Broadband electromagnetic shielding and wide-angle full-polarization double-window high-transmittance device and parameter configuration method

Abstract

The invention discloses a broadband electromagnetic shielding and wide-angle full-polarization double-window high-transmittance device and a parameter configuration method. The broadband electromagnetic shielding and wide-angle full-polarization double-window high-transmittance device comprises a plurality of structural units which are periodically arranged along a plane, each structural unit comprises an insulating substrate, a square metal outer frame, a first metal structure and a second metal structure, the bottom of the metal outer frame is fixed on the insulating substrate, and a mounting cavity is defined in the middle of the metal outer frame; the bottom of the first metal structure is mounted on the insulating substrate and accommodated in the mounting cavity, the first metal structure and the inner wall of the mounting inner cavity are arranged at an interval, the first metal structure comprises a regular cross structure and four first connecting rods with the same length, the center of the regular cross structure coincides with the center of the metal outer frame, and the four first connecting rods are connected with the inner wall of the mounting inner cavity. Each end part of the regular cross-shaped structure is vertically connected with a first connecting rod, and the central position of each first connecting rod is connected and vertical to the end part of the corresponding regular cross-shaped structure.

Description

Technical Field

[0001] The present invention relates to the field of electronic technologies, and in particular, to a broadband electromagnetic shielding and wide-angle full-polarization dual-window high-transmission device and a parameter configuration method thereof. Background Art

[0002] The free regulation of electromagnetic waves has always been the dream and pursuit of mankind. The research on this issue not only has important basic scientific significance, but also has important application values in many fields such as the information industry, national defense security, biomedicine, and energy. However, natural materials are composed of a limited variety of atoms and structural forms, and their electromagnetic response parameters can only take a very limited range. Therefore, the ability of natural materials to regulate electromagnetic waves is very limited.

[0003] With the rapid development of modern micro-nano manufacturing technologies and materials science, the electromagnetic metasurface technology is gradually becoming an important platform for realizing the precise regulation of electromagnetic waves. An electromagnetic metasurface is composed of a series of sub-wavelength artificial atoms (meta-atoms) arranged in a certain two-dimensional macroscopic sequence. By finely designing the microstructures at the sub-wavelength scale, the effective control of the amplitude, phase, and polarization state of the incident electromagnetic waves can be achieved locally. Among them, the regulation of the shielding and windowing performance of electromagnetic metasurfaces for electromagnetic waves shows broad application prospects in fields such as wireless communication and radar stealth.

[0004] Currently, traditional radar stealth technologies mainly achieve stealth by fabricating a metal mesh structure composed of excellent conductive metals on the material surface, and the main electromagnetic wave band targeted is the centimeter wave in the 2-18 GHz frequency band. In recent years, with the vigorous development and advancement of anti-stealth technologies, the requirements for radar stealth performance are developing towards "ultra-wideband" and "high efficiency". At the same time, in order to cope with actual complex application scenarios and facilitate combination with other devices, while achieving broadband and high-efficiency stealth, it is often necessary to ensure the normal high transmission of electromagnetic waves at specific multiple frequency windows.

[0005] However, traditional metasurface devices usually achieve specific functions within a single operating frequency band, such as single-window transmission or reflection regulation, and cannot achieve the normal high transmission of electromagnetic waves at specific multiple frequency windows.

[0006] The above content is only used to assist in understanding the technical solution of the present invention, and does not represent an admission that the above content is prior art. Summary of the Invention

[0007] The main objective of the present invention is to provide a broadband electromagnetic shielding and wide-angle full-polarization dual-window high-transmission device and a parameter configuration method thereof, aiming to solve the technical problem that traditional metasurface devices usually achieve specific functions within a single operating frequency band and cannot achieve the normal high transmission of electromagnetic waves at specific multiple frequency windows in the prior art.

[0008] To achieve the above objectives, the present invention provides a broadband electromagnetic shielding and wide-angle full-deflection dual-window high-transmittance device based on a mortise and tenon structure metasurface. The broadband electromagnetic shielding and wide-angle full-deflection dual-window high-transmittance device based on a mortise and tenon structure metasurface comprises a plurality of structural units periodically arranged along a plane, each structural unit comprising:

[0009] insulating substrate;

[0010] A square metal outer frame, the bottom of which is fixed on the insulating substrate and the middle of which is surrounded by a mounting cavity;

[0011] a first metal structure, the bottom of which is mounted on the insulating substrate and accommodated in the mounting cavity, and is spaced apart from the inner wall of the mounting cavity, the first metal structure comprising a right-angled cross structure and four first connecting rods of equal length, the center of the right-angled cross structure coinciding with the center of the metal outer frame, each end of the right-angled cross structure being perpendicularly connected to a first connecting rod, the first connecting rod being connected to and perpendicular to the corresponding end of the right-angled cross structure at its center, each first connecting rod being parallel to an adjacent side of the metal outer frame, and the four first connecting rods being spaced apart and surrounding a mounting sub-cavity;

[0012] a second metal structure, the bottom of which is mounted on the insulating substrate and accommodated in the mounting sub-cavity, and is spaced apart from the inner wall of the mounting sub-cavity, the second metal structure comprising an oblique cross structure and four identical right-angle structures, each right-angle structure comprising two second connecting rods of equal length and vertically connected at ends, the oblique cross structure comprising two metal rods of equal length, vertically connected at the center, the center of the oblique cross structure coincides with the center of the metal outer frame and is located on a diagonal of the metal outer frame, and each end of the oblique cross structure is connected to a right-angle structure and is located at the middle of an inner corner of the right-angle structure;

[0013] The regular cross structure and the oblique cross structure are cross-arranged at the center position through a giving way structure and do not contact each other.

