Metamaterial structure and radome

Abstract

The application discloses a metamaterial structure and a radome. The metamaterial structure comprises a substrate and a conductive geometric structure arranged on the surface of the substrate. The conductive geometric structure comprises a plurality of conductive geometric units. Each conductive geometric unit comprises a patch. The patch comprises protruding structures protruding in multiple directions. The protruding structures can be obtained by stretching and / or compressing an initial patch shape. The protruding amplitude of the protruding structures in a first direction is greater than the protruding amplitude of the protruding structures in other directions. The multiple directions include the first direction and the other directions. The patch is used for independently modulating electromagnetic response in the first direction.

Description

Technical Field

[0001] This invention relates to the field of electromagnetic communication, and more specifically, to a metamaterial structure and radome. Background Technology

[0002] Radomes are typically composed of metamaterial microstructures. Conventional metamaterial microstructures can relatively freely modulate transmission and reflection under a single polarization. However, under wide frequency bands and medium to high incident angles, once the optimized design of transmission and reflection under a single polarization (e.g., TE) is completed, it is usually extremely difficult to independently optimize the transmission and reflection of another polarization (e.g., TM). In other words, after achieving a balance between high and low frequencies in the transmission and reflection of two orthogonal polarizations, it is difficult to independently optimize the transmission and reflection of one of the polarizations.

[0003] Existing technologies typically reduce the polarization amplitude and phase difference between TE and TM at medium and large incident angles through the following methods:

[0004] 1) Variable thickness stack design optimizes the thickness of the stack based on different polarization ratios. However, the fabrication of variable thickness dielectric layers significantly increases the processing requirements and costs.

[0005] 2) Zonal design: Based on the polarization ratio weight, different polarization regions are divided to carry out the optimal microstructure design.

[0006] 3) Gradual design: Based on the polarization ratio weight, design the corresponding optimal size gradient microstructure.

[0007] The design schemes of layered variable thickness, metamaterial microstructure partitioning or gradient design are all based on the polarization distribution of the irradiation area and are customized to design the metamaterial microstructure. They are only applicable to cases where the polarization angle of the incident wave irradiation area is regularly distributed. They fail to overcome the bottleneck of mutual constraint between the TE and TM polarization of a single metamaterial microstructure. They cannot meet the needs of cases where the polarization distribution in the incident wave irradiation area is irregular or cannot be partitioned, or the polarization distribution changes with the polarization direction of the incident wave, such as circular polarization, elliptical polarization or linear polarization, and rotation of the incident wave polarization direction. Summary of the Invention

[0008] This invention provides a metamaterial structure and radome to at least solve the problem in related technologies that the electromagnetic response in different polarization directions cannot be independently modulated.

[0009] According to an embodiment of the present invention, a metamaterial structure is provided, comprising: a substrate; a conductive geometry disposed on the surface of the substrate; wherein the conductive geometry comprises a plurality of conductive geometric units, each of the conductive geometric units comprising a patch, the patch comprising protruding structures protruding in a plurality of directions, and the protrusion amplitude of the protruding structures in a first direction being greater than the protrusion amplitude in other directions, the plurality of directions including the first direction and the other directions, the patch being used to independently modulate the electromagnetic response in the first direction.

[0010] In one exemplary embodiment, each conductive geometric unit also includes a connecting loop, with the patch inside the connecting loop and not connected to it.

[0011] In one exemplary embodiment, the connecting loop is composed of a plurality of first bent structures, or the connecting loop is composed of a plurality of straight structures.

[0012] In one exemplary embodiment, the protruding structure includes: an elliptical first protrusion, wherein the first direction is the direction of the major axis of the first protrusion.

[0013] In an exemplary embodiment, the second protrusion is polygonal, wherein the first direction includes the target protrusion direction of the second protrusion, the length of the first target edge point in the target protrusion direction from the center point of the second protrusion is greater than the length of the second target edge point in other directions from the center point, the first target edge point is the point farthest from the center point in the target protrusion direction, and the second target edge point is the point farthest from the center point in other directions.

