Broadband electromagnetic shielding and wide-angle full-deviation double-window high-transparency device and parameter configuration method

Abstract

The application discloses a broadband electromagnetic shielding and wide-angle full-deflection double-window high-transparency device and a parameter configuration method. The broadband electromagnetic shielding and wide-angle full-deflection double-window high-transparency device comprises a plurality of structural units arranged periodically 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 formed 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, and the first metal structure is arranged in a spaced manner with the inner wall of the mounting cavity. The first metal structure comprises a positive cross structure and four first connecting rods with equal lengths. The center of the positive cross structure coincides with the center of the metal outer frame. Each end of the positive cross structure is vertically connected with a first connecting rod. The first connecting rod is connected with the end of the corresponding positive cross structure at the center position and is perpendicular.

Description

Technical Field

[0001] This invention relates to the field of electronic technology, and in particular to a broadband electromagnetic shielding and wide-angle fully polarized dual-window high-transmittance device and its parameter configuration method. Background Technology

[0002] The ability to freely control electromagnetic waves has always been a dream and pursuit of humankind. Research on this issue not only has important fundamental scientific significance, but also has significant application value in many fields such as information industry, national defense and security, biomedicine, and energy. However, natural materials are composed of a limited number of types of atoms and structural arrangements, and their electromagnetic response parameters can only take on a very limited range. Therefore, the ability of natural materials to control electromagnetic waves is very limited.

[0003] With the rapid development of modern micro-nano manufacturing technology and materials science, electromagnetic metasurface technology is gradually becoming an important platform for achieving precise control of electromagnetic waves. Electromagnetic metasurfaces are composed of a series of subwavelength artificial atoms arranged in a specific two-dimensional macroscopic sequence. By precisely designing the microstructure at the subwavelength scale, effective control over the amplitude, phase, and polarization state of incident electromagnetic waves can be achieved locally. Among these applications, the ability of electromagnetic metasurfaces to control electromagnetic wave shielding and windowing properties shows broad application prospects in fields such as wireless communication and radar stealth.

[0004] Currently, traditional radar stealth technology mainly employs the fabrication of a metal mesh structure composed of highly conductive metals on the surface of materials, primarily targeting the centimeter wave band of 2-18 GHz. In recent years, with the vigorous development and advancement of anti-stealth technology, the demand for radar stealth performance is shifting towards "ultra-wideband" and "high-efficiency." Simultaneously, to cope with complex real-world application scenarios and facilitate integration with other devices, achieving broadband and efficient stealth often requires ensuring normal high electromagnetic wave transmission within specific frequency windows.

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

[0006] The above content is only used to help understand 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 this invention is to provide a broadband electromagnetic shielding and wide-angle fully polarized dual-window high-transmittance device and parameter configuration method, which aims to solve the technical problem that traditional metasurface devices in the prior art usually achieve specific functions within a single operating frequency band and cannot ensure normal high transmission of electromagnetic waves at multiple specific frequency windows.

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

[0009] Insulating substrate;

[0010] A square metal frame is fixed at the bottom to the insulating substrate and has a mounting cavity formed in the middle.

[0011] A first metal structure is mounted on the insulating substrate and housed within the mounting cavity, and is spaced apart from the inner wall of the mounting cavity. The first metal structure includes a cross structure and four first connecting rods of equal length. The center of the cross structure coincides with the center of the metal frame. Each end of the cross structure is vertically connected to a first connecting rod. The first connecting rod is connected to the corresponding end of the cross structure at its center position and is perpendicular to it. Each first connecting rod is parallel to the adjacent edge of the metal frame. The four first connecting rods are spaced apart and surround a mounting sub-cavity.

[0012] The second metal structure is mounted on the insulating substrate and housed within the mounting cavity, and is spaced apart from the inner wall of the mounting cavity. The second metal structure includes a diagonal cross structure and four identical right-angle structures. Each right-angle structure includes two second connecting rods of equal length that are perpendicularly connected at their ends. The diagonal cross structure includes two metal rods of equal length that are perpendicularly connected at their center. The center of the diagonal cross structure coincides with the center of the metal outer frame and is located on the diagonal of the metal outer frame. Each end of the diagonal cross structure is connected to a right-angle structure located at the middle position of the inner angle of the right-angle structure.

[0013] The symmetrical cross structure and the oblique cross structure are arranged in an intersecting manner at the center position through a clearance structure, and do not contact each other.

[0014] Preferably, in the broadband electromagnetic shielding and wide-angle fully polarized dual-window high-transmittance device based on the mortise and tenon structure metasurface, the positive 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] The lengths of the first and second metal rods are L1, the length of the first connecting rod is L2, the lengths of the third and fourth metal rods are 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 fully polarized dual-window high-transmittance device based on the mortise and tenon structure metasurface, the clearance structure is a first clearance groove structure located at the center of the oblique cross structure, or a second clearance groove structure located at the center of the upright cross structure.