[0014] Preferably, in the broadband electromagnetic shielding and wide-angle full-deviation dual-window high-transmittance device based on the mortise and tenon structure metasurface, the regular cross structure includes a first metal rod and a second metal rod of equal length, connected at the center and perpendicular to each other, and the oblique cross structure includes a third metal rod and a fourth metal rod of equal length, connected at the center and perpendicular to each other;

[0015] Among them, the length of the first metal rod and the second metal rod is L1, the length of the first connecting rod is L2, the length of the third metal rod and the fourth metal rod is L3, and the length of the second connecting rod is L4. The frequency corresponding to L1+L2 matches the low frequency of the two set target operating frequencies, and the frequency corresponding to L3+L4 matches the high frequency of the two set target operating frequencies.

[0016] Preferably, in the broadband electromagnetic shielding and wide-angle full-deviation dual-window high-transmittance device based on the mortise and tenon structure metasurface, the give-way structure is a first give-way groove structure arranged at the center position of the oblique cross structure, or a second give-way groove structure arranged at the center position of the regular cross structure.

[0017] Preferably, in the broadband electromagnetic shielding and wide-angle full-deviation dual-window high-transmittance device based on the mortise and tenon structure metasurface, the clearance structure is a first clearance groove structure, the oblique cross structure includes a third metal rod and a fourth metal rod, and the center positions of the third metal rod and the fourth metal rod are respectively provided with a first groove and a second groove of the same length, and the first groove and the second groove are connected together at the center of the metal outer frame to form an installation space;

[0018] The center of the regular cross structure is accommodated in the installation space and does not contact the inner wall of the installation space.

[0019] Preferably, in the broadband electromagnetic shielding and wide-angle full-deviation double-window high-transmittance device based on the mortise and tenon structure metasurface, the depth from the bottom of the first groove to the bottom of the third metal rod and the depth from the bottom of the second groove to the bottom of the fourth metal rod are both D2, 0.005mm≤D2≤0.05mm.

[0020] Preferably, in the broadband electromagnetic shielding and wide-angle full-deviation double-window high-transmittance device based on the mortise and tenon structure metasurface, the length of the first groove along the length direction of the third metal rod and the length of the second groove along the length direction of the fourth metal rod are both L5, and L5 is 0.2 mm.

[0021] Preferably, in the broadband electromagnetic shielding and wide-angle full-deviation double-window high-transmittance device based on the mortise and tenon structure metasurface, the distance between each first connecting rod and the wall surface of the edge of the adjacent metal outer frame is D1, 0.05mm≤D1≤0.15mm.

[0022] Preferably, in the broadband electromagnetic shielding and wide-angle full-deviation double-window high-transmittance device based on the mortise and tenon structure metasurface, the thickness of the insulating substrate is H1, 1mm≤H1≤5mm.

[0023] Preferably, in the broadband electromagnetic shielding and wide-angle full polarization double-window high-transmittance device based on the mortise-tenon structure metasurface, the thickness of the metal outer frame in the length direction is H2, and the width of the metal outer frame is W, where 0.05 mm ≤ H2 ≤ 0.2 mm and 2 mm ≤ W ≤ 6 mm.

[0024] To achieve the above object, the present invention also provides a parameter configuration method for the above-mentioned broadband electromagnetic shielding and wide-angle full polarization double-window high-transmittance device based on the mortise-tenon structure metasurface, which is characterized in that the parameter configuration method for each structural unit includes:

[0025] Step S210, take the width of the metal outer frame within a preset range, where the preset range is from 2 mm to 6 mm;

[0026] Step S220, calculate the length ranges of the first metal rod and the second metal rod. Among them, the distance D1 between the first connecting rod and the corresponding side of the metal outer frame is 0.05 mm - 0.15 mm. Take the maximum value of the lengths L1 of the first metal rod and the second metal rod, and then select the value of the length L2 of the first connecting rod so that the frequency corresponding to L1 + L2 matches the lower frequency of the two set target operating frequencies;

[0027] Step S230, determine whether the frequency corresponding to L1 + L2 matches the lower frequency of the two set target operating frequencies, and obtain a first judgment result;

[0028] Step S240, when the first judgment result is yes, calculate the length ranges of the third metal rod and the fourth metal rod. Among them, the lengths L3 of the third metal rod and the fourth metal rod satisfy L1 ≤ L3 ≤ 1.3 * L1. Take the maximum value of the lengths L3 of the third metal rod and the fourth metal rod, and then select the value of the length L4 of the second connecting rod so that the frequency corresponding to L3 + L4 matches the higher frequency of the two target operating frequencies; otherwise, return to step S210 to reconfigure;

[0029] Step S250, determine whether the frequency corresponding to L3 + L4 matches the higher frequency of the two target operating frequencies, and obtain a second judgment result;

[0030] Step S260, when the second judgment result is yes, the parameter configuration is completed; otherwise, return to step S210 to reconfigure.

[0031] The present invention has at least the following beneficial effects:

[0032] The present invention provides a broadband electromagnetic shielding and wide-angle full-deflection double-window high-transmittance device based on a mortise and tenon structure metasurface. The broadband electromagnetic shielding and wide-angle full-deflection double-window high-transmittance device includes a plurality of structural units periodically arranged along a plane, each structural unit includes an insulating substrate, a square metal outer frame, and a first metal structure. The bottom of the metal outer frame is fixed on the insulating substrate and a mounting cavity is formed in the middle; the bottom of the first metal structure is mounted on the insulating substrate and accommodated in the mounting cavity, and is spaced apart from the inner wall of the mounting cavity. The first metal structure includes a right-cross structure and four first connecting rods of equal length. The center of the right-cross structure coincides with the center of the metal outer frame. Each end of the right-cross structure is vertically connected to a first connecting rod. The first connecting rod is connected to and perpendicular to the corresponding end of the right-cross structure at its center position. Each first connecting rod is arranged parallel to the adjacent side of the metal outer frame. The four first connecting rods are spaced apart and surrounded. The invention relates to a device comprising a mounting sub-cavity; a second metal structure having a bottom mounted on the insulating substrate and contained within the mounting sub-cavity and spaced apart from the inner wall of the mounting sub-cavity; the second metal structure comprising an oblique cross structure and four identical right-angle structures, each right-angle structure comprising two second connecting rods of equal length and perpendicularly connected at the ends; the oblique cross structure comprising two metal rods of equal length and perpendicularly connected at the center; the center of the oblique cross structure coincides with the center of the metal outer frame and is located on a diagonal of the metal outer frame; each end of the oblique cross structure is connected to a right-angle structure and is located at the middle of the inner corner of the right-angle structure; wherein the right cross structure and the oblique cross structure are arranged in a cross-position at the center through a yield structure and do not contact each other, so that the electromagnetic metasurface can be used to achieve broadband shielding from 200MHz to 33GHz, while opening two windows at a specific frequency point, and having stable high transmittance for different incident angles and polarizations. Compared with previous metasurface devices, the design proposed in the present invention has the advantages of wide bandwidth, dual windows, large angle, and full polarization.