[0014] In one exemplary embodiment, the second protrusion includes: a plurality of conductive structures, wherein each of the conductive structures forms one side of the polygon; a first conductive patch; wherein each of the conductive structures is connected to the first conductive patch.

[0015] In one exemplary embodiment, each of the conductive structures described above includes a plurality of second bending structures, wherein the plurality of second bending structures are connected to the first conductive patch.

[0016] In an exemplary embodiment, the electromagnetic response in the first direction is modulated by adjusting the parameters of the protruding structure, wherein the parameters of the protruding structure include at least one of the following: shape, size, position, material, and protrusion direction.

[0017] In one exemplary embodiment, the electromagnetic response in the first direction is modulated by adjusting the number of the plurality of conductive geometric units and / or by adjusting the arrangement of the plurality of conductive geometric units.

[0018] In one exemplary embodiment, the patch is obtained by stretching and / or compressing a patch of initial shape.

[0019] According to yet another embodiment of the present invention, an antenna radome is also provided, comprising: any of the metamaterial structures described above.

[0020] According to this invention, a metamaterial structure includes a substrate; a conductive geometric structure disposed on the surface of the substrate; wherein the conductive geometric structure includes multiple conductive geometric units, each of which includes a patch, the patch including protruding structures in multiple directions, wherein the protrusion amplitude in a first direction is greater than the protrusion amplitude in other directions, the multiple directions including the first direction and other directions, and the patch is used to independently modulate the electromagnetic response in the first direction. By adjusting the metamaterial microstructure in a polarization direction, the electromagnetic properties in that polarization direction can be optimized, ultimately achieving the goal of independently modulating the electromagnetic response in different polarization directions. Therefore, the problem of not being able to independently modulate the electromagnetic response in different polarization directions in related technologies can be solved. Attached Figure Description

[0021] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with the invention and, together with the description, serve to explain the principles of the invention.

[0022] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, for those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0023] Figure 1 This is a schematic diagram (a) of a metamaterial structure according to an embodiment of the present invention;

[0024] Figure 2 This is a schematic diagram of TE and TM polarized incident waves in metamaterial microstructures (I);

[0025] Figure 3 This is a schematic diagram of TE and TM polarized incident waves of metamaterial microstructures (II);

[0026] Figure 4 This is a schematic diagram (II) of a metamaterial structure according to an embodiment of the present invention;

[0027] Figure 5 This is a diagram of the microstructure arrangement of a six-fold rotationally symmetric metamaterial (I);

[0028] Figure 6 This is a microstructure outline diagram of a six-fold rotationally symmetric metamaterial (Part 1);

[0029] Figure 7 This is a simulation diagram of IPD_TE with second-order rotational symmetry;

[0030] Figure 8 This is a simulation diagram of IPD_TE six-fold rotational symmetry;

[0031] Figure 9 This is a simulation diagram of IPD_TM with second-order rotational symmetry;

[0032] Figure 10 This is a simulation diagram of IPD_TM six-fold rotational symmetry;

[0033] Figure 11 This is a simulation diagram of IPD_MIX with second-order rotational symmetry;

[0034] Figure 12 This is a simulation diagram of IPD_MIX six-fold rotational symmetry;

[0035] Figure 13 This is a simulation diagram of S11_TE with second-order rotational symmetry;

[0036] Figure 14 This is a simulation diagram of S11_TE six-fold rotational symmetry;

[0037] Figure 15 This is a simulation diagram of S11_TM with second-order rotational symmetry;

[0038] Figure 16 This is a simulation diagram of the S11_TM six-fold rotational symmetry.