[0017] Preferably, in the broadband electromagnetic shielding and wide-angle fully polarized dual-window high-transmittance device based on the mortise and tenon structure metasurface, the clearance structure is a first clearance groove structure, and the oblique cross structure includes a third metal rod and a fourth metal rod. 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. 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 cross structure is housed within the installation space and does not contact the inner wall of the installation space.

[0019] Preferably, in the broadband electromagnetic shielding and wide-angle fully polarized dual-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 fully polarized dual-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 0.2mm.

[0021] Preferably, in the broadband electromagnetic shielding and wide-angle fully polarized dual-window high-transparency device based on the mortise and tenon structure metasurface, the distance between each first connecting rod and the wall surface of its nearest metal frame edge is D1, 0.05mm≤D1≤0.15mm.

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

[0023] Preferably, in the broadband electromagnetic shielding and wide-angle fully polarized dual-window high-transparency device based on the mortise and tenon structure metasurface, the thickness of the metal frame along the length direction is H2, and the width of the metal frame is W, 0.05mm≤H2≤0.2mm, 2mm≤W≤6mm.

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

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

[0026] Step S220: Calculate the length range of the first metal rod and the second metal rod, wherein the distance D1 between the first connecting rod and the corresponding metal frame edge is 0.05mm-0.15mm. Take the maximum value of the length L1 of the first metal rod and the second metal rod, and then select the length L2 value of the first connecting rod so that the frequency corresponding to L1+L2 matches the low frequency of the two set target working frequencies.

[0027] Step S230: Determine whether the frequency corresponding to L1+L2 matches the low frequency of the two set target operating frequencies to obtain the first judgment result;

[0028] Step S240: If the first judgment result is yes, calculate the length range of the third metal rod and the fourth metal rod, where the length L3 of the third metal rod and the fourth metal rod is L1≤L3≤1.3*L1. Take the maximum value of the length L3 of the third metal rod and the fourth metal rod, and then select the length L4 of the second connecting rod so that the frequency corresponding to L3+L4 matches the high frequency of the two target working frequencies; otherwise, return to step S210 to reconfigure.

[0029] Step S250: Determine whether the frequency corresponding to L3+L4 matches the high frequency of the two target operating frequencies to obtain the second judgment result;

[0030] In step S260, if the second judgment result is yes, the parameter configuration is complete; otherwise, return to step S210 to reconfigure.

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

[0032] This invention provides a broadband electromagnetic shielding and wide-angle fully polarized dual-window high-transmittance device based on a metasurface with a mortise and tenon structure. The device comprises multiple structural units arranged periodically along a plane. Each structural unit includes an insulating substrate, a square metal frame, and a first metal structure. The bottom of the metal frame is fixed to 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 within the mounting cavity, spaced apart from the inner wall of the cavity. The first metal structure includes a symmetrical cross structure and four first connecting rods of equal length. The center of the symmetrical cross structure coincides with the center of the metal frame. Each end of the symmetrical cross structure is vertically connected to a first connecting rod. The first connecting rod is connected perpendicularly to the corresponding end of the symmetrical cross structure at its center. Each first connecting rod is parallel to the adjacent edge of the metal frame. The four first connecting rods are spaced apart and form a [missing information - likely a shape or structure]. The device comprises a mounting cavity; the bottom of a second metal structure is mounted on the insulating substrate and housed within the mounting cavity, spaced apart from the inner wall of the mounting cavity. The second metal structure includes a diagonal cross structure and four identical right-angle structures. Each right-angle structure includes two second connecting rods of equal length connected perpendicularly at their ends. The diagonal cross structure includes two metal rods of equal length connected perpendicularly at their center. The center of the diagonal cross structure coincides with the center of the metal outer frame and is located on the diagonal of the metal outer frame. Each end of the diagonal cross structure is connected to a right-angle structure located at the midpoint of the inner angle of the right-angle structure. The diagonal cross structure and the right-angle cross structure are arranged intersecting at their center through a clearance structure, without contacting each other. This allows for broadband shielding from 200MHz to 33GHz using an electromagnetic metasurface, while simultaneously opening two windows at specific frequency points, providing stable high transmittance performance for different incident angles and polarizations. Compared to previous metasurface devices, the design proposed in this invention offers advantages such as wide bandwidth, dual windows, large angle, and full polarization.

[0033] Furthermore, the metal frame, the first metal structure, and the second metal structure are not in contact with each other. In this way, the resonant structure uses the oscillation of induced current inside the metal structure to store energy. If the first and second metal structures inside are in contact with the outer metal frame, the induced current on the first and second metal structures will carry energy to the outer metal frame, causing the resonant mode to fail to be excited. If the first and second metal structures inside are in contact with each other, the induced current on the first and second metal structures will interfere with each other when the resonant mode is excited, triggering additional resonant modes and reducing device performance.

