An irregular subarray-based metasurface array structure

Abstract

The application provides a metasurface array, which is composed of several metasurface subarrays of different shapes; the metasurface subarrays cannot coincide with the original metasurface subarrays after being rotated by 90°, or 180°, or 270°, or being mirror flipped, the application adopts irregular subarray division for a super large scale reflector array, compared with a traditional structure without subarrays, the number of bias lines is greatly reduced, that is, the number of control interfaces of the smart reflector is reduced, under the condition that the performance indicators such as scattering pattern gain and sidelobe are slightly reduced; compared with regular subarray division, the grating lobe level can be obviously suppressed due to breaking the periodicity of the phase center of the subarray, and the application can effectively reduce the system cost, power consumption and engineering implementation difficulty.

Description

Technical Field

[0001] This invention relates to the field of wireless communication technology, and in particular to a metasurface array structure based on irregular subarrays. Background Technology

[0002] Smart reflectors can be used to fill gaps in weak coverage areas, similar to repeaters, serving as an intermediate node between base stations and end users. However, smart reflectors are generally composed of passive components, do not contain radio frequency links, and cannot amplify and forward received signals. To significantly improve the performance of wireless communication links, it is necessary to increase the number of units in a single smart reflector and improve the array gain, potentially requiring an array size in the thousands of yuan range.

[0003] However, due to limitations in system cost, engineering implementation difficulty, and device capabilities, independent control of each unit in an ultra-large-scale intelligent reflector is impractical. Subarray technology offers a compromise and effective solution, minimizing system cost and engineering complexity while maintaining array performance. The increasing scale of arrays has spurred the development and application of subarray technology. Simple subarray partitioning schemes (such as regular adjacency like a checkerboard pattern) can lead to reduced array gain and the appearance of grating lobes, severely impacting the performance of the scattering pattern. Therefore, research on optimal subarray partitioning and processing is urgently needed.

[0004] CN 115133291 A discloses an irregular antenna subarray. The central part of the array consists of a 2*2 regular antenna subarray, where antenna elements are combined in 2*2 equal-path (equal-phase) configurations and connected to one RF channel. The peripheral part consists of a 3*3 irregular antenna subarray. In this subarray, four antenna elements (out of 122 possible combinations) are selected and combined in equal-path (equal-phase) configurations and connected to one RF channel. The other five elements not selected are not connected to any other RF channels. However, in this irregular subarray structure, some elements do not participate in radiation, resulting in gain loss in the array's radiation pattern. Summary of the Invention

[0005] This application provides a metasurface array structure with irregular subarrays, in which all elements participate in the modulation of the incident wave, and the scattering pattern has no gain loss, no empty positions, and no invalid reflection elements.

[0006] To achieve the above-mentioned technical objectives, the technical solution adopted in this application is as follows:

[0007] This application provides a metasurface array, which consists of at least two metasurface subarrays of different shapes;

[0008] The metasurface subarray consists of n metasurface units, where n is an integer greater than 2. These metasurface units can be arranged in different ways to form metasurface subarrays of different shapes.

[0009] The metasurface subarray cannot overlap with the original metasurface subarray after being rotated by 90°, 180°, or 270°, or after being mirrored and flipped.

[0010] The metasurface unit is provided with an X-polarization control unit and a Y-polarization control unit, which can realize independent control of dual polarization. The X-polarization control unit is controlled by the X-polarization voltage bias line, and the Y-polarization control unit is controlled by the Y-polarization voltage bias line.

[0011] In the aforementioned metasurface subarray, the X-polarization voltage bias lines in the n metasurface units are connected and share a first electrical outlet, which can control the voltage of all X-polarization control units in the metasurface subarray.

[0012] In the aforementioned metasurface subarray, the Y-polarization voltage bias lines of the n metasurface units are connected and share a second electrical outlet, which can control the voltage of all Y-polarization control units in the metasurface subarray.