[0039] Figure 17 This is a simulation diagram of IPD_TE with second-order rotational symmetry;

[0040] Figure 18 This is a simulation diagram of IPD_TE six-fold rotational symmetry;

[0041] Figure 19 This is a simulation diagram of IPD_TM with second-order rotational symmetry;

[0042] Figure 20 This is a simulation diagram of IPD_TM six-fold rotational symmetry;

[0043] Figure 21 This is a simulation diagram of IPD_MIX with second-order rotational symmetry;

[0044] Figure 22 This is a simulation diagram of IPD_MIX six-fold rotational symmetry;

[0045] Figure 23 This is a simulation diagram of S11_TE with second-order rotational symmetry;

[0046] Figure 24This is a simulation diagram of S11_TE six-fold rotational symmetry;

[0047] Figure 25 This is a simulation diagram of S11_TM with second-order rotational symmetry;

[0048] Figure 26 This is a simulation diagram of the S11_TM six-fold rotational symmetry.

[0049] Figure 27 This is a diagram of the microstructure arrangement of a six-fold rotationally symmetric metamaterial (II).

[0050] Figure 28 This is the outline diagram of the microstructure of a six-fold rotationally symmetric metamaterial (II);

[0051] Figure 29 This is a simulation diagram of IPD_TE with second-order rotational symmetry;

[0052] Figure 30 This is a simulation diagram of IPD_TE six-fold rotational symmetry;

[0053] Figure 31 This is a simulation diagram of IPD_TM with second-order rotational symmetry;

[0054] Figure 32 This is a simulation diagram of IPD_TM six-fold rotational symmetry;

[0055] Figure 33 This is a simulation diagram of IPD_MIX with second-order rotational symmetry;

[0056] Figure 34 This is a simulation diagram of IPD_MIX six-fold rotational symmetry;

[0057] Figure 35 This is a simulation diagram of S11_TE with second-order rotational symmetry;

[0058] Figure 36 This is a simulation diagram of S11_TE six-fold rotational symmetry;

[0059] Figure 37 This is a simulation diagram of S11_TM with second-order rotational symmetry;

[0060] Figure 38 This is a simulation diagram of the S11_TM six-fold rotational symmetry.

[0061] Figure 39 This is a simulation diagram of IPD_TE with second-order rotational symmetry;

[0062] Figure 40 This is a simulation diagram of IPD_TE six-fold rotational symmetry;

[0063] Figure 41 This is a simulation diagram of IPD_TM with second-order rotational symmetry;

[0064] Figure 42 This is a simulation diagram of IPD_TM six-fold rotational symmetry;

[0065] Figure 43 This is a simulation diagram of IPD_MIX with second-order rotational symmetry;

[0066] Figure 44 This is a simulation diagram of IPD_MIX six-fold rotational symmetry;

[0067] Figure 45 This is a simulation diagram of S11_TE with second-order rotational symmetry;

[0068] Figure 46 This is a simulation diagram of S11_TE six-fold rotational symmetry;

[0069] Figure 47 This is a simulation diagram of S11_TM with second-order rotational symmetry;

[0070] Figure 48 This is a simulation diagram of the S11_TM six-fold rotational symmetry.

[0071] Explanation of reference numerals in the attached figures:

[0072] 1. Substrate; 2. Conductive geometry; 21. Conductive geometric unit; 3. Second protrusion. Detailed Implementation

[0073] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0074] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of the invention described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover a non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0075] This embodiment provides a metamaterial structure. Figure 1This is a schematic diagram of a metamaterial structure according to an embodiment of the present invention, such as... Figure 1 The diagram shown is a planar view of the metamaterial structure along the X and Y coordinate directions, where Q represents the intersection deviation value in the X and Y directions. The metamaterial structure includes:

[0076] substrate1;

[0077] Conductive geometry 2 is disposed on the surface of substrate 1;

[0078] The conductive geometric structure 2 includes multiple conductive geometric units 21, each of which includes a patch. The patch includes protruding structures that protrude in multiple directions, and the protrusion amplitude of the protrusion structure in the first direction is greater than the protrusion amplitude in other directions. The multiple directions include the first direction and other directions. The patch is used to independently modulate the electromagnetic response in the first direction.