[0034] Furthermore, the metal frame, the first metal structure, and the second metal structure should all adopt a structure with four-dimensional symmetry to ensure the overall four-dimensional symmetry of the metasurface device. Taking the metasurface plane as the xoy plane, any incident wave in space can be decomposed into a superposition of incident waves with wave vectors located in the xoz and yoz planes. When the metasurface has four-dimensional symmetry, since the incident conditions in the xoz and yoz planes are exactly the same, the designed metasurface can maintain stable shielding and high transmission performance for both TE and TM polarizations incident with wave vectors located in the xoz plane, meaning it can maintain stable shielding and high transmission performance for incident waves throughout space.

[0035] Furthermore, traditional radar stealth structures often only have the ability to shield electromagnetic waves, and the shielding bandwidth is limited. This invention, while optimizing the metal frame to achieve wider electromagnetic shielding, incorporates a tenon-and-mortise type metal resonant structure (a first metal structure and a second metal structure) into the structure to achieve high transmittance in two specific frequency windows; moreover, the device performance features large angle and full polarization characteristics, maintaining good performance against incident waves from all directions in practical application scenarios. Attached Figure Description

[0036] Figure 1 A schematic diagram of an embodiment of the broadband electromagnetic shielding and wide-angle fully polarized dual-window high-transmittance device provided by the present invention;

[0037] Figure 2 for Figure 1 A schematic diagram of each structural unit;

[0038] Figure 3 for Figure 2 Cross-sectional view from a single perspective;

[0039] Figure 4 for Figure 3 A partial schematic diagram of the first metal structure in the middle;

[0040] Figure 5 for Figure 3 A partial schematic diagram of the second metal structure in the middle;

[0041] Figure 6 for Figure 5 A diagram from another perspective;

[0042] Figure 7 A flowchart illustrating the method for determining the parameters of each structural unit in the metasurface system that achieves electromagnetic shielding and transmission windows based on mode coupling, as provided in this invention.

[0043] Figure 8 The transmission spectra of the metasurface system for electromagnetic shielding and transmission window based on mode coupling provided by the present invention are shown at different angles and polarizations, with the vertical axis using linear coordinates.

[0044] Figure 9 The transmission spectra of the metasurface system based on mode coupling to achieve electromagnetic shielding and transmission window provided by this invention are shown at different angles and polarizations, with the ordinate on a logarithmic scale.

[0045] 1000-Broadband electromagnetic shielding and wide-angle fully polarized dual-window high-transmittance device, 100-Structural unit, 1-Insulating substrate, 2-Metal frame, 21-First frame member, 22-Second frame member, 23-Third frame member, 24-Fourth frame member, 3-First metal structure, 31-True 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- The structure is a diagonal cross, with 411-third metal bar, 4111-first slot, 412-fourth metal bar, 4121-second slot, 421-first right-angle structure, 4211-fifth bar, 4212-sixth bar, 422-second right-angle structure, 4221-seventh bar, 4222-eighth bar, 423-third right-angle structure, 4231-ninth bar, 4232-tenth bar, 424-fourth right-angle structure, 4241-eleventh bar, and 4242-twelfth bar.

[0046] The objectives, features, and advantages of this invention will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0047] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. The present invention will be described in detail below with reference to the accompanying drawings and embodiments. It should be noted that, unless otherwise specified, the embodiments and features in the embodiments of the present invention can be combined with each other.

[0048] In this embodiment of the invention, the term "and / or" describes the relationship between associated objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. The character " / " generally indicates that the preceding and following associated objects have an "or" relationship.

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

[0050] In this embodiment of the invention, the term "multiple" refers to two or more, and other quantifiers are similar.

[0051] In this invention, unless otherwise stated, directional terms such as "upper," "lower," "top," and "bottom" are generally used in relation to the direction shown in the accompanying drawings, or in relation to the vertical, perpendicular, or gravitational direction of the component itself; similarly, for ease of understanding and description, "inner" and "outer" refer to the inner and outer contours of each component itself, but the above directional terms are not intended to limit this invention.

[0052] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the various embodiments of the present invention will be described in detail below with reference to the accompanying drawings. However, those skilled in the art will understand that many technical details are presented in the embodiments of the present invention to facilitate a better understanding of the invention. However, the technical solutions claimed in the present invention can be implemented even without these technical details and various variations and modifications based on the following embodiments. The division of the following embodiments is for ease of description and should not constitute any limitation on the specific implementation of the present invention. The various embodiments can be combined with and referenced by each other without contradiction.