[0013] As a preferred embodiment, the X-polarization control unit and the Y-polarization control unit are either PIN diodes or varactor diodes, and the X-polarization control unit and the Y-polarization control unit are of the same type.

[0014] As a preferred embodiment, the metasurface array consists of two metasurface subarrays of different shapes.

[0015] Preferably, the metasurface array consists of T-shaped subarrays and L-shaped subarrays.

[0016] The T-shaped subarray and the L-shaped subarray are 4-element subarrays, which are composed of 4 metasurface units forming a T-shape or an L-shape.

[0017] As a preferred embodiment, the metasurface is composed of several metasurface subarrays of different shapes, including one or more of quaternary, pentagonal, hexaternary, heptagonal, and octagonal subarrays.

[0018] In a preferred embodiment, the metasurface unit further includes, from top to bottom along the direction of the incident electromagnetic wave, a metal pattern layer, a first dielectric substrate, a metal ground, a second dielectric substrate, a Y-polarized voltage bias line layer, a third dielectric substrate, and an X-polarized voltage bias line layer.

[0019] The metal pattern layer includes a patch, and the X-polarization control unit and the Y-polarization control unit are disposed on the patch;

[0020] The first dielectric substrate has a through-hole, and the patch and the metal ground are equipotentially connected.

[0021] The X-polarization voltage bias line is integrated on the X-polarization voltage bias line layer;

[0022] The Y-polarized voltage bias line is integrated on the Y-polarized voltage bias line layer.

[0023] Preferably, the metal pattern layer further includes a first pad and a second pad; the X-polarization control unit is fixed between the patch and the first pad; the Y-polarization control unit is fixed between the patch and the second pad. The introduction of pads allows for better control of the X-polarization control unit and the Y-polarization control unit.

[0024] Preferably, a through-hole is provided on the first dielectric substrate, the second dielectric substrate, and the third dielectric substrate, and the second pad is equipotentially connected to the X-polarized voltage bias line layer through the second metallized through-hole.

[0025] Preferably, a through-hole is provided on the first dielectric substrate and the second dielectric substrate, and the first pad is equipotentially connected to the Y-polarized voltage bias line layer through the third metallized through-hole.

[0026] As a preferred embodiment, the patch includes one or more of the following shapes: circular, square, hexagonal, and octagonal.

[0027] Advantages of this application:

[0028] This technical solution targets ultra-large-scale reflective arrays and adopts irregular subarray division. Compared with the traditional subarray-less structure, it greatly reduces the number of bias lines, i.e., the number of control interfaces of the intelligent reflective surface, while slightly reducing the performance indicators such as scattering pattern gain and sidelobes. Compared with regular subarray division, it can significantly suppress grating lobe level by breaking the periodicity of the subarray phase center. This technical solution can effectively reduce system cost, power consumption and engineering implementation difficulty. Attached Figure Description

[0029] Figure 1 This is a schematic diagram of the connection of the X-polarization voltage bias line of a T-shaped irregular subarray provided in one embodiment of this application;

[0030] Figure 2 This is a schematic diagram of the connection of the Y-polarized voltage bias line of a T-shaped irregular subarray provided in one embodiment of this application;

[0031] Figure 3 This is a schematic diagram showing the connection of the X-polarization voltage bias line of an L-shaped irregular subarray provided in one embodiment of this application.

[0032] Figure 4 This is a schematic diagram showing the connection of the Y-polarized voltage bias line of an L-shaped irregular subarray provided in one embodiment of this application.

[0033] Figure 5 This is a schematic diagram of the front structure of a 16*16 metasurface array provided in one embodiment of this application;

[0034] Figure 6 This is a schematic diagram of the X-polarized voltage bias line layer structure of a 16*16 metasurface array provided in one embodiment of this application;

[0035] Figure 7 This is a schematic diagram of the Y-polarized voltage bias line layer structure of a 16*16 metasurface array provided in one embodiment of this application;

[0036] Figure 8 This is a schematic diagram of the structure of a metasurface unit provided in one embodiment of this application;

[0037] Figure 9 This is a schematic diagram of the structure of a metasurface unit provided in one embodiment of this application;

[0038] Figure 10 This is a schematic diagram of the structure of a metasurface unit provided in one embodiment of this application;

[0039] Figure 11 This is a schematic diagram of the X-polarized voltage bias line layer structure of a 16*16 metasurface array provided in a comparative example of this application.