[0079] Optionally, the multiple directions in this embodiment include the polarization directions of the electromagnetic wave at different incident angles. For example, in scenarios where the electromagnetic responses (e.g., S21, S11, etc.) of the two polarization directions (TE, TM) influence each other at medium and high incident angles. The definitions of TE and TM polarization are as follows: Figure 2 and Figure 3 As shown.

[0080] like Figure 2 As shown, the metamaterial microstructure is flanked by vacuum, with its dielectric constant and permeability denoted as ε0 and μ0, respectively. The interface between the two is the XOY plane, with the interface normal n along the +Z axis. An incident plane wave E... i Along k i Directional propagation, the angle between which it and the interface normal n is the angle of incidence (denoted as θ). i Incident plane wave E i Along the propagation direction k i The plane containing the normal n of the interface is called the incident plane. For the incident plane wave E i The electric field component parallel to the incident plane is called the parallel polarized TM wave (denoted as E). i / / The electric field component perpendicular to the incident plane is called the vertically polarized TE wave (denoted as E). i ⊥ The angle between the direction of the incident wave electric field and the incident surface is the polarization angle (denoted as β).

[0081] like Figure 3As shown, extending further to the XOY plane where the metamaterial microstructure is located, the vertically polarized TE wave is parallel to the YOZ plane, while the parallel-polarized TM wave is parallel to the XOZ plane. The technical solution of this invention combines the directional characteristics of TE and TM polarized waves with the polarization response characteristics of the metamaterial microstructure, and achieves independent polarization design through differentiated design of the orthogonal directions of the metamaterial microstructure.

[0082] Optionally, the material of the conductive geometry 2 may include, but is not limited to, gold, silver, copper, etc. For example, the composite layer of substrate 1 and conductive geometry 2 may use the AsG-TL00060UF2 type of new domestic polyimide flexible copper clad laminate from Zhongshan Xingao Electronic Materials Co., Ltd., whose total thickness of polyimide (MPI) film and copper foil is 61um; the width is 500mm; the dielectric constant of the MPI film is <3.0, and the loss tangent is <0.002, which has the characteristics of lower dielectric constant and loss tangent, and smaller amplitude and phase difference of TE and TM polarization. Moreover, the metamaterial structure and radome produced based on this domestic polyimide flexible copper clad laminate obviously greatly improve the security of the supply chain and ensure the normal and safe production of products.

[0083] This invention, through the design of conductive units of different sizes or shapes in the two orthogonal polarization directions TE and TM, achieves relatively independent design and optimization of the electromagnetic response of the other polarization (such as TM) without significantly affecting the electromagnetic response of one polarization (such as TE), thereby realizing relatively independent modulation of the two polarizations.

[0084] Optionally, the shape of the patch includes, but is not limited to, a regular shape (e.g., an ellipse) or an irregular shape (e.g., a polygon).

[0085] According to this invention, the metamaterial structure includes a substrate 1 and a conductive geometric structure 2 disposed on the surface of the substrate 1. The conductive geometric structure 2 includes multiple conductive geometric units 21, each of which includes a patch. The patch includes protruding structures in multiple directions, with the protrusion amplitude in a first direction being greater than that in other directions. The multiple directions include the first direction and other directions. The patch is used to independently modulate the electromagnetic response in the first direction. By adjusting the metamaterial microstructure in one polarization direction, the electromagnetic characteristics in that polarization direction can be optimized, ultimately achieving the goal of independently modulating the electromagnetic response in different polarization directions. Therefore, the problem of not being able to independently modulate the electromagnetic response in different polarization directions in related technologies can be solved.

[0086] In one exemplary embodiment, each conductive geometric unit 21 also includes a connecting loop, with the patch inside the connecting loop and not connected to the connecting loop.

[0087] Optionally, the spatial extent of the conductive geometric unit 21 includes the region enclosed by the connecting loop within the conductive geometric unit 21. For example, as Figure 1 As shown, the protruding structure of the elliptical patch does not contact the connecting loop.