[0053] To resolve the above issues, please refer to Figure 1 This invention provides a broadband electromagnetic shielding and wide-angle fully polarized dual-window high-transmittance device 1000 based on a mortise and tenon structure metasurface. This device comprises multiple structural units arranged periodically along a plane. (See also...) Figure 2 and Figure 3 Each structural unit 100 includes an insulating substrate 1, a square metal 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 fully polarized dual-window high-transmittance device 1000 based on a mortise and tenon structure metasurface includes multiple structural units 100 arranged periodically along the plane. These units can be hundreds or even thousands of structural units 100 arranged periodically along the x and y directions, without specific limitations. In this embodiment, the broadband electromagnetic shielding and wide-angle fully polarized dual-window high-transmittance device 1000 includes 137*137 structural units 100 arranged along 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 frame 2, the first metal structure 3, and the second metal structure 4. The metal frame 2, the first metal structure 3, and the second metal structure 4 can be embedded in the surface of the insulating substrate 1. In some embodiments, the insulating substrate 1 can be a dielectric substrate with a relative permittivity of 3.3 and a thickness of 4.4 mm. In other embodiments, the insulating substrate 1 can be any insulating material.

[0056] The insulating substrate 1 causes the FP effect, which induces additional resonant modes. The FP effect means that when an electromagnetic wave is incident on an insulating substrate 1 of a certain thickness, there are not only two transmission and reflection events, but also multiple transmission and reflection events at the upper and lower interfaces of the insulating substrate 1. The final reflected and transmitted signals in the air on both sides are the interference superposition of this series of signals.

[0057] When the resonant frequency of the FP resonant mode is close to the resonant frequency of the target's tenon-and-mortise metal resonant structure, it severely interferes with the original high transmittance performance. Therefore, it is necessary to adjust the thickness of the insulating substrate 1 to reduce the impact of the FP effect. The thicker the insulating substrate 1, the lower the frequency of the FP resonant mode; conversely, the thinner the insulating substrate 1, the higher the frequency of the FP resonant mode. Therefore, the thickness of the insulating substrate 1 can be adjusted according to the two target operating frequencies, avoiding both excessive thickness and insufficient thickness. In some embodiments, the thickness of the insulating substrate 1 is H1, where 1 mm ≤ H1 ≤ 5 mm. In other embodiments, the thickness of the insulating substrate 1 can be adjusted according to the actual frequency position of the target window.

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

[0059] The mesh size formed by the metal frame 2 should be much smaller than the wavelength. Since the first metal structure 3 and the second metal structure 4 are placed inside the metal frame 2, and the typically studied wavelength range is 200 MHz-33 GHz, the thickness of the metal frame 2 along its length is H2, where 0.05 mm ≤ H2 ≤ 0.2 mm. Therefore, the width W of the metal frame 2 cannot be arbitrarily small. If the width W is too small, high-frequency electromagnetic waves will penetrate the metal frame 2 more easily; if the width W is too large, it will affect the shielding performance, with a larger width W resulting in poorer shielding performance. Therefore, when the width W of the metal frame 2 cannot be further reduced, it is necessary to appropriately increase the width W. Thus, in some embodiments, the width W of the metal frame 2 is typically chosen to be between 2 mm and 6 mm.

[0060] The bottom of the metal frame 2 is fixed to the insulating substrate 1, and a mounting cavity is formed in the middle. The mounting cavity is used to install 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, which can be arranged periodically along the x and y directions. Multiple metal frames 2 are arranged at intervals p along the width and length directions, so that multiple 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 and the thickness H2 of the metal frame 2 along the length direction. The metal 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 connected together in sequence to form a square. The dimensions of the first frame member 21 to the fourth frame member 24 are all the same.

[0061] The metal frame 2 provides a broadband shielding background with a negative dielectric constant, while the first metal structure 3 and the second metal structure 4 provide a positive dielectric constant response resonance at a specific frequency. When the two structures are superimposed, the overall dielectric constant of the synthesized structure will be close to that of air at a specific frequency, at which point impedance matching is achieved and electromagnetic high-transmission effect is realized.

[0062] Please see Figure 3 and Figure 4 The bottom of the first metal structure 3 is mounted on the insulating substrate 1 and housed within the mounting cavity, and is spaced apart from the inner wall of the mounting cavity. The first metal structure 3 includes a cross structure 31 and four first connecting rods of equal length. The center of the cross structure 31 coincides with the center of the metal outer frame 2. Each end of the cross structure 31 is vertically connected to a first connecting rod. The first connecting rod is connected to the corresponding end of the cross structure 31 at its center position and is perpendicular to it. Each first connecting rod is parallel to the adjacent edge of the metal outer frame 2. The four first connecting rods are spaced apart and surround a mounting sub-cavity.