[0040] Figure 12 This is a schematic diagram of the X-polarized voltage bias line layer structure of a 16*16 metasurface array provided in a comparative example of this application.

[0041] Figure 13 The varactor diode provided in one embodiment of this application is loaded with the reflection phase under different voltages;

[0042] Figure 14 This is a scattering pattern of an incident wave perpendicularly irradiating a metasurface array in one embodiment of this application.

[0043] In the figure: 101-Metal pattern layer; 201-First dielectric substrate; 301-Metal ground; 401-Second dielectric substrate; 501-Y-polarization voltage bias line layer; 601-Third dielectric substrate; 701-X-polarization voltage bias line layer; 111-Pad; 121-Y-polarization control unit; 122-X-polarization control unit; 131-First pad; 132-Second pad; 511-Y-polarization voltage bias line; 711-X-polarization voltage bias line; 211-First metallized via; 811-Third metallized via; 821-Second metallized via. Detailed Implementation

[0044] The features and exemplary embodiments of various aspects of this application will be described in detail below. To make the objectives, technical solutions, and advantages of this application clearer, the application will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are only intended to explain this application and not to limit it. For those skilled in the art, this application can be implemented without some of these specific details. The following description of the embodiments is merely to provide a better understanding of this application by illustrating examples.

[0045] In one embodiment of this application, a metasurface array is provided, which consists of at least two metasurface subarrays of different shapes;

[0046] The metasurface subarray consists of n metasurface units, where n is an integer greater than 2. These metasurface units can be arranged in different ways to form metasurface subarrays of different shapes.

[0047] The metasurface subarray cannot overlap with the original metasurface subarray after being rotated by 90°, 180°, or 270°, or after being mirrored and flipped.

[0048] The metasurface unit includes a Y-polarization control unit 121 and an X-polarization control unit 122, which can realize independent control of dual polarization. The X-polarization control unit 122 is controlled by the X-polarization voltage bias line 711, and the Y-polarization control unit 121 is controlled by the Y-polarization voltage bias line 511.

[0049] In the aforementioned metasurface subarray, the X-polarization voltage bias lines 711 in the n metasurface units are connected and share a first electrical outlet, which can control the voltage of all X-polarization control units 121 in the metasurface subarray.

[0050] In the aforementioned metasurface subarray, the Y-polarization voltage bias lines 511 in the n metasurface units are connected and share a second electrical outlet, which can control the voltage of all X-polarization control units 122 in the metasurface subarray.

[0051] The metasurface subarrays can be assembled into a metasurface array.

[0052] Compared with existing technologies, the main design feature of this application is that it divides the metasurface array into at least two metasurface subarrays of different shapes, and aggregates the X-polarization voltage bias lines 711 and Y-polarization voltage bias lines 511 of the metasurface units in each subarray. A single circuit or control interface can control the bias voltages of all Y-polarization control units 121 and X-polarization control units 122 in a given metasurface subarray, effectively reducing the number of control interfaces in the metasurface array. For example, a metasurface array composed of 16*16 dual-polarization metasurface units would require 512 control interfaces if subarray control is not used; however, with the scheme of this application, dividing the array into 4-element metasurface subarrays of different shapes, only 128 control interfaces are needed to control the metasurface array.