[0033] Furthermore, the metal frame, the first metal structure, and the second metal structure do not contact each other. Such a resonant structure utilizes the back-and-forth oscillation of the induced current inside the metal structure to store energy. If the internal first metal structure and the second metal structure are in contact and connected with the outer metal frame, the induced current on the first metal structure and the second metal structure will carry energy and propagate to the outer metal frame, causing the resonant mode to be unable to be excited; if the internal first metal structure and the second metal structure are in contact and connected with each other, then when the resonant mode is excited, the induced currents on the first metal structure and the second metal structure will interfere with each other, triggering additional resonant modes and reducing device performance.

[0034] Furthermore, the metal outer frame, the first metal structure, and the second metal structure should all adopt structures with four-fold symmetry characteristics to ensure the four-fold symmetry characteristics of the overall metasurface device. Taking the metasurface plane as the xoy plane, the incident wave in any direction in space can be decomposed into the superposition of incident waves with wave vectors located in the xoz and yoz planes. When the metasurface has four-fold symmetry characteristics, since the incident situations in the xoz and yoz planes are exactly the same, the designed metasurface only needs to maintain stable shielding and high-transmission performance for TE and TM polarizations with wave vectors incident in the xoz plane, that is, it can maintain stable shielding and high-transmission performance for incident waves in the entire space.

[0035] Furthermore, traditional radar stealth structures often only have the ability to shield electromagnetic waves, and the shielding bandwidth is limited. Based on optimizing the metal outer frame to achieve more broadband electromagnetic shielding, the present invention adds tenon-mortise type metal resonance structures (the first metal structure and the second metal structure) to the structure to achieve high transmission in two specific frequency windows; and the device performance has the characteristics of large angle and full polarization, and can maintain good performance for incident waves from all directions in the actual application scenario. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 Schematic diagram of an embodiment of a broadband electromagnetic shielding and wide-angle full-polarization double-window high-transmission device provided by the present invention;

[0037] Figure 2 is Figure 1 Schematic diagram of each structural unit in;

[0038] Figure 3 is Figure 2 Cross-sectional view at a perspective;

[0039] Figure 4 is Figure 3 Partial schematic diagram of the first metal structure in;

[0040] Figure 5 is Figure 3 Partial schematic diagram of the second metal structure in;

[0041] Figure 6 is Figure 5 Schematic diagram at another perspective;

[0042] Figure 7 Flowchart of the method for determining each parameter of each structural unit in the metasurface system for realizing electromagnetic shielding and transmission window based on mode coupling provided by the present invention;

[0043] Figure 8 Transmission spectra of the metasurface system for realizing electromagnetic shielding and transmission window based on mode coupling provided by the present invention at different angles and polarizations, with the ordinate using linear coordinates;

[0044] Figure 9 The transmission spectra of the metasurface system for realizing electromagnetic shielding and transmission window based on mode coupling provided by the present invention at different angles and polarizations, with the ordinate using logarithmic coordinates.

[0045] 1000 - Wideband electromagnetic shielding and wide - angle full - polarization double - window high - transmission device, 100 - Structural unit, 1 - Insulating substrate, 2 - Metal outer frame, 21 - First frame member, 22 - Second frame member, 23 - Third frame member, 24 - Fourth frame member, 3 - First metal structure, 31 - Positive cross structure, 311 - First metal rod, 312 - Second metal rod, 321 - First rod, 322 - Second rod, 323 - Third rod, 324 - Fourth rod, 4 - Second metal structure, 41 - Oblique cross structure, 411 - Third metal rod, 4111 - First groove, 412 - Fourth metal rod, 4121 - Second groove, 421 - First right - angle structure, 4211 - Fifth rod, 4212 - Sixth rod, 422 - Second right - angle structure, 4221 - Seventh rod, 4222 - Eighth rod, 423 - Third right - angle structure, 4231 - Ninth rod, 4232 - Tenth rod, 424 - Fourth right - angle structure, 4241 - Eleventh rod, 4242 - Twelfth rod.

[0046] The implementation, functional features and advantages of the present invention will be further described with reference to the embodiments and the accompanying drawings. Detailed implementation manners

[0047] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are some but not all of the embodiments of the present invention. The present invention will be described in detail below with reference to the drawings and embodiments. It should be noted that, without conflict, the embodiments in the present invention and the features in the embodiments can be combined with each other.

[0048] In the embodiments of the present invention, the term "and / or" describes the association relationship of associated objects, indicating that there can be three relationships. For example, A and / or B can represent: A exists alone, A and B exist simultaneously, and B exists alone. The character " / " generally represents an "or" relationship between the associated objects before and after.

[0049] It should be noted that the terms "first", "second", etc. in the description and claims of the present invention and the above - mentioned drawings are used to distinguish similar objects and do not necessarily describe a specific order or sequence.

[0050] In the embodiments of the present invention, the term "plural" means two or more, and other quantifiers are similar thereto.