[0063] It is worth noting that the first metal structure 3 is spaced apart from the inner wall of the mounting cavity, which means that each component of the first metal structure 3 does not contact the metal outer frame 2. Neither the cross structure 31 nor the four first connecting rods contact the metal outer frame 2.

[0064] The cross structure 31 includes a first metal rod 311 and a second metal rod 312 of equal length, connected at the center and perpendicular to each other. The first metal rod 311 and the second metal rod 312 are intersected and connected at the center. In some embodiments, the first metal rod 311 and the second metal rod 312 may be integrally formed; in other embodiments, the first metal rod 311 and the second metal rod 312 may be independently formed and intersected at the center.

[0065] The first metal rod 311 is perpendicular to two opposite sides of the metal outer frame 2 and is located in the middle. The second metal rod 312 is perpendicular to the other two opposite sides of the metal outer frame 2 and is located in the middle. For example, the first metal rod 311 is perpendicular to the first frame member 21 and the third frame member 23 and is located in the middle, and the second metal rod 312 is perpendicular to the second frame member 22 and the fourth frame member 24 and is located in the middle. 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 designated as first rod 321, second rod 322, third rod 323, and fourth rod 324. The two ends of the first metal rod 311 are perpendicularly connected to the first rod 321 and the third rod 323, respectively, with the first rod 321 and the third rod 323 connected to the first metal rod 311 at their respective midpoints. The two ends of the second metal rod 312 are perpendicularly connected to the second rod 322 and the fourth rod 324, respectively, with the second rod 322 and the fourth rod 324 connected to the second metal rod 312 at their respective midpoints. When the first metal rod 311 is perpendicular to the first frame member 21 and the third frame member 23 and located in their middle position, and the second metal rod 312 is perpendicular to the second frame member 22 and the fourth frame member 24 and located in their middle position, the first rod 321 and the third rod 323 are parallel to the first frame member 21 and the third frame member 23, respectively, and the second rod 322 and the fourth rod 324 are parallel to the second frame member 22 and the fourth frame member 24, respectively. The first rod 321 is not in contact with the first frame member 21, the second rod 322 is not in contact with the second frame member 22, the third rod 323 is not in contact with the third frame member 23, and the fourth rod 324 is not in contact with the fourth frame member 24.

[0067] It is worth noting that the two adjacent poles 321, 322, 323, and 324 do not make contact.

[0068] The first metal structure 3 and the second metal structure 4 correspond to the frequencies of the high-transmittance windows in the operating frequencies, respectively. The first metal structure 3 corresponds to the lower 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, the longer the resonant wavelength and the lower the resonant frequency, the position of the lower operating frequency can be adjusted by changing 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 its nearest neighboring metal frame 2 is D1. If D1 is too large, it will restrict the lengths of the first metal rod 311, the second metal rod 312, and the first connecting rod from being too small; however, each first connecting rod cannot contact the wall surface of its nearest neighboring metal frame 2, so D1 cannot be too small to avoid poor control and potential contact. In some embodiments, 0.05mm ≤ D1 ≤ 0.15mm.

[0069] In some embodiments, the first metal rod 311, the second metal rod 312, and the first connecting rod are made of copper; in other embodiments, the first metal rod 311, the second metal rod 312, and the first connecting rod may be made of other metals, depending on specific needs.

[0070] The first metal structure 3 opens the first target transmission window at a specific frequency, achieving high transmittance. This is mainly because the resonant structure excites local resonance at a specific frequency, causing the induced current to oscillate back and forth inside the first metal structure 3, thus locally storing the input electromagnetic energy. When the frequency of the external electromagnetic wave matches the resonant frequency, the energy carried by the incident wave can couple into the structure and be transferred to the other side of the shield through the resonant mode, thereby achieving high transmittance.

[0071] Please see Figure 3 , Figure 5 and Figure 6 The bottom of the second metal structure 4 is mounted on the insulating substrate 1 and housed within the mounting cavity, and is spaced apart from the inner wall of the mounting cavity. The second metal structure 4 includes a diagonal cross structure 41 and four identical right-angle structures. Each right-angle structure includes two second connecting rods of equal length that are vertically connected at their ends. The diagonal cross structure 41 includes two metal rods of equal length that are vertically connected together at their center. The center of the diagonal 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. Each end of the diagonal 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 is worth noting that the second metal structure 4 is spaced apart from the inner wall of the mounting cavity, meaning that each component of the second metal structure 4 does not contact any component of the first metal structure 3. Neither the first metal rod 311 nor the second metal rod 312, nor the four second connecting rods, come into contact with the second metal structure 4.