[0053] While existing technologies divide metasurfaces into subarrays, they typically employ regular subarrays, such as traditional 2x2 or 3x3 checkerboard subarrays. These subarrays, after being rotated or mirrored by 90° / 180° / 270°, completely overlap with the original subarray. However, such regular subarrays exhibit grating lobes and significant gain loss in practical applications. Irregular subarrays effectively overcome this problem. The irregular subarray division disrupts the periodicity of the phase center distribution within the subarray, thus eliminating grating lobes in the array factor. The gain loss is only slightly lower than that of a subarray-less structure, achieving a better technical effect. Furthermore, in the irregular subarray structure provided in this solution, all elements participate in the modulation of the incident wave, resulting in no gain loss in the scattering pattern.

[0054] As a preferred embodiment, the Y-polarization control unit 121 and the X-polarization control unit 122 are either PIN diodes or varactor diodes, and the Y-polarization control unit 121 and the X-polarization control unit 122 are of the same type. PIN diodes or varactor diodes have varied parameters and are technologically mature, allowing for specific selection based on actual application requirements.

[0055] In one embodiment of this application, the metasurface array consists of two metasurface subarrays of different shapes.

[0056] As a preferred method, such as Figures 1-4 As shown, the metasurface array consists of T-shaped subarrays and L-shaped subarrays.

[0057] The T-shaped subarray and the L-shaped subarray are 4-element subarrays, which are composed of 4 metasurface units forming a T-shape or an L-shape.

[0058] In the technical solution of this application, depending on the arrangement of the metasurface units, the metasurface subarray can usually be in various forms. Here, the subarray and its rotated and mirrored forms are regarded as the same seed array. Figures 1-4The diagram provides the configuration of a T-shaped or mirrored L-shaped metasurface subarray composed of four metasurface units. As can be seen from the diagram, in the T-shaped subarray and the mirrored L-shaped subarray, the X-polarized voltage bias line 711 and the Y-polarized voltage bias line 511 are connected together according to the shape of the subarray. Only one electrical outlet is needed to control all the bias lines in the subarray.

[0059] Using the aforementioned metasurface units as basic building blocks, Figure 1 , Figure 2 A T-shaped irregular subarray consisting of four elements is given. The X-polarization voltage bias lines 711 of the four elements are connected together, meaning that the supply voltage of the four elements is always the same. Similarly, the Y-polarization voltage bias lines 511 of the four elements are also connected together. Subarrays obtained by rotating the T-shaped subarray by 90°, 180°, and 270° belong to the same subarray category. The same applies to other shapes; subarrays obtained by rotation and / or mirroring belong to the same category.

[0060] Figure 3 , Figure 4 A mirror-image L-shaped irregular subarray consisting of four elements is presented. The X-polarization voltage bias lines 711 of the four elements are connected together, and the Y-polarization voltage bias lines 511 of the four elements are connected together. Subarrays obtained by rotating the mirror-image L-shaped subarray by 90°, 180°, and 270° belong to the same subarray category.

[0061] Through calculation, a large 16*16 array can be achieved by rationally arranging T-shaped subarrays and mirrored L-shaped subarrays. Each unit in this array is an effective reflection unit, and there are no gaps in certain positions in the array due to the irregular shape of the subarrays. The array area utilization rate is consistent with that without subarrays.

[0062] Figure 5 , Figure 6 , Figure 7 A schematic diagram of the front side, X-polarization voltage bias line 711 layer 701 and Y-polarization voltage bias line 511 layer 501 of a 16*16 metasurface array consisting of several T-shaped subarrays and mirrored L-shaped subarrays is provided. It can be seen that only 128 interfaces are needed to control the entire metasurface array for dual-polarization operation.

[0063] It should be noted that there is more than one way to assemble a 16x16 array using irregular subarrays, and 16x16 arrays are not the only possible configurations. The type of subarray, its size (quadruple, hexaple, etc.), and its arrangement determine the ratio between the metasurface units and the voltage bias lines (corresponding to the control interfaces). These ratios need to be selected based on factors such as scattering pattern gain, sidelobes, and the number of control interfaces. Through calculation, irregular metasurface subarrays of various shapes can be designed to form metasurface arrays of different sizes.