[0088] Optionally, the connecting loop is composed of multiple first bending structures, specifically formed by connecting multiple first bending structures end to end in sequence; or, the connecting loop is composed of multiple straight structures, specifically formed by connecting multiple straight structures end to end in sequence. For example, as... Figure 1 As shown, the straight structure forms a hexagonal conductive geometric unit 21. Elliptical patches are disposed within the connecting loop. The bending form of the first bending structure is not limited; for example, it can be a structure formed by multiple bends or a structure formed by a single bend.

[0089] Optionally, the function of the outer hexagonal connected loop structure is to realize frequency-selective bandpass.

[0090] Furthermore, the connecting loop in this embodiment can be a connected type of bent or wrapped bandpass selector; or a non-connected type of bent or wrapped bandstop selector; it can be customized according to the polarization characteristics or directional characteristics (such as in the ±45° direction), such as locally widening the linewidth in the orthogonal direction of the two polarizations, adding patches, etc., which can be selected and designed according to actual needs; the peripheral structure can be designed differently; one or more layers of metamaterial microstructure can be added as needed.

[0091] In this embodiment, the periodicity control of the metamaterial topology is based on the consideration of suppressing high-frequency grating lobes; the connected loop can shift the frequency-selective resonant frequency to a lower frequency while keeping the period unchanged; the bending form of the structure can be designed to create parasitic resonances as needed; the bending form, period, line width, line spacing, and bending length of the structure together determine the frequency-selective resonant frequency, the rise or fall rate of the lower sideband, and the bandwidth.

[0092] In one exemplary embodiment, the protruding structure includes: an elliptical first protrusion, wherein the first direction is the direction of the major axis of the first protrusion.

[0093] Optionally, such as Figure 1 As shown, the function of the protruding structure is to achieve frequency-selective bandstop. The characteristic of the protruding structure is the differentiated or independent design of the patch structure in the two orthogonal polarization directions, which allows for relatively independent modulation of the two orthogonal polarized waves, achieving polarization equalization optimization or meeting the desired modulation purpose. Furthermore, the period of the patch arrangement and its own dimensions determine the bandstop resonant frequency; the shape of the patch and its relative distance to the surrounding bent ring affect the resonant bandwidth and parasitic resonances. The combination of the outer hexagonal connected ring structure and the patch or ring structure within the unit constitutes a design that allows for adjustable passband or stopband frequency response characteristics at high and low frequencies.

[0094] In addition, the patch unit can be a single patch unit; it can be a ring-shaped (i.e., a patch with a hollowed-out) unit; it can also be any combination of multiple patches, multiple rings, multiple patches + rings, or multiple nested combinations of ring structures and patches, etc.; the internal structure can be designed differently (double-sided); the internal structure can be reduced as needed.

[0095] In this embodiment, various independent or joint modulation requirements can be achieved through a combination of interconnected or disconnected bending or winding or customized design structures in specific directions, plus patch or ring-shaped or ring-shaped nested patches within the unit.

[0096] In an exemplary embodiment, the protruding structure includes a polygonal second protrusion 3, wherein the distance from a first target edge point in the target protrusion direction to the center point of the second protrusion 3 is greater than the distance from a second target edge point in other directions to the center point, the first target edge point is the point farthest from the center point in the target protrusion direction, and the second target edge point is the point farthest from the center point in other directions.

[0097] Optionally, such as Figure 4 The figure shows a plan view of the polygonal second protrusion 3 in the X and Y coordinate directions, where Q is used to represent the intersection deviation value in the X and Y directions.

[0098] The polygonal second protrusion 3 can be a combination structure of a hexagonal ring and a patch. The hexagonal ring can be a structure of six triangular shapes, each containing two conductive structures that are connected. All six triangular structures are connected to the elliptical patch.

[0099] Optionally, the second protrusion 3 includes: a plurality of conductive structures, wherein each conductive structure forms one side of a polygon; a first conductive patch; wherein each conductive structure is connected to the first conductive patch.

[0100] Optionally, each conductive structure includes a plurality of second bending structures, wherein the plurality of second bending structures are connected to the first conductive patch.

