excitation source to feed the non-uniform metasurface layer, thereby stimulating additional surface wave radiation modes. The dipoles are symmetrical about the center of the substrate. The gaps between the metal patches in the non-uniform super surface layer in the X and Y directions are equal.

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