[0064] In one embodiment of this application, the metasurface is composed of several metasurface subarrays of different shapes, including one or more of quaternary subarrays, pentagonal subarrays, hexaternary subarrays, heptagonal subarrays, and octagonal subarrays.

[0065] In one embodiment of this application, such as Figure 8 As shown, the metasurface unit further includes, from top to bottom along the direction of the incident electromagnetic wave, a metal pattern layer 101, a first dielectric substrate 201, a metal ground 301, a second dielectric substrate 401, a Y-polarized voltage bias line layer 501, a third dielectric substrate 601, and an X-polarized voltage bias line layer 701.

[0066] The metal pattern layer 101 includes a patch 111, and the X-polarization control unit 121 and the X-polarization control unit 122 are disposed on the patch 111;

[0067] The first dielectric substrate 201 is provided with a through-hole 211, and the patch 111 and the metal ground 301 are connected at the same potential through the first metallized through-hole 211.

[0068] The X-polarization voltage bias line 711 is integrated on the X-polarization voltage bias line layer 701;

[0069] The Y-polarized voltage bias line 511 is integrated on the Y-polarized voltage bias line layer 501.

[0070] As a preferred embodiment, the metal pattern layer 101 is further provided with a first pad 131 and a second pad 132; the Y-polarization control unit 121 is fixed between the patch 111 and the first pad 131; the X-polarization control unit 122 is fixed between the patch 111 and the second pad 132. The introduction of pads can better fix the Y-polarization control unit 121 and the X-polarization control unit 122.

[0071] In one embodiment of this application, such as Figure 9 ,like Figure 10 As shown, the first dielectric substrate 201, the second dielectric substrate 401, and the third dielectric substrate 601 are provided with through second metallized vias 821, and the second pad 132 is connected to the X-polarization voltage bias line layer 701 at the same potential through the second metallized via 821.

[0072] In one embodiment of this application, a through third metallized via 811 is provided on the first dielectric substrate 201 and the second dielectric substrate 401, and the first pad 131 is connected to the Y-polarized voltage bias line 511 layer 501 at the same potential through the third metallized via 811.

[0073] In one embodiment of this application, the patch 111 includes one or more of the following shapes: circular, square, hexagonal, and octagonal, which can be selected according to different application scenarios.

[0074] like Figures 5-7 As shown, one embodiment of this application provides a 16*16 array composed of irregular subarrays, and another embodiment provides... Figure 11 The 16x16 array without subarrays shown, and as shown in the figure Figure 12 The 16*16 array formed by the 4-element 2*2 regular subarrays shown is used as a comparative example.

[0075] Taking a varactor diode selected on a metasurface unit as an example, when a plane electromagnetic wave irradiates the metasurface array, the metasurface unit can adjust the phase of the scattered (or reflected) electromagnetic wave by applying different voltages to the X-polarized voltage bias line 711.

[0076] from Figure 13 As can be seen, taking the 3.7GHz frequency point as an example, when a plane wave is perpendicularly irradiated onto the metasurface unit, and the voltage changes from 0V to 20V, the phase of the scattered (or reflected) electromagnetic wave changes from 125° to -162°.

[0077] When an incident wave illuminates a 16*16 metasurface array, the reflection phase of the electromagnetic wave in each subarray is individually controlled. The different reflection phases of the reflected waves can be scanned or transformed.

[0078] Figure 14 The scattering patterns of a 16*16 metasurface array with incident waves perpendicularly illuminating it are presented, under different subarray structures: no subarray, 2*2 regular subarray, T-shaped subarray, and mirrored L-shaped irregular subarray. Taking X-polarization as an example, in the no-subarray structure, the element spacing is approximately 0.5λ, and the voltage / reflection phase of the 256 metasurface elements is independently controlled. The scattering pattern gain is 23dBi, and the highest sidelobe is -20dB. In the 2*2 regular subarray, the subarray phase-tuning spacing is 1λ. The scattering pattern shows very obvious grating lobes around 10°, and the gain decreases significantly (see Table 1 for details). The irregular subarray division disrupts the periodicity of the phase center distribution of the subarrays in the array, thereby eliminating grating lobes in the array factor. The gain decreases only slightly compared to the no-subarray structure, achieving good technical results with a significant reduction in the control interface.