[0101] Optionally, the peripheral connected loop structure functions similarly, acting as a bandpass frequency selector. The internal structure functions similarly, acting as a bandstop frequency selector. The structural differences and functional variations mainly lie in the different forms of the internal structure. The functions of this type of design are reflected in: when the unit period is fixed, the high-frequency bandstop resonant frequency can be flexibly designed through flexible structural bending or winding; bending or winding of the ring structure can increase parasitic resonance, realizing functions such as multi-band frequency selection or sideband flat filtering; and through flexible design of the bending or winding of the ring structure and its combination with patch structures, wideband grating lobe suppression can be achieved.

[0102] In one exemplary embodiment, the electromagnetic response in a first direction is modulated by adjusting the parameters of the protruding structure, wherein the parameters of the protruding structure include at least one of the following: shape, size, position, material, and protrusion direction.

[0103] Optionally, the shape can be regular or irregular, the size can be limited according to requirements, the material can be changed according to the substrate material, and the protrusion direction can be determined according to the polarization direction that needs to be adjusted.

[0104] In one exemplary embodiment, the electromagnetic response in the first direction is modulated by adjusting the number of the plurality of conductive geometric units 21 and / or by adjusting the arrangement of the plurality of conductive geometric units 21.

[0105] Optionally, the number and arrangement of geometric units on both sides of the substrate 1 need to be the same.

[0106] In one exemplary embodiment, the patch is obtained by stretching and / or compressing a patch of initial shape.

[0107] Alternatively, for example, Figure 1 The oval patch shown can be based on, for example... Figure 5 The six rotationally symmetric metamaterials shown are obtained through stretching or compression. For example, stretching a circular patch in a connected structure along the horizontal or vertical direction yields an elliptical patch. The connected structure with an outer hexagon and... Figure 1 The connected structures shown have the same function. For example... Figure 5 The figure shows a planar view of the metamaterial in the X and Y coordinate directions, where Q represents the intersection deviation value in the X and Y directions.

[0108] For example, such as Figure 6 The figure shows a planar view of the six-fold rotationally symmetric metamaterial microstructure in the X and Y coordinate directions. Here, Q represents the intersection deviation value in the X and Y directions, d represents the thickness of the metamaterial microstructure, L represents the side length of the metamaterial microstructure, and R represents the diameter of the circular patch in the metamaterial microstructure. The six-fold rotationally symmetric metamaterial microstructure was simulated using the parameters listed in Table 1, with parameter sweeps applied to the scaling factors kx and ky. The S-parameters of the two-fold rotationally symmetric metamaterial microstructure (corresponding to the metamaterial structure mentioned above) and the six-fold rotationally symmetric metamaterial microstructure were obtained through simulation.

[0109] Table 1:

[0110]

[0111] according to Figure 1 and Figure 5The comparative simulations of metamaterial microstructures are as follows:

[0112] 1) For a six-fold rotationally symmetric metamaterial microstructure, set kx = ky, and take values ​​of 0.4, 0.6, 0.8, and 1.0 respectively;

[0113] 2) For a second-order rotationally symmetric metamaterial microstructure, with ky = 0.41 fixed, kx takes values ​​of 0.4, 0.6, 0.8, and 1.0 respectively.

[0114] 3) Frequency range: 0~24GHz;

[0115] 4) Angle of incidence: theta = 70°, phi = 0°;

[0116] 5) Electric field polarization: vertical polarization.

[0117] The simulation yields S11 and S21, specifically for example... Figures 7-12 As shown, the horizontal axis represents frequency (GHz), and the vertical axis represents phase (°). Different curves correspond to different kx and ky values. Figures 7-10 In the figure, the curve value is the insertion phase shift of S21, denoted as IPD. IPD_TE represents the insertion phase shift of S21 under TE polarization. Similarly, IPD_TM represents the insertion phase shift of S21 under TM polarization. Figures 11-12 The values ​​of each curve are the mode phase differences of S21, denoted as IPD_MIX, and its calculation formula includes: IPD_MIX=|IPD_TE-IPD_TM|.