[0073] The oblique cross structure 41 includes a third metal rod 411 and a fourth metal rod 412 of equal length, connected at the center and perpendicular to each other. The third metal rod 411 and the fourth metal rod 412 are intersected and connected together at the center. In some embodiments, the third metal rod 411 and the fourth metal rod 412 may be integrally formed; in other embodiments, the third metal rod 411 and the fourth metal rod 412 may be independently formed and intersected and 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. This can be understood as the center of the third metal rod 411 coinciding with the center of the metal outer frame 2 and located on one diagonal of the metal outer frame 2, and the center of the fourth metal rod 412 coinciding with the center of the metal outer frame 2 and located on the other diagonal of the metal outer frame 2.

[0075] The four right-angle structures are designated as the first right-angle structure 421, the second right-angle structure 422, the third right-angle structure 423, and the fourth right-angle structure 424. The first right-angle structure 421 includes the fifth rod 4211 and the sixth rod 4212; the second right-angle structure 422 includes the seventh rod 4221 and the eighth rod 4222; the third right-angle structure 423 includes the ninth rod 4231 and the tenth rod 4232; and the fourth right-angle structure 424 includes the eleventh rod 4241 and the twelfth rod 4242. 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 located on both sides of the third metal rod 411, and the angle between the fifth rod 4211 and the sixth rod 4212 and the third metal rod 411 is 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 located on both sides of the third metal rod 411, and the angle between the ninth rod 4231 and the tenth rod 4232 and the third metal rod 411 is 45 degrees. One end of each of the fifth rod 4211 and the sixth rod 4212, and the ninth rod 4231 and the tenth rod 4232 are connected to the third metal rod 411, and the other ends extend inward.

[0077] One end of the fourth metal rod 412 is connected to the seventh rod 4221 and the eighth rod 4222. The seventh rod 4221 and the eighth rod 4222 are located on both sides of the fourth metal rod 412, and the angle between the seventh rod 4221 and the eighth rod 4222 and the fourth metal rod 412 is 45 degrees. The other end of the fourth metal rod 412 is connected to the eleventh rod 4241 and the twelfth rod 4242. The eleventh rod 4241 and the twelfth rod 4242 are located on both sides of the fourth metal rod 412, and the angle between the eleventh rod 4241 and the twelfth rod 4242 and the fourth metal rod 412 is 45 degrees. The seventh rod 4221 and the eighth rod 4222, and 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 it achieves high transmission is similar 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 upright cross structure 31 and the oblique cross structure 41 are arranged in a cross configuration at their center positions through a clearance structure, and do not contact each other.

[0079] In some embodiments, the clearance structure is a first clearance groove structure located at the center of the oblique cross structure 41, and the center of the symmetrical cross structure 31 is accommodated in the first clearance groove structure without contacting the wall of the first clearance groove structure; in other embodiments, the clearance structure may also be a second clearance groove structure located at the center of the symmetrical cross structure 31, and the center of the oblique cross structure 41 is accommodated in the second clearance groove structure without contacting the inner wall of the second clearance groove structure.

[0080] The following description uses a first clearance groove structure located at the center of the oblique cross structure 41 as an example. The third metal rod 411 and the fourth metal rod 412 each have a first groove 4111 and a second groove 4121 of the same length at their center positions. 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 symmetrical cross structure 31 is accommodated within the installation space and does not contact the inner wall of the installation space. It is important to emphasize that the first groove 4111 does not penetrate the third metal rod 411, and the second groove 4121 does not penetrate 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 remaining depth 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 remaining depth after the fourth metal rod 412 is removed. In some embodiments, D2 is 0.005mm-0.05mm.

[0081] The length of the first groove 4111 along the length direction of the third metal rod 411 is L5, and the length of the second groove 4121 along the length direction of the fourth metal rod 412 is also L5. L5 needs to 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 L5 is too large, it will cause a decrease in the intensity of the resonance peak at the operating frequency corresponding to the oblique cross structure 41, and a decrease in the transmittance of the corresponding resonance peak. In some embodiments, L5 is 0.2 mm.

[0082] The metal frame 2, the first metal structure 3, and the second metal structure 4 are not in contact with each other. In this resonant structure, energy is stored by the oscillation of induced current inside the metal structure. If the first metal structure 3 and the second metal structure 4 inside are in contact with the outer metal frame 2, the induced current on the first metal structure 3 and the second metal structure 4 will carry energy to the outer metal frame 2, causing the resonant mode to fail to be excited. If the first metal structure 3 and the second metal structure 4 inside are in contact with each other, the induced current on the first metal structure 3 and the second metal structure 4 will interfere with each other when the resonant mode is excited, triggering additional resonant modes and reducing device performance.