[0051] In the present invention, unless otherwise specified, the orientation terms such as "upper, lower, top, bottom" generally refer to the directions shown in the drawings, or to the vertical, perpendicular or gravitational directions of the components themselves; similarly, for the convenience of understanding and description, "inner, outer" refer to the inner and outer of the contours of the respective components themselves, but the above orientation terms are not used to limit the present invention.

[0052] To make the objectives, technical solutions and advantages of the embodiments of the present invention clearer, the embodiments of the present invention will be described in detail below with reference to the drawings. However, those of ordinary skill in the art can understand that in the embodiments of the present invention, many technical details are provided for the readers to better understand the present invention. However, even without these technical details and various changes and modifications based on the following embodiments, the technical solutions claimed by the present invention can still be implemented. The following division of each embodiment is for convenience of description and should not constitute any limitation to the specific implementation manner of the present invention. Each embodiment can be combined and cross-referenced with each other on the premise of no contradiction.

[0053] To solve the above problems, please refer to Figure 1 , the present invention provides a broadband electromagnetic shielding and wide-angle full polarization double-window high-transmission device 1000 based on a mortise-tenon structure metasurface. The broadband electromagnetic shielding and wide-angle full polarization double-window high-transmission device based on the mortise-tenon structure metasurface includes a plurality of structural units arranged periodically along a plane. Please refer to Figure 2 and Figure 3 , each structural unit 100 includes an insulating substrate 1, a square metal outer frame 2, a first metal structure 3, and a second metal structure 4.

[0054] It should be noted that the broadband electromagnetic shielding and wide-angle full polarization double-window high-transmission device 1000 based on the mortise-tenon structure metasurface includes a plurality of structural units 100 arranged periodically along a plane, which may be hundreds or even thousands of structural units 100 arranged periodically in the x direction and the y direction, and no specific limitation is made here. In this embodiment, the broadband electromagnetic shielding and wide-angle full polarization double-window high-transmission device 1000 based on the mortise-tenon structure metasurface includes 137*137 structural units 100 arranged in the x and y directions, with a length and width of 328.8mm*328.8mm.

[0055] The insulating substrate 1 is used to fix the metal outer frame 2, the first metal structure 3, and the second metal structure 4. The metal outer frame 2, the first metal structure 3, and the second metal structure 4 can be buried on the surface of the insulating substrate 1. In some embodiments, the insulating substrate 1 may be a dielectric plate with a relative dielectric constant of 3.3 and a thickness of 4.4mm. In some other embodiments, the insulating substrate 1 can also be any insulating material.

[0056] Among them, the insulating substrate 1 will cause the FP effect, resulting in additional resonance modes. Among them, the FP effect means that when electromagnetic waves are incident on the insulating substrate 1 with a certain thickness, there are not only two transmissions and reflections, but there will be multiple transmissions and reflections at the upper and lower interfaces of the insulating substrate 1. Finally, the reflection and transmission signals in the air on both sides are the interference superposition of this series of signals.

[0057] Among them, when the resonance frequency of the FP resonance mode is close to the resonance frequency of the mortise and tenon metal resonance structure of the target, it will seriously interfere with the original high-transmission performance. Therefore, it is necessary to reduce the influence of the FP effect by adjusting the thickness of the insulating substrate 1. When the thickness of the insulating substrate 1 is thicker, the resonance mode of FP will move towards the low-frequency direction; when the thickness of the insulating substrate 1 is thinner, the resonance mode of FP will move towards the high-frequency direction. Therefore, the thickness of the insulating substrate 1 can be adjusted according to the two target operating frequencies, neither too thick nor too thin. In some embodiments, the thickness of the insulating substrate 1 is H1, and 1mm ≤ H1 ≤ 5mm. In some other embodiments, the thickness of the insulating substrate 1 can be adjusted according to the actual frequency position of the target window opening.

[0058] The metal outer frame 2 can shield electromagnetic waves. This is mainly because when the mesh size is much smaller than the wavelength, the metal outer frame 2 behaves more like a continuous and equivalent conductor plane; at this time, due to the impedance discontinuity, most of the electromagnetic waves will be reflected back when incident on the surface of the metal outer frame 2, thus preventing the propagation of electromagnetic waves.

[0059] The mesh size formed by the metal outer frame 2 should be much smaller than the wavelength. Since the first metal structure 3 and the second metal structure 4 will be placed inside the metal outer frame 2, and the generally studied frequency band is 200MH1 z - 33GH1 z, the thickness of the metal outer frame 2 along the length direction is H2, and 0.05mm ≤ H2 ≤ 0.2mm. Therefore, the width W of the metal outer frame 2 cannot be arbitrarily small. If the width W of the metal outer frame 2 is too small, high-frequency electromagnetic waves will be more likely to penetrate the metal outer frame 2; if the width W of the metal outer frame 2 is too large, it will affect the shielding performance, and the larger the width W of the metal outer frame 2, the worse the shielding performance. Therefore, when the width W of the metal outer frame 2 cannot be further reduced, the width W of the metal outer frame 2 can be appropriately increased. Therefore, in some embodiments, the width W of the metal outer frame 2 can generally be selected between 2mm and 6mm.

[0060] The bottom of the metal outer frame 2 is fixed on the insulating substrate 1 and an installation cavity is formed in the middle by surrounding. The installation cavity is used for installing the first metal structure 3 and the second metal structure 4. The structural unit 100 provided by the present invention is a square structural unit and can be arranged periodically along the x and y directions. A plurality of metal outer frames 2 are arranged at intervals of p along the width direction and the length direction respectively. In this way, a plurality of metal square holes with a side length of (W - 2*H2) can be formed with a period of p. Thus, the shielding performance of the structure against electromagnetic waves can be adjusted by adjusting the width W of the metal outer frame 2 and the thickness H2 of the metal outer frame 2 along the length direction. The metal outer frame 2 includes a first frame member 21, a second frame member 22, a third frame member 23, and a fourth frame member 24 that are sequentially connected together to form a square, and the sizes of the first frame member 21 to the fourth frame member 24 are the same.

