Miniaturized metasurface antenna

Abstract

The application discloses a miniaturized metasurface antenna, which comprises three layers, namely a radiation layer, an air layer and a feed layer from top to bottom, wherein the radiation layer is provided with a metasurface radiation structure, and the feed layer is a microstrip line slot coupling feed structure; the metasurface radiation structure is composed of 16 square patches arranged in a 4*4 array, wherein a rectangular slot is loaded at the center of each square patch, and a branch is loaded at four corners; the metasurface radiation structure adjusts the equivalent capacitance of the metasurface antenna by changing the length and width of the loaded branch extending into the square patch; and the length of the current of the metasurface antenna is adjusted by changing the length and width of the rectangular slot. Compared with the existing conventional metasurface antenna, the metasurface antenna has the advantages of ensuring a wide impedance bandwidth and high gain of the metasurface antenna in the process of miniaturization.

Description

Technical Field

[0001] This invention belongs to the field of antenna technology, and specifically relates to a miniaturized metasurface antenna. Background Technology

[0002] With the rapid development of antenna technology in recent years, metasurface antennas have attracted widespread attention due to their high gain, wide bandwidth, and low profile characteristics caused by their special electromagnetic structure.

[0003] Compared to traditional microstrip patch antennas, metasurface antennas offer advantages such as wide bandwidth and high gain, but their overall size is relatively large. A problem with conventional metasurface antennas is that their size is generally larger than half a wavelength, making them unsuitable for antenna arrays. Therefore, miniaturization of metasurface antennas is of significant research importance.

[0004] For example, in IEEE, journal number TAP.2015.2429741, the article titled "Metamaterial-Based Low-Profile Broadband Aperture-Coupled Grid-Slotted Patch Antenna" is authored by W. Liu, ZN Chen, and X. Qing. The article describes a metamaterial-based antenna that simultaneously excites two adjacent resonant modes, exhibiting excellent impedance bandwidth and high radiation gain. However, its shortcomings are also obvious: the antenna is relatively large, with a wavelength of 0.72. Summary of the Invention

[0005] The purpose of this invention is to provide a miniaturized metasurface antenna that uses a metasurface structure of a square patch with loaded stubs and rectangular slots as the radiating element and a microstrip line slot-coupled feeding structure as the excitation method.

[0006] The technical solution to achieve the purpose of this invention is as follows:

[0007] A miniaturized metasurface antenna comprises three layers: an upper radiating layer, a middle air layer, and a bottom feed layer. A metasurface radiating structure is disposed on the radiating layer, and the feed layer is a microstrip line slot-coupled feed structure. The metasurface radiating structure consists of 16 square patches arranged in a 4×4 pattern. A rectangular slot is loaded at the center of each square patch, and stubs are loaded at the four corners. The equivalent capacitance of the metasurface antenna is adjusted by changing the length and width of the loaded stubs extending into the square patches. The current length of the metasurface antenna is adjusted by changing the length and width of the rectangular slots.

[0008] In a preferred embodiment of the technical solution of the present invention, the maximum length of the inserted branch can be increased by inserting the branch at a right angle through the square patch.

[0009] In a preferred embodiment of the present invention, the angle at which the branch is inserted is 45°, so that the maximum length of the branch that can be inserted is maximized.

[0010] In a preferred embodiment of the present invention, the microstrip line slot-coupled feeding structure is a bottom dielectric substrate, the upper surface of the bottom dielectric substrate is a metal ground plane, a coupling feeding slot is etched in the middle of the metal ground plane, and the lower surface of the bottom dielectric substrate is a microstrip line. The metasurface antenna is fed by the microstrip line slot-coupled feeding structure. The coupling degree between the metasurface antenna and the coupling feeding slot is adjusted by adjusting the extension length of the loaded stub relative to the coupling feeding slot. The length and width of the coupling feeding slot are adjustable to adjust the coupling degree between the metasurface antenna and the coupling feeding slot.