[0083] Furthermore, the metal frame 2, the first metal structure 3, and the second metal structure 4 should all adopt structures with four-dimensional symmetry to ensure the overall four-dimensional symmetry of the metasurface device. Taking the metasurface plane as the xoy plane, any incident wave in any direction in space can be decomposed into a superposition of incident waves with wave vectors located in the xoz and yoz planes. When the metasurface has four-dimensional symmetry, since the incident conditions in the xoz and yoz planes are exactly the same, the designed metasurface can maintain stable shielding and high transmission performance for both TE and TM polarizations incident with wave vectors located in the xoz plane, meaning it can maintain stable shielding and high transmission performance for incident waves throughout space.

[0084] This invention also provides a parameter configuration method for a broadband electromagnetic shielding and wide-angle, fully polarized, dual-window high-transmittance device based on a mortise and tenon structure metasurface. Figure 7 This diagram illustrates one embodiment of the parameter configuration method for a broadband electromagnetic shielding and wide-angle, fully polarized dual-window high-transmittance device based on a mortise-and-tenon structure metasurface according to the present invention. Please refer to... Figure 7 The parameter configuration method for each structural unit in the broadband electromagnetic shielding and wide-angle fully polarized dual-window high-transmittance device based on the mortise and tenon structure metasurface can be directly referred to the parameter configuration method for each structural unit.

[0085] In step S210, the width of the metal frame 2 is selected within a preset range, where the preset range is 2mm to 6mm. First, a width of the metal frame 2 is selected within the preset range. This can be a random selection or a selection based on certain rules, such as selecting from large to small or from small to large at certain intervals.

[0086] In step S220, the length range of the first metal rod 311 and the second metal rod 312 is calculated. The distance D1 between the first connecting rod and the corresponding edge of the metal outer frame 2 is 0.05mm-0.15mm. The maximum value of the length L1 of the first metal rod 311 and the second metal rod 312 is taken, and then the length L2 value of the first connecting rod is selected so that the frequency corresponding to L1+L2 matches the low frequency of the two set target working frequencies. If a match cannot be found, step S210 is executed again.

[0087] The larger L1+L2 is, the lower the operating frequency (low frequency) of the first resonant peak will be. By adjusting L1+L2, the operating frequency of the first resonant peak can be matched precisely with the low frequency of the two set target operating frequencies. In specific matching, it is usually best to make L1 as long as possible first, and then adjust L2 to achieve the matching.

[0088] In step S240, the length range of the third metal rod 411 and the fourth metal rod 412 is calculated. The length L3 of the third metal rod 411 and the fourth metal rod 412 is L1≤L3≤1.3*L1. The maximum value of L3 for both the third metal rod 411 and the fourth metal rod 412 is taken. Then, the length L4 of the second connecting rod is selected, so that the frequency corresponding to L3+L4 matches the high-frequency of the two target operating frequencies. If a match cannot be achieved, step S210 is repeated. The larger L3+L4 is, the lower the operating frequency (high frequency) of the second resonance peak will be. By adjusting L3+L4, the operating frequency of the second resonance peak is made to match the high-frequency of the two set target operating frequencies. In specific matching, it is usually best to make L3 as long as possible first, and then adjust L4 to achieve the match.

[0089] Figure 8 and Figure 9 The diagram illustrates the transmission spectra of the metasurface system based on mode coupling for electromagnetic shielding and transmission windows provided by this invention at different angles and polarizations, wherein... Figure 8 Linear coordinates were used. Figure 9 Logarithmic coordinates were used. Figure 8 It can be seen that the transmittance of the spectral lines reaches over 80% near the operating frequencies of the two targets, 8.5 GHz and 17 GHz. Figure 9 It can be seen that the structure has excellent shielding performance against electromagnetic waves in the 200MHz-33GHz band, with shielding performance exceeding -20dB at most frequencies, and the overall average shielding performance is calculated to reach -22.5dB.

[0090] Obviously, the embodiments described above are merely some, not all, embodiments of the present invention. Based on the embodiments of the present invention, those skilled in the art can make other variations or modifications without creative effort, and all such variations or modifications should fall within the scope of protection of the present invention.