[0061] The metal outer frame 2 brings a broadband shielding background with negative permittivity, and the first metal structure 3 and the second metal structure 4 bring a positive permittivity response resonance at a specific frequency. After superimposing the two structures, the overall permittivity of the synthesis will be close to the permittivity of air at a specific frequency point. At this time, impedance matching is achieved and the electromagnetic high-transmission effect is realized.

[0062] Please refer to Figure 3 and Figure 4 , the bottom of the first metal structure 3 is installed on the insulating substrate 1 and is accommodated in the installation cavity, and is spaced from the inner wall of the installation inner cavity. The first metal structure 3 includes a positive cross structure 31 and four first connecting rods with equal lengths. The center of the positive cross structure 31 coincides with the center of the metal outer frame 2. Each end of the positive cross structure 31 is vertically connected with a first connecting rod. The first connecting rod is connected to and perpendicular to the corresponding end of the positive cross structure 31 at its central position. Each first connecting rod is arranged parallel to the adjacent side of the metal outer frame 2. The four first connecting rods are all arranged at intervals and an installation sub-cavity is formed by surrounding.

[0063] It should be noted that the first metal structure 3 is spaced from the inner wall of the installation inner cavity, which means that each component of the first metal structure 3 does not contact the metal outer frame 2, neither the positive cross structure 31 nor the four first connecting rods contact the metal outer frame 2.

[0064] The positive cross structure 31 includes a first metal rod 311 and a second metal rod 312 that are equal in length and are connected and perpendicular to each other at the center. The first metal rod 311 and the second metal rod 312 are cross-connected together at the central position. In some embodiments, the first metal rod 311 and the second metal rod 312 may be integrally arranged; in some other embodiments, the first metal rod 311 and the second metal rod 312 may be independently arranged and cross-connected at the central position.

[0065] The first metal rod 311 is perpendicular to and located at the middle position of two opposite sides of the metal outer frame 2. The second metal rod 312 is perpendicular to and located at the middle position of the other two opposite sides of the metal outer frame 2. For example, the first metal rod 311 is perpendicular to and located at the middle position of the first frame member 21 and the third frame member 23. The second metal rod 312 is perpendicular to and located at the middle position of the second frame member 22 and the fourth frame member 24. Herein, the first metal rod 311 does not contact the first frame member 21 and the third frame member 23, and the second metal rod 312 does not contact the second frame member 22 and the fourth frame member 24.

[0066] The four first connecting rods are respectively the first rod 321, the second rod 322, the third rod 323, and the fourth rod 324. The two ends of the first metal rod 311 are respectively and perpendicularly connected to the first rod 321 and the third rod 323, and the first rod 321 and the third rod 323 are respectively connected to the first metal rod 311 at their midpoints. The two ends of the second metal rod 312 are respectively and perpendicularly connected to the second rod 322 and the fourth rod 324, and the second rod 322 and the fourth rod 324 are respectively connected to the second metal rod 312 at their midpoints. When the first metal rod 311 is perpendicular to and located at the middle position of the first frame member 21 and the third frame member 23, and the second metal rod 312 is perpendicular to and located at the middle position of the second frame member 22 and the fourth frame member 24, the first rod 321 and the third rod 323 are respectively arranged parallel to the first frame member 21 and the third frame member 23, and the second rod 322 and the fourth rod 324 are respectively arranged parallel to the second frame member 22 and the fourth frame member 24. The first rod 321 is arranged not to contact the first frame member 21, the second rod 322 is arranged not to contact the second frame member 22, the third rod 323 is arranged not to contact the third frame member 23, and the fourth rod 324 is arranged not to contact the fourth frame member 24.

[0067] It should be noted that adjacent ones among the first rod 321, the second rod 322, the third rod 323, and the fourth rod 324 do not contact each other either.

[0068] The frequencies of the high-transmission windows corresponding to the first metal structure 3 and the second metal structure 4 respectively, where the first metal structure 3 corresponds to the lower operating frequency of the two operating frequencies. Since the longer the first metal rod 311, the second metal rod 312, and the first connecting rod in the first metal structure 3 are, the longer the resonance wavelength is and the lower the resonance frequency is, the position of the lower operating frequency of the two operating frequencies can be adjusted by adjusting the lengths of the first metal rod 311, the second metal rod 312, and the first connecting rod. The distance between each first connecting rod and the wall surface of the side of the adjacent metal outer frame 2 is D1. If D1 is too large, it will limit the lengths of the first metal rod 311, the second metal rod 312, and the first connecting rod to be too small; and each first connecting rod cannot be in contact with the wall surface of the side of the adjacent metal outer frame 2, so D1 cannot be too small either, to avoid contact caused by poor control. In some embodiments, 0.05 mm ≤ D1 ≤ 0.15 mm.

[0069] In some embodiments, the materials of the first metal rod 311, the second metal rod 312, and the first connecting rod are copper; in some other embodiments, the materials of the first metal rod 311, the second metal rod 312, and the first connecting rod can also be other metals, which can be set according to specific needs.

[0070] The first metal structure 3 opens the first target transmission window at a specific frequency and can achieve high transmission. This is mainly because the resonance structure will excite local resonance at a certain specific frequency, causing the induced current to oscillate back and forth inside the first metal structure 3, so that the input electromagnetic energy is locally stored. When the frequency of the external electromagnetic wave matches the resonance frequency, the energy carried by the incident wave can be coupled into the structure and transmitted to the other side of the shield through the resonance mode, thus achieving high transmission.