[0011] Compared with the prior art, the significant advantages of this invention are:

[0012] 1. The antenna of the present invention increases the equivalent capacitance and current length of the metasurface antenna by loading stub capacitance and loading rectangular slots, thereby reducing the resonant frequency of the metasurface antenna and achieving the effect of miniaturization of the metasurface antenna.

[0013] 2. The antenna of the present invention utilizes the advantages of metasurface antennas, such as high gain, wide bandwidth, light weight, low profile, and low cost, and uses them as the radiating element of the antenna to realize a miniaturized metasurface antenna with high gain.

[0014] 3. The antenna of the present invention utilizes the low profile characteristic of metasurface antennas by adding an air layer between the radiating layer and the feeding layer of the metasurface antenna, thereby reducing the manufacturing cost of the antenna.

[0015] 4. The antenna of the present invention adopts a microstrip line slot coupling feeding method, which enables the slot ground plane and the radiating element to couple with each other, thereby further expanding the impedance bandwidth.

[0016] 5. Compared with existing conventional metasurface antennas, this invention maintains the advantages of a wider impedance bandwidth and higher gain of metasurface antennas during antenna miniaturization.

[0017] The present invention will now be described in further detail with reference to the accompanying drawings. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the miniaturized metasurface antenna radiating unit structure in an embodiment.

[0019] Figure 2 This is a schematic diagram of a square unit structure with loaded branches and rectangular grooves in the metasurface structure of the embodiment.

[0020] Figure 3 This is a schematic diagram of the miniaturized metasurface antenna feeding structure for an embodiment.

[0021] Figure 4 Figure (a) shows the current distribution simulation diagram of the miniaturized metasurface antenna in the embodiment, and Figure (b) shows the current distribution simulation diagram of the radiating structure of the miniaturized metasurface antenna.

[0022] Figure 5 This is a schematic diagram of the structure of a miniaturized metasurface antenna as an example.

[0023] Figure 6 The image shows the S-parameter simulation of the miniaturized metasurface antenna in this embodiment.

[0024] Figure 7 This is a simulation diagram of the gain of the miniaturized metasurface antenna in the example.

[0025] Figure 8 The radiation patterns of the miniaturized metasurface antenna in the embodiment are shown in Figure (a), which shows the radiation patterns of the antenna in the E-plane and H-plane at 4.7 GHz, and Figure (b), which shows the radiation patterns of the antenna in the E-plane and H-plane at 5.1 GHz. Detailed Implementation

[0026] To enable those skilled in the art to better understand the present invention, the following description, in conjunction with embodiments and appendices, provides further details. Figure 1-8 The technical solution of the present invention will be further described below.

[0027] This embodiment is a miniaturized metasurface antenna A, which uses a microstrip line slot-coupled feeding structure as the antenna excitation method and a metasurface structure with loaded stubs and rectangular slots as the radiating element, thus realizing a miniaturized high-gain metasurface antenna.

[0028] In this embodiment, the antenna includes three layers: an upper radiating layer h1, a middle air layer h2, and a bottom feed layer h3. A metasurface radiating structure is provided on the radiating layer, and the feed layer is a microstrip line slot-coupled feed structure.

[0029] In this embodiment, the metasurface radiation structure consists of 16 square patches arranged in a 4×4 pattern. A rectangular groove is loaded at the center of each square patch, and branches are loaded at the four corners.

[0030] In the embodiment, a metasurface structure with loaded branches and rectangular grooves, such as... Figure 1 As shown, the antenna radiating layer consists of 16 square patches with loaded stubs and rectangular slots arranged in a 4×4 pattern. The dielectric substrate used for the antenna radiating layer has a dielectric constant of 3.55, a loss tangent of 0.0027, and a thickness of 0.813 mm. Rogers RO 4003. By adjusting the length and width of the stubs and rectangular slots of the metasurface antenna's radiating structure, the equivalent capacitance and equivalent current length of the metasurface antenna are increased, thereby achieving miniaturization of the metasurface antenna.

[0031] In this embodiment, an air layer h2 is introduced between the radiating layer h1 and the feeding layer h3 of the miniaturized metasurface antenna. Since metasurface antennas have the characteristics of low profile, wide bandwidth, and high gain, appropriately reducing the profile height of the radiating layer and replacing it with an air layer can save on antenna manufacturing costs.