[0118] like Figures 7-12 As shown, the second-order rotationally symmetric metamaterial microstructure is a simple scaling design of the sixth-order rotationally symmetric metamaterial microstructure along the TM polarization direction at different scales. Its impact on TE polarization is minimal, allowing for relatively independent design of TM polarization. Similarly, scaling along the TE polarization direction enables relatively independent control of TE polarization.

[0119] For S11, the simulation results are as follows: Figures 13-16 As shown, the horizontal axis represents frequency in GHz; the vertical axis represents amplitude in decibels (dB). Different curves correspond to different kx and ky values, as detailed in the legend. The curve values ​​represent the S11 amplitude in decibels, with S11_TE representing S11 under TE polarization, and similarly, S11_TM representing S11 under TM polarization. Similarly, from... Figures 13-16 It is evident that the second-order rotational symmetry design allows for relatively independent control of the two polarizations. Furthermore, engineering applications typically focus on the stability of metamaterial microstructures under different incident angles.

[0120] Optionally, S21 inserts a phase shift comparison, such as Figures 17-22 As shown.

[0121] Optionally, the decibel value of the S11 amplitude is, for example... Figure 23-26 As shown.

[0122] from Figures 17-26 It is evident that, for TM polarization, the angular stability of the second-order rotationally symmetric metamaterial microstructure is comparable to that of the conventional sixth-order rotationally symmetric metamaterial microstructure.

[0123] Optionally, Figure 4 The hexagonal patch shown can be based on, for example... Figure 27 The metamaterial shown is obtained by stretching or compressing a material with six rotational symmetries. Figure 27 This is a planar diagram of the metamaterial along the X and Y coordinate directions, where Q represents the intersection deviation value in the X and Y directions. For example, stretching a hexagonal patch in a connected structure along the horizontal or vertical direction yields a stretched hexagonal patch. The connected structure with an outer hexagonal shape and... Figure 4 The connected structures shown have the same function.

[0124] For example, such as Figure 28 The diagram shown is a structural diagram of a six-fold rotationally symmetric metamaterial microstructure. It is a planar view of the metamaterial along the X and Y coordinates, where Q represents the intersection deviation value in the X and Y directions, L represents the side length of the metamaterial microstructure, d represents the thickness of the metamaterial microstructure, gap represents the distance between adjacent triangular structures in the metamaterial microstructure, gap2 represents the distance between two conductive structures in adjacent triangular structures in the metamaterial microstructure, gap3 represents the radius of the patches in the metamaterial microstructure, and w represents the thickness of each bent structure.

[0125] The S-parameters of the six-fold rotationally symmetric metamaterial microstructures were obtained by performing parameter scanning on the scaling factors kx and ky according to the parameters listed in Table 2 and Table 3, respectively, and simulation was performed.

[0126] Table 2:

[0127]

[0128] according to Figure 4 and Figure 27 The specific comparative simulation of the metamaterial microstructure is as follows:

[0129] 1) For a six-fold rotationally symmetric metamaterial microstructure, set kx = ky, and take values ​​of 0.4, 0.6, 0.8, and 1.0 respectively;

[0130] 2) For a second-order rotationally symmetric metamaterial microstructure, with ky = 0.368 fixed, kx takes values ​​of 0.4, 0.6, 0.8, and 1.0 respectively.

[0131] 3) Frequency range: 0~24GHz;

[0132] 4) Angle of incidence: theta = 70°, phi = 0°;

[0133] 5) Electric field polarization: vertical polarization.

[0134] The simulation yields S11 and S21, specifically for example... Figures 29-34 As shown.

[0135] The simulation results of S11 are as follows: Figures 35-38 As shown.

[0136] like Figures 29-38 As shown, the second-order rotationally symmetric metamaterial microstructure is a simple scaling design of the sixth-order rotationally symmetric metamaterial microstructure along the TM polarization direction at different scales. It has little impact on TE polarization and allows for relatively independent design of TM polarization. Similarly, if scaling is performed along the TE polarization direction, relatively independent control of TE polarization can be achieved.