[0071] Please refer to Figure 3 、 Figure 5 and Figure 6 , the bottom of the second metal structure 4 is mounted on the insulating substrate 1 and is received in the mounting sub-cavity, and is spaced from the inner wall of the mounting sub-cavity. The second metal structure 4 includes an inclined cross structure 41 and four identical right-angle structures. Each right-angle structure includes two second connecting rods with equal lengths and perpendicular to each other at the ends. The inclined cross structure 41 includes two metal rods with the same length and perpendicular to each other and connected together at the center position. The center of the inclined cross structure 41 coincides with the center of the metal outer frame 2 and is located on the diagonal line of the metal outer frame 2. Each end of the inclined cross structure 41 is connected to a right-angle structure and is located at the middle position of the inner angle of the right-angle structure.

[0072] It should be noted that the second metal structure 4 is spaced from the inner wall of the installation sub-cavity, which means that each component of the second metal structure 4 does not contact any component of the first metal structure 3, whether it is the first metal rod 311 and the second metal rod 312, or the four second connecting rods, none of them contact the second metal structure 4.

[0073] The oblique cross structure 41 includes a third metal rod 411 and a fourth metal rod 412 that are equal in length, connected at the center and perpendicular to each other. The third metal rod 411 and the fourth metal rod 412 are cross-connected at the center. In some embodiments, the third metal rod 411 and the fourth metal rod 412 may be integrally provided; in some other embodiments, the third metal rod 411 and the fourth metal rod 412 may be independently provided and cross-connected at the center.

[0074] The center of the oblique cross structure 41 coincides with the center of the metal outer frame 2 and is located on the diagonal of the metal outer frame 2. It can be understood that the center of the third metal rod 411 coincides with the center of the metal outer frame 2 and is located on one diagonal of the metal outer frame 2, and the center of the fourth metal rod 412 coincides with the center of the metal outer frame 2 and is located on the other diagonal of the metal outer frame 2.

[0075] The four right-angle structures are respectively a first right-angle structure 421, a second right-angle structure 422, a third right-angle structure 423, and a fourth right-angle structure 424. The first right-angle structure 421 includes a fifth rod 4211 and a sixth rod 4212, the second right-angle structure 422 includes a seventh rod 4221 and an eighth rod 4222, the third right-angle structure 423 includes a ninth rod 4231 and a tenth rod 4232, and the fourth right-angle structure 424 includes an eleventh rod 4241 and a twelfth rod 4242, where the lengths of the fifth rod 4211 to the twelfth rod 4242 are all equal.

[0076] One end of the third metal rod 411 is connected to the fifth rod 4211 and the sixth rod 4212. The fifth rod 4211 and the sixth rod 4212 are respectively located on both sides of the third metal rod 411, and the included angles between the fifth rod 4211 and the sixth rod 4212 and the third metal rod 411 are both 45 degrees; the other end of the third metal rod 411 is connected to the ninth rod 4231 and the tenth rod 4232. The ninth rod 4231 and the tenth rod 4232 are respectively located on both sides of the third metal rod 411, and the included angles between the ninth rod 4231 and the tenth rod 4232 and the third metal rod 411 are both 45 degrees. One end of the fifth rod 4211 and the sixth rod 4212, the ninth rod 4231 and the tenth rod 4232 are all connected to the third metal rod 411, and the other ends extend inward respectively.

[0077] One end of the fourth metal rod 412 is connected to a seventh rod 4221 and an eighth rod 4222. The seventh rod 4221 and the eighth rod 4222 are located on either side of the fourth metal rod 412, and each rod forms a 45-degree angle with the fourth metal rod 412. The other end of the fourth metal rod 412 is connected to an eleventh rod 4241 and a twelfth rod 4242. The eleventh rod 4241 and the twelfth rod 4242 are located on either side of the fourth metal rod 412, and each rod forms a 45-degree angle with the fourth metal rod 412. The seventh rod 4221 and the eighth rod 4222, as well as the eleventh rod 4241 and the twelfth rod 4242, are all connected to the fourth metal rod 412, and their other ends extend inward.

[0078] The second metal structure 4 opens a second target transmission window at a specific frequency. The reason for achieving high transmittance can be referred to the principle of the first metal structure 3 and will not be elaborated here. It should be noted that the first metal structure 3 and the second metal structure 4 do not contact each other. The right cross structure 31 and the oblique cross structure 41 are arranged in a cross-shaped arrangement at the center, with a clearance structure, and do not contact each other.

[0079] In some embodiments, the give way structure is a first give way groove structure provided at the center position of the oblique cross structure 41, and the center position of the regular cross structure 31 is accommodated in the first give way groove structure and does not contact the wall surface of the first give way groove structure; in some other embodiments, the give way structure can also be a second give way groove structure provided at the center position of the regular cross structure 31, and the center position of the oblique cross structure 41 is accommodated in the second give way groove structure and does not contact the inner wall of the second give way groove structure.

[0080] For illustration, the first clearance groove structure, located at the center of the oblique cross structure 41, is used as an example. A first groove 4111 and a second groove 4121 of equal length are respectively defined at the center of the third metal rod 411 and the fourth metal rod 412. The first groove 4111 and the second groove 4121 are connected at the center of the metal outer frame 2 to form an installation space. The center of the right cross structure 31 is accommodated within the installation space and does not contact the inner walls of the installation space. It is important to emphasize that the first groove 4111 does not extend through the third metal rod 411, and the second groove 4121 does not extend through the fourth metal rod 412. The depth from the bottom of the first groove 4111 to the bottom of the third metal rod 411 is D2, which is the depth remaining after the third metal rod 411 is removed. The depth from the bottom of the second groove 4121 to the bottom of the fourth metal rod 412 is also D2, which is the depth remaining after the fourth metal rod 412 is removed. In some embodiments, D2 is between 0.005 mm and 0.05 mm.

[0081] The length of the first slot 4111 along the length direction of the third metal rod 411 is L5, and the length of the second slot 4121 along the length direction of the fourth metal rod 412 is also L5. L5 should be as small as possible while ensuring that the first metal rod 311 and the second metal rod 312 do not contact the third metal rod 411 and the fourth metal rod 412. If it is too large, it will cause a decrease in the intensity of the resonance peak of the operating frequency of the diagonal cross structure 41, and the corresponding resonance peak transmittance will decrease. In some embodiments, L5 is 0.2 mm.