[0032] Furthermore, in this embodiment, the feeding structure of the miniaturized metasurface antenna is studied and analyzed. Based on the characteristic mode analysis of the metasurface antenna, the current distribution of the desired antenna mode is obtained, such as... Figure 4 As shown in (a), a suitable feed structure is then designed to excite the antenna based on the current distribution of the desired antenna mode. Since metasurface antennas possess rich characteristic modes, exciting the metasurface antenna by feeding it with a microstrip line slot coupler can couple the metasurface radiating element with the slotted ground plane to generate modes similar to those of the metasurface radiating element, such as... Figure 4 As shown in (b), the impedance bandwidth of the antenna is further extended.

[0033] In summary, there are two main approaches to miniaturizing metasurface antennas: increasing the equivalent capacitance or equivalent inductance, and increasing the equivalent current length. Adding stubs to the radiating structure of a metasurface antenna can effectively increase its equivalent capacitance, while adding rectangular slots can effectively increase its equivalent current length. The stub length has the greatest impact on miniaturization, followed by the length of the rectangular slot, while the stub width and the width of the rectangular slot have the weakest impact. Furthermore, adding an air layer between the radiating layer and the feed layer can reduce the antenna's manufacturing cost to some extent.

[0034] Therefore, in this embodiment, the metasurface radiating structure adjusts the equivalent capacitance of the metasurface antenna by changing the length and width of the loading stubs extending into the square patch; and adjusts the current length of the metasurface antenna by changing the length and width of the rectangular slot. Furthermore, in this embodiment, the loading stubs are inserted at a 45° angle through the right angle of the square patch.

[0035] In the embodiment, the miniaturized metasurface antenna mainly consists of a radiating layer h1, an intermediate air layer h2, and a feed layer h3, such as Figure 1As shown. The first layer of the miniaturized metasurface antenna is a radiating layer h1, which is composed of a Rogers RO4003 dielectric substrate with a thickness of 0.813 mm. The upper surface of the radiating layer is a metasurface radiating element with loaded stubs and rectangular slots, and the lower surface is free of metal. The second layer of the miniaturized metasurface antenna is an air layer h2 with a thickness of 3 mm. Both the upper and lower surfaces of the air layer are free of metal. The bottom layer of the miniaturized metasurface antenna is a feed layer h3, which is composed of a Rogers RO4003 dielectric substrate with a thickness of 0.813 mm. The upper surface of the feed layer is a slotted ground plane a, and the lower surface is a microstrip line b.

[0036] In this embodiment, the microstrip line slot coupling feed structure is a bottom dielectric substrate, the upper surface of the bottom dielectric substrate is a metal ground plane, a coupling feed slot is etched in the middle of the metal ground plane, and the lower surface of the bottom dielectric substrate is a microstrip line. The metasurface antenna is fed by the microstrip line slot coupling feed structure. The coupling degree between the metasurface antenna and the coupling feed slot is adjusted by adjusting the extension length of the loaded stub relative to the coupling feed slot. The length and width of the coupling feed slot are adjustable to adjust the coupling degree between the metasurface antenna and the coupling feed slot.

[0037] In this embodiment, the use of a microstrip line slot-coupled feed structure allows the metasurface radiating element and the slotted ground plane to generate TMs separately. 10 Radiation modes and TM 20 The slot radiation mode achieves the effect of widening the antenna bandwidth. The coupling slot on the upper surface of the feed layer is excited by the microstrip line on the lower surface of the feed layer. The length of the microstrip line extending beyond the coupling slot is s. By adjusting the length of s, as well as the length ls and width ws of the slot, the coupling degree between the metasurface antenna radiating element and the coupling slot can be adjusted.