Claims

1. A broadband electromagnetic shielding and wide-angle, fully polarized dual-window high-transmittance device based on a metasurface with a mortise and tenon structure, characterized in that, The broadband electromagnetic shielding and wide-angle fully polarized dual-window high-transmittance device comprises multiple structural units arranged periodically along a plane, each structural unit comprising: Insulating substrate; A square metal frame is fixed at the bottom to the insulating substrate and has a mounting cavity formed in the middle. A first metal structure is mounted on the insulating substrate and housed within the mounting cavity, and is spaced apart from the inner wall of the mounting cavity. The first metal structure includes a cross structure and four first connecting rods of equal length. The center of the cross structure coincides with the center of the metal frame. Each end of the cross structure is vertically connected to a first connecting rod. The first connecting rod is connected to the corresponding end of the cross structure at its center position and is perpendicular to it. Each first connecting rod is parallel to the adjacent edge of the metal frame. The four first connecting rods are spaced apart and surround a mounting sub-cavity. The second metal structure is mounted on the insulating substrate and housed within the mounting cavity, and is spaced apart from the inner wall of the mounting cavity. The second metal structure includes a diagonal cross structure and four identical right-angle structures. Each right-angle structure includes two second connecting rods of equal length that are perpendicularly connected at their ends. The diagonal cross structure includes two metal rods of equal length that are perpendicularly connected at their center. The center of the diagonal cross structure coincides with the center of the metal outer frame and is located on the diagonal of the metal outer frame. Each end of the diagonal cross structure is connected to a right-angle structure located at the middle position of the inner angle of the right-angle structure. The symmetrical cross structure and the oblique cross structure are arranged in an intersecting manner at the center position through a clearance structure, and do not contact each other.

2. The broadband electromagnetic shielding and wide-angle fully polarized dual-window high-transmittance device based on a mortise and tenon structure metasurface as described in claim 1, characterized in that, The upright 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. The lengths of the first and second metal rods are L1, the length of the first connecting rod is L2, the lengths of the third and fourth metal rods are 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 fully polarized dual-window high-transmittance device based on a mortise and tenon structure metasurface as described in claim 1, characterized in that, The clearance structure is either a first clearance groove structure located at the center of the oblique cross structure, or a second clearance groove structure located at the center of the upright cross structure.

4. The broadband electromagnetic shielding and wide-angle fully polarized dual-window high-transmittance device based on a mortise and tenon structure metasurface as described in claim 1, characterized in that, The clearance structure is a first clearance groove structure. The oblique cross structure includes a third metal rod and a fourth metal rod. 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. 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 cross structure is housed within the installation space and does not contact the inner wall of the installation space.

5. The broadband electromagnetic shielding and wide-angle fully polarized dual-window high-transmittance device based on a mortise and tenon structure metasurface as described in claim 4, characterized in that, 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 0.005mm≤D2≤0.05mm.

6. The broadband electromagnetic shielding and wide-angle fully polarized dual-window high-transmittance device based on a mortise and tenon structure metasurface as described in claim 4, characterized in that, The length of the first groove along the length of the third metal rod and the length of the second groove along the length of the fourth metal rod are both L5, where L5 is 0.2 mm.

7. The broadband electromagnetic shielding and wide-angle fully polarized dual-window high-transmittance device based on a mortise and tenon structure metasurface as described in claim 1, characterized in that, The distance between each first connecting rod and the wall surface of its nearest metal frame edge is D1, 0.05mm≤D1≤0.15mm.

8. The broadband electromagnetic shielding and wide-angle fully polarized dual-window high-transmittance device based on a mortise and tenon structure metasurface as described in claim 1, characterized in that, The thickness of the insulating substrate is H1, where 1mm ≤ H1 ≤ 5mm.

9. The broadband electromagnetic shielding and wide-angle fully polarized dual-window high-transmittance device based on a mortise and tenon structure metasurface as described in claim 1, characterized in that, The thickness of the metal frame along its length is H2, and the width of the metal frame is W, where 0.05mm≤H2≤0.2mm and 2mm≤W≤6mm.

10. A parameter configuration method for a broadband electromagnetic shielding and wide-angle fully polarized dual-window high-transmittance device based on a metasurface with a mortise and tenon structure as described in any one of claims 1 to 9, characterized in that, The parameter configuration methods for each structural unit include: Step S210: Take the width of the metal frame within a preset range, where the preset range is 2mm to 6mm; Step S220: Calculate the length range of the first metal rod and the second metal rod, wherein the distance D1 between the first connecting rod and the corresponding metal frame edge is 0.05mm-0.15mm. Take the maximum value of the length L1 of the first metal rod and the second metal rod, and then select the length L2 value of the first connecting rod so that the frequency corresponding to L1+L2 matches the low frequency of the two set target working frequencies. Step S230: Determine whether the frequency corresponding to L1+L2 matches the low frequency of the two set target operating frequencies to obtain the first judgment result; Step S240: If the first judgment result is yes, calculate the length range of the third metal rod and the fourth metal rod, where the length L3 of the third metal rod and the fourth metal rod is L1≤L3≤1.3*L1. Take the maximum value of the length L3 of the third metal rod and the fourth metal rod, and then select the length L4 of the second connecting rod so that the frequency corresponding to L3+L4 matches the high frequency of the two target working frequencies; otherwise, return to step S210 to reconfigure. Step S250: Determine whether the frequency corresponding to L3+L4 matches the high frequency of the two target operating frequencies to obtain the second determination result; In step S260, if the second judgment result is yes, the parameter configuration is complete; otherwise, return to step S210 to reconfigure.

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