[0082] The metal outer frame 2, the first metal structure 3, and the second metal structure 4 do not contact each other. In this way, the resonance structure utilizes the back-and-forth oscillation of the induced current inside the metal structure to store energy. If the internal first metal structure 3 and the second metal structure 4 are in contact and connected to the outer metal outer frame 2, the induced current on the first metal structure 3 and the second metal structure 4 will carry energy and propagate into the outer metal outer frame 2, resulting in the inability to excite the resonance mode; if the internal first metal structure 3 and the second metal structure 4 are in contact and connected to each other, when the resonance mode is excited, the induced current on the first metal structure 3 and the second metal structure 4 will interfere with each other, triggering an additional resonance mode and reducing the device performance.

[0083] In addition, the metal outer frame 2, the first metal structure 3, and the second metal structure 4 should all adopt structures with four-fold symmetry characteristics to ensure the four-fold symmetry characteristics of the overall metasurface device. Taking the metasurface plane as the xoy plane, an incident wave in any direction in space can be decomposed into the superposition of incident waves with wave vectors in the xoz and yoz planes. When the metasurface has four-fold symmetry characteristics, since the incident situations in the xoz and yoz planes are exactly the same, the designed metasurface only needs to maintain stable shielding and high-transmission performance for TE and TM polarizations of incident waves with wave vectors in the xoz plane, that is, it can maintain stable shielding and high-transmission performance for incident waves in the entire space.

[0084] The present invention also provides a parameter configuration method for a broadband electromagnetic shielding and wide-angle full-polarization double-window high-transmission device based on a mortise-and-tenon structure metasurface. Figure 7 Schematically shows a schematic diagram of an embodiment of the parameter configuration method for a broadband electromagnetic shielding and wide-angle full-polarization double-window high-transmission device based on a mortise-and-tenon structure metasurface of the present invention. Please refer to Figure 7 , for the parameter configuration method of each structural unit in the broadband electromagnetic shielding and wide-angle full-polarization double-window high-transmission device based on a mortise-and-tenon structure metasurface, the parameter configuration method for the broadband electromagnetic shielding and wide-angle full-polarization double-window high-transmission device based on a mortise-and-tenon structure metasurface can directly refer to the parameter configuration method of each structural unit.

[0085] In step S210, the width of the metal outer frame 2 is taken within a preset range, where the preset range is from 2 mm to 6 mm. First, a width of the metal outer frame 2 is selected within the preset range, which can be a randomly selected value or selected according to a certain rule, such as selecting values from large to small or from small to large at a certain interval.

[0086] In step S220, the length ranges of the first metal rod 311 and the second metal rod 312 are calculated. Among them, the distance D1 between the first connecting rod and the corresponding side of the metal outer frame 2 is 0.05 mm - 0.15 mm. The maximum value of the lengths L1 of the first metal rod 311 and the second metal rod 312 is taken, and then the length value L2 of the first connecting rod is selected so that the frequency corresponding to L1 + L2 matches the lower frequency of the two set target operating frequencies; when the match fails, step S210 is re-executed.

[0087] The larger L1 + L2 is, the lower the operating frequency (lower frequency) of the first resonance peak will be. By adjusting L1 + L2, the operating frequency of the first resonance peak is exactly matched with the lower frequency of the two set target operating frequencies. When specifically matching, usually L1 is made as long as possible first, and then L2 is adjusted to match.

[0088] In step S240, the length ranges of the third metal rod 411 and the fourth metal rod 412 are calculated. Among them, the lengths L3 of the third metal rod 411 and the fourth metal rod 412 satisfy L1 ≤ L3 ≤ 1.3 * L1. The maximum value of the lengths L3 of the third metal rod 411 and the fourth metal rod 412 is taken, and then the length value L4 of the second connecting rod is selected so that the frequency corresponding to L3 + L4 matches the higher frequency of the two target operating frequencies. When the match fails, step S210 is re-executed.. The larger L3 + L4 is, the lower the operating frequency (higher frequency) of the second resonance peak will be. By adjusting L3 + L4, the operating frequency of the second resonance peak is exactly matched with the higher frequency of the two set target operating frequencies. When specifically matching, usually L3 is made as long as possible first, and then L4 is adjusted to match.

[0089] Figure 8 and Figure 9 show the transmission spectra of the metasurface system for realizing electromagnetic shielding and transmission window based on mode coupling provided by the present invention at different angles and polarizations, where Figure 8 a linear coordinate is adopted, Figure 9 a logarithmic coordinate is adopted. From Figure 8 it can be seen that near the two target operating frequencies of 8.5 and 17 GHz, the transmittance of the spectrum reaches more than 80%. From Figure 9 it can be seen that within the frequency band of 200 MHz - 33 GHz, the structure has excellent electromagnetic wave shielding performance, and the shielding performance exceeds -20 dB at most frequencies, and the overall average shielding performance reaches -22.5 dB after calculation.

[0090] Obviously, the embodiments described above are only a part of the embodiments of the present invention, rather than all of them. Based on the embodiments of the present invention, those of ordinary skill in the art can make other different forms of changes or modifications without creative efforts, and all of them should fall within the scope of protection of the present invention.