[0038] Furthermore, in this embodiment, the subarray parameters are optimized and simulated using the electromagnetic simulation software HFSS. The ideal subarray parameters are as follows: side length of the square element with loaded branches and rectangular slots. w 1 = 9 mm, side length of metasurface radiative unit wpatch = 39 mm, unit gap g 1 = 1 mm, Loaded branch width w 2 = 0.3 mm, length of loaded branch l 2 = 5 mm, rectangular groove length lsolt = 8 mm, rectangular groove width wsolt = 0.8 mm, feed gap length ls = 29 mm, feed gap width ws = 0.6 mm, the length of the microstrip line exceeding the feed gap s= 9 mm, microstrip linewidth wf = 1.8 mm, microstrip line length not exceeding the feed gap lf = 25.3 mm.

[0039] Simulation results show that, Figure 6 As shown, antenna | S 11 The simulation results show that the parameters reach a minimum near 4.7 GHz, and the antenna return loss is less than -10 dB within the frequency band of 4.3~5.2 GHz, with an impedance bandwidth of approximately 19.15%. Figure 7 The figure shows the simulated antenna gain versus frequency curve. The miniaturized metasurface antenna achieves an actual gain of 6.92~9.22 dBi within a -10 dB impedance bandwidth. Figure 8 The image shows the simulated radiation pattern characteristics at the two resonant points of 4.7 GHz and 5.1 GHz. Figure 8 As shown in (a), the radiation patterns of the miniaturized metasurface antenna in the E-plane and H-plane at 4.7 GHz are as follows; Figure 8 (b) shows the radiation patterns of the miniaturized metasurface antenna in the E-plane and H-plane at 5.1 GHz.

[0040] In summary, the miniaturized metasurface antenna designed in this invention has advantages such as simple structure, wide bandwidth, high gain, and low cost. Compared with other types of metasurface antennas, the metasurface antenna involved in this invention has broad application prospects in the C-band.

[0041] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the claimed invention.

Claims

1. A miniaturized metasurface antenna, characterized in that, The antenna comprises three layers: an upper radiating layer, a middle air layer, and a bottom feed layer. A metasurface radiating structure is disposed on the radiating layer, and the feed layer is a microstrip line slot-coupled feed structure. The metasurface radiating structure consists of 16 square patches arranged in a 4×4 pattern. A rectangular slot is loaded at the center of each square patch, and stubs are loaded at the four corners. The equivalent capacitance of the metasurface antenna is adjusted by changing the length and width of the loaded stubs extending into the square patches; the current length of the metasurface antenna is adjusted by changing the length and width of the rectangular slots. The subarray parameters of the antenna are as follows: the side length of the square element with loaded stubs and rectangular slots is w1 = 9 mm, the side length of the metasurface radiating element is wpatch = 39 mm, the element gap is g1 = 1 mm, the width of the loaded stub is w2 = 0.3 mm, the length of the loaded stub is l2 = 5 mm, the length of the rectangular slot is lsolt = 8 mm, the width of the rectangular slot is wsolt = 0.8 mm, the length of the feed slot is ls = 29 mm, the width of the feed slot is ws = 0.6 mm, the length of the microstrip line extending beyond the feed slot is s = 9 mm, the width of the microstrip line is wf = 1.8 mm, and the length of the microstrip line not extending beyond the feed slot is lf = 25.3 mm.

2. The miniaturized metasurface antenna according to claim 1, characterized in that, The loaded branch is inserted at a right angle via a square patch.

3. The miniaturized metasurface antenna according to claim 2, characterized in that, The angle at which the loaded branch is inserted is 45°.

4. The miniaturized metasurface antenna according to claim 3, characterized in that, The microstrip line slot coupling feed structure is a bottom dielectric substrate, the upper surface of the bottom dielectric substrate is a metal ground plane, a coupling feed slot is etched in the middle of the metal ground plane, and the lower surface of the bottom dielectric substrate is a microstrip line. The metasurface antenna is fed by the microstrip line slot coupling feed structure. The degree of coupling between the metasurface antenna and the coupling feed slot is adjusted by adjusting the extension length of the loaded stub relative to the coupling feed slot; the length and width of the coupling feed slot are adjustable to adjust the degree of coupling between the metasurface antenna and the coupling feed slot.

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