[0137] Stability simulation components under different incident angles Figures 39-48 .

[0138] S21 Insertion Phase Shift Comparison Figures 39-44 As shown.

[0139] Comparison of decibel values ​​of S11 amplitude Figures 45-48 As shown.

[0140] from Figures 39-48 It is evident that, for TM polarization, the angular stability of the second-order rotationally symmetric metamaterial microstructure is comparable to that of the conventional sixth-order rotationally symmetric metamaterial microstructure.

[0141] This embodiment provides an antenna radome, which includes the metamaterial structure described in the above embodiments.

[0142] In summary, this embodiment can achieve relatively independent control of the two polarizations, such as making the IPD of the two polarizations of the sandwich structure approach each other. The most direct application is to improve the electrical performance of the radome, especially the sidelobe level and aiming error. By optimizing the design to obtain a periodic topological structure of the metamaterial microstructure with superior performance in one polarization direction, the electromagnetic characteristics of the other polarization are optimized by independently designing and adjusting the micro-elements of the metamaterial microstructure in the other polarization direction, ultimately achieving independent modulation of the two polarizations.

[0143] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A metamaterial structure, characterized in that, include: substrate; A conductive geometry is disposed on the surface of the substrate; The conductive geometric structure includes multiple conductive geometric units, each of which includes a patch. The patch includes protruding structures that protrude in multiple directions, and the protrusion amplitude of the protruding structures in a first direction is greater than the protrusion amplitude in other directions. The multiple directions include the first direction and the other directions. The patch is used to independently modulate the electromagnetic response in the first direction. The protruding structure includes a polygonal second protrusion, wherein the polygonal second protrusion is a combination structure of a hexagonal ring and a patch. The hexagonal ring consists of six triangular structures, each of which includes two conductive structures that are connected to each other. All six triangular structures are connected to the patch.

2. The metamaterial structure according to claim 1, characterized in that, Each of the conductive geometric units also includes a connecting loop, with the patch inside the connecting loop and not connected to it.

3. The metamaterial structure according to claim 2, characterized in that, The connecting loop is composed of a plurality of first bent structures, or the connecting loop is composed of a plurality of straight structures.

4. The metamaterial structure according to claim 1, characterized in that, The protruding structure includes: An elliptical first protrusion, wherein the first direction is the direction of the major axis of the first protrusion.

5. The metamaterial structure according to claim 1, characterized in that, The first direction includes the target protrusion direction in the second protrusion, wherein the length of the first target edge point in the target protrusion direction from the center point of the second protrusion is greater than the length of the second target edge point in other directions from the center point, the first target edge point is the point farthest from the center point in the target protrusion direction, and the second target edge point is the point farthest from the center point in other directions.

6. The metamaterial structure according to claim 5, characterized in that, The second protrusion includes: Multiple conductive structures, wherein each of the conductive structures forms one side of the polygon; First conductive patch; Each of the conductive structures is connected to the first conductive patch.

7. The metamaterial structure according to claim 6, characterized in that, Each of the aforementioned conductive structures includes: Multiple second bending structures, wherein each of the multiple second bending structures is connected to the first conductive patch.

8. The metamaterial structure according to claim 1, characterized in that, The electromagnetic response in the first direction is modulated by adjusting the parameters of the protruding structure, wherein the parameters of the protruding structure include at least one of the following: shape, size, position, material, and protrusion direction.

9. The metamaterial structure according to claim 1, characterized in that, The electromagnetic response in the first direction is modulated by adjusting the number of the plurality of conductive geometric units and / or by adjusting the arrangement of the plurality of conductive geometric units.

10. The metamaterial structure according to any one of claims 1 to 9, characterized in that, The patch is obtained by stretching and / or compressing a patch of initial shape.

11. A radome, characterized in that, include: The radome comprises the metamaterial structure according to any one of claims 1 to 10.

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