Claims

1. A broadband electromagnetic shielding and wide-angle full polarization double-window high-transmission device based on a mortise and tenon structure metasurface, characterized in that, The broadband electromagnetic shielding and wide-angle full-deflection dual-window high-transmittance device comprises a plurality of structural units periodically arranged along a plane, each structural unit comprising: insulating substrate; A square metal outer frame, the bottom of which is fixed on the insulating substrate and the middle of which is surrounded by a mounting cavity; a first metal structure, the bottom of which is mounted on the insulating substrate and accommodated in the mounting cavity, and is spaced apart from the inner wall of the mounting cavity, the first metal structure comprising a right-angled cross structure and four first connecting rods of equal length, the center of the right-angled cross structure coinciding with the center of the metal outer frame, each end of the right-angled cross structure being perpendicularly connected to a first connecting rod, the first connecting rod being connected to and perpendicular to the corresponding end of the right-angled cross structure at its center, each first connecting rod being parallel to an adjacent side of the metal outer frame, and the four first connecting rods being spaced apart and surrounding a mounting sub-cavity; a second metal structure, the bottom of which is mounted on the insulating substrate and accommodated in the mounting sub-cavity, and is spaced apart from the inner wall of the mounting sub-cavity, the second metal structure comprising an oblique cross structure and four identical right-angle structures, each right-angle structure comprising two second connecting rods of equal length and vertically connected at ends, the oblique cross structure comprising two metal rods of equal length, vertically connected at the center, the center of the oblique cross structure coincides with the center of the metal outer frame and is located on a diagonal of the metal outer frame, and each end of the oblique cross structure is connected to a right-angle structure and is located at the middle of an inner corner of the right-angle structure; The regular cross structure and the oblique cross structure are cross-arranged at the center position through a giving way structure and do not contact each other.

2. The broadband electromagnetic shielding and wide-angle full-deflection double-window high-transmission device based on the mortise and tenon structure metasurface according to claim 1, wherein The regular cross structure includes a first metal rod and a second metal rod of equal length, connected at the center and perpendicular to each other, and the oblique cross structure includes a third metal rod and a fourth metal rod of equal length, connected at the center and perpendicular to each other; Among them, the length of the first metal rod and the second metal rod is L1, the length of the first connecting rod is L2, the length of the third metal rod and the fourth metal rod is L3, and the length of the second connecting rod is L4. The frequency corresponding to L1+L2 matches the low frequency of the two set target operating frequencies, and the frequency corresponding to L3+L4 matches the high frequency of the two set target operating frequencies.

3. The broadband electromagnetic shielding and wide-angle full polarization double-window high-transparency device based on the mortise and tenon structure metasurface according to claim 1, characterized in that, The giving way structure is a first giving way groove structure provided at the center position of the oblique cross structure, or a second giving way groove structure provided at the center position of the regular cross structure.

4. The broadband electromagnetic shielding and wide-angle full-polarization double-window high-transmission device based on the mortise and tenon structure metasurface according to claim 1, wherein, The give-way structure is a first give-way groove structure, and the oblique cross structure includes a third metal rod and a fourth metal rod. A first groove and a second groove of the same length are respectively formed at the center of the third metal rod and the fourth metal rod. The first groove and the second groove are connected together at the center of the metal outer frame to form an installation space; The center of the regular cross structure is accommodated in the installation space and does not contact the inner wall of the installation space.

5. The broadband electromagnetic shielding and wide-angle full polarization double-window high-transmission device based on the mortise and tenon structure metasurface according to claim 4, wherein The depth from the bottom of the first groove to the bottom of the third metal rod and the depth from the bottom of the second groove to the bottom of the fourth metal rod are both D2, where 0.005 mm ≤ D2 ≤ 0.05 mm.

6. The broadband electromagnetic shielding and wide-angle full polarization double-window high-transmission device based on the mortise and tenon structure metasurface according to claim 4, characterized in that, The length of the first groove along the length direction of the third metal rod and the length of the second groove along the length direction of the fourth metal rod are both L5, and L5 is 0.2 mm.

7. The broadband electromagnetic shielding and wide-angle full polarization double-window high-transmission device based on the mortise and tenon structure metasurface according to claim 1, characterized in that, The spacing between each first connecting rod and the wall surface of the side of the adjacent metal outer frame is D1, where 0.05 mm ≤ D1 ≤ 0.15 mm.

8. The broadband electromagnetic shielding and wide-angle full polarization double-window high-transmission device based on the mortise-tenon structure metasurface according to claim 1, characterized in that, The thickness of the insulating substrate is H1, where 1 mm ≤ H1 ≤ 5 mm.

9. The broadband electromagnetic shielding and wide-angle full-deflection double-window high-transmission device based on the mortise-and-tenon structure metasurface according to claim 1, characterized in that, The thickness of the metal outer frame along the length direction is H2, and the width of the metal outer frame is W, where 0.05 mm ≤ H2 ≤ 0.2 mm and 2 mm ≤ W ≤ 6 mm.

10. A parameter configuration method for a broadband electromagnetic shielding and wide-angle full-polarization double-window high-transmission device based on a mortise-tenon structure metasurface, characterized in that, The parameter configuration method for each structural unit includes: Step S210: Select the width of the metal outer frame within a preset range, where the preset range is from 2 mm to 6 mm; Step S220: Calculate the length ranges of the first metal rod and the second metal rod. Among them, the spacing D1 between the first connecting rod and the corresponding side of the metal outer frame is 0.05 mm - 0.15 mm. Take the maximum value of the lengths L1 of the first metal rod and the second metal rod, and then select the value of the length L2 of the first connecting rod so that the frequency corresponding to L1 + L2 matches the lower frequency of the two set target operating frequencies; Step S230: Determine whether the frequency corresponding to L1 + L2 matches the lower frequency of the two set target operating frequencies, and obtain a first judgment result; Step S240: When the first judgment result is yes, calculate the length ranges of the third metal rod and the fourth metal rod. Among them, for the lengths L3 of the third metal rod and the fourth metal rod, L1 ≤ L3 ≤ 1.3 * L1. Take the maximum value of the lengths L3 of the third metal rod and the fourth metal rod, and then select the value of the length L4 of the second connecting rod so that the frequency corresponding to L3 + L4 matches the higher frequency of the two target operating frequencies; otherwise, return to step S210 to reconfigure; Step S250: Determine whether the frequency corresponding to L3 + L4 matches the higher frequency of the two target operating frequencies, and obtain a second judgment result; Step S260: When the second judgment result is yes, the parameter configuration is completed; otherwise, return to step S210 to reconfigure.

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