[0079] Table 1 Comparison of indicators under different array configurations (taking X-polarization as an example)

[0080] Array type Number of units Number of control interfaces Gain Side petals No Child Formation 256 256 23dBi@60° -20dB 2x2 regular subarray 256 64 10dBi@60° Higher grating lobe Irregular subarray 256 64 20.5dBi@60° -20dB

Claims

1. A metasurface array, characterized in that, It consists of at least two metasurface subarrays of different shapes; The metasurface subarray consists of n metasurface units, where n is an integer greater than 2. These metasurface units can be arranged in different ways to form metasurface subarrays of different shapes. The metasurface subarray cannot overlap with the original metasurface subarray after being rotated by 90°, 180°, or 270°, or after being mirrored and flipped. The metasurface unit is provided with an X-polarization control unit and a Y-polarization control unit, which can realize independent control of dual polarization. The X-polarization control unit is controlled by the X-polarization voltage bias line, and the Y-polarization control unit is controlled by the Y-polarization voltage bias line. In the aforementioned metasurface subarray, the X-polarization voltage bias lines in the n metasurface units are connected and share a first electrical outlet, which can control the voltage of all X-polarization control units in the metasurface subarray. In the aforementioned metasurface subarray, the Y-polarization voltage bias lines of the n metasurface units are connected and share a second electrical outlet, which can control the voltage of all Y-polarization control units in the metasurface subarray.

2. The metasurface array according to claim 1, characterized in that: The X-polarization control unit and the Y-polarization control unit are of the same type, namely a PIN diode or a varactor diode.

3. The metasurface array according to claim 1, characterized in that: The metasurface array consists of two metasurface subarrays of different shapes.

4. The metasurface array according to claim 3, characterized in that: The metasurface array consists of T-shaped subarrays and L-shaped subarrays. The T-shaped subarrays and the L-shaped subarrays are 4-element subarrays, which are composed of 4 metasurface units forming a T-shape or an L-shape.

5. The metasurface array according to claim 1, characterized in that: The metasurface subarray includes one or more of the following: quaternary subarray, pentagonal subarray, hexaternary subarray, heptagonal subarray, and octagonal subarray.

6. The metasurface array according to any one of claims 1 to 5, characterized in that: The metasurface unit further includes, from top to bottom along the direction of the incident electromagnetic wave, a metal pattern layer, a first dielectric substrate, a metal ground, a second dielectric substrate, a Y-polarized voltage bias line layer, a third dielectric substrate, and an X-polarized voltage bias line layer. The metal pattern layer includes a patch, and the X-polarization control unit and the Y-polarization control unit are disposed on the patch; The first dielectric substrate has a through-hole, and the patch and the ground plane are equipotentially connected through the first metallized via. The X-polarization voltage bias line is integrated on the X-polarization voltage bias line layer; The Y-polarized voltage bias line is integrated on the Y-polarized voltage bias line layer.

7. The metasurface array according to claim 6, characterized in that: The metal pattern layer is further provided with a first pad and a second pad; the X polarization control unit is fixed between the patch and the first pad; the Y polarization control unit is fixed between the patch and the second pad.

8. The metasurface array according to claim 7, characterized in that: The first dielectric substrate, the second dielectric substrate, and the third dielectric substrate are provided with through-holes, and the second pad is connected to the X-polarization voltage bias line layer at the same potential through the through-holes.

9. The metasurface array according to claim 7, characterized in that: A through-hole is provided on the first dielectric substrate and the second dielectric substrate, and the first pad is connected to the Y-polarized voltage bias line layer at the same potential through the third metallized through-hole.

10. The metasurface array according to claim 6, characterized in that: The shape of the patch includes one or more of the following: circular, square, hexagonal, and octagonal.

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