Frequency selective surface unit with wide angle stability

Abstract

The invention provides a frequency selective surface unit with large-angle stability, the frequency selective surface unit comprises a dielectric layer, a first metal layer and a second metal layer, the dielectric layer is provided with a mounting part, and the mounting part is used for enabling two frequency selective surface units to be connected in a cross manner; the first metal layer is arranged on one side of the dielectric layer; the second metal layer is arranged on the side, away from the first metal layer, of the dielectric layer, and a capacitive structure or device is arranged on the second metal layer. According to the frequency selective surface device, the first metal layer can generate the electric response, and the second metal layer can generate the magnetic response, so that electromagnetic regulation and control can be performed on the frequency selective surface device with the crossed frequency selective surface units; the frequency selective surface device with the three-dimensional structure can have high selectivity of high wave transmission in the first working frequency band with relatively high frequency and high reflection in the second working frequency band with relatively low frequency, loss is low, and dual-polarization wide-angle stability is achieved at the same time.

Description

Technical Field

[0001] The present application relates to the field of communication technology, and in particular to a frequency selective surface unit with large angular stability. Background Art

[0002] Frequency Selective Surface (FSS) can artificially control the transmittance and reflectivity of electromagnetic waves according to the incident frequency of electromagnetic waves. However, in actual engineering application scenarios, the control effect of frequency selective surfaces on electromagnetic waves is weakened due to factors such as the incident angle and working bandwidth. Among them, the most typical problem is that it is difficult to achieve large-angle stability of frequency selective surfaces in a wider frequency band. Summary of the invention

[0003] The purpose of the present application is to provide a frequency selective surface unit, a frequency selective surface device, an antenna system and a communication device, so that the frequency selective surface can achieve large angle stability of the frequency selective surface in a wider frequency band.

[0004] The first aspect of the present application provides a frequency selective surface unit, which includes a dielectric layer, a first metal layer and a second metal layer, the dielectric layer is provided with a mounting portion, and the mounting portion is used to cross-connect two of the frequency selective surface units; the first metal layer is arranged on one side of the dielectric layer; the second metal layer is arranged on a side of the dielectric layer away from the first metal layer, and a capacitive structure or device is arranged on the second metal layer.

[0005] In the present application, the first metal layer can generate an electrical response, and the second metal layer can generate a magnetic response, so that the equivalent dielectric constant and the magnetic permeability of the cross-arranged first frequency selective surface unit and the second frequency selective surface unit can be regulated, so that the frequency selective surface device with a three-dimensional structure can have high wave transmittance in the second working frequency band with a relatively high frequency, high reflectivity and high selectivity in the second working frequency band with a relatively low frequency, and low loss, while achieving dual-polarization large-angle stability.

[0006] In a possible design, along the first direction of the dielectric layer, at least one side edge of the dielectric layer is provided with a notch, along the second direction of the dielectric layer, one end of the notch passes through one side edge of the dielectric layer, and the other end of the notch forms a step surface, and the notch is the mounting portion; the first direction is perpendicular to the second direction.

[0007] The two frequency selective surface units can be plugged in along the second direction, and both frequency selective surface units can be plugged in through corresponding notches, and finally contact and limit through two step surfaces to form a three-dimensional posture.

[0008] In a possible design, along the second direction, the step surface is located at a 1 / 2 position of the dielectric layer.

[0009] Among them, by locating the step surface at the 1 / 2 position of the dielectric layer in the second direction, it can be ensured that after the first plug board and the second plug board are plugged in, the two ends of the first plug board and the second plug board in the second direction can remain flush, thereby improving the overall structural stability of the frequency selective surface device.

[0010] In a possible design, along a first direction of the dielectric layer, a first gap is provided between the second metal layer and an edge of the dielectric layer.

[0011] Among them, due to the existence of the above-mentioned first gap, the two adjacent frequency selective surface units do not contact each other, and the width between the two second metal layers of the two adjacent frequency selective surface units is twice the width of the first gap. Parts of the second metal layers on both sides of the first gap can jointly form a dual-conductor transmission line, which can serve as a transmission channel for electromagnetic waves within the passband.

[0012] In a possible design, along the first direction of the dielectric layer, the first metal layer extends to the edge of the dielectric layer, so as to be electrically connected to the first metal layer on another adjacent frequency selective surface unit.

[0013] Among them, between the multiple frequency selective surface units arranged in an array, after two adjacent dielectric layers are butted at the edges, the first metal layers on the two adjacent dielectric layers can also be butted at the edges of the dielectric layers, thereby enabling electrical connection of the multiple first metal layers arranged in an array, facilitating processing and manufacturing.

[0014] In a possible design, the first metal layer includes a first segment, a second segment and a third segment, one end of the second segment is connected to the first segment, the other end of the second segment is connected to the third segment, the first segment and the third segment extend along a first direction of the dielectric layer, and the third segment extends away from one end of the second segment to an edge of the dielectric layer, and the second segment extends along a second direction of the dielectric layer; the first segment is located at the center of the dielectric layer, and there is a gap between the third segment and the mounting portion.

[0015] Among them, by bending the second and third sections, the third section can be extended to the edge of the dielectric layer to facilitate connection with another first metal layer arranged in an adjacent array, and can also maintain a certain distance from the step surface in the second direction to avoid metal contact between two frequency selective surface units plugged into each other. In addition, the first section has a large extension length in the first direction and is located at the center of the dielectric layer, which is conducive to generating electrical response and improving performance.

[0016] In a possible design, the second metal layer includes a first metal patch and a second metal patch, a second gap is arranged between the first metal patch and the second metal patch, and the first metal patch and the second metal patch form the capacitive structure at the second gap.

[0017] The second gap can form a distributed capacitor, and the size of the capacitor can be adjusted by adjusting the width of the second gap, so that the second metal layer can generate the required magnetic response. In addition, the capacitor can be realized by simply adjusting the positional relationship of the two metal patches, which is conducive to simplifying the structure, reducing the number of components, and achieving lightweight.

[0018] In a possible design, at least one of the first metal patch and the second metal patch is provided with a protrusion, and the other is provided with a recessed portion, the protrusion extends into the recessed portion, and there is the second gap between the protrusion and the inner wall of the recessed portion, and the protrusion and the recessed portion cooperate to form the capacitive structure.

[0019] Among them, by the cooperation of the protrusion and the recess, an interdigital capacitor can be formed, which can work stably at high frequencies, has low losses and excellent frequency response characteristics. Among them, by adjusting the length, width, number of the protrusion and the gap between the protrusion and the recess, the capacitance can be adjusted, and then the magnetic field can be adjusted.

[0020] In a possible design, the first metal patch and the second metal patch are located in the same plane in a direction perpendicular to the thickness of the dielectric layer. This embodiment can be applicable to a scenario using a single-layer dielectric plate with uniform thickness, and also facilitates the overall arrangement of the second metal layer.

[0021] In a possible design, the first metal patch and the second metal patch are located in different planes in a direction perpendicular to the thickness of the dielectric layer.

[0022] In a possible design, the dielectric layer has multiple layers, and the first metal patch and the second metal patch are arranged on both sides of a portion of the dielectric layer in the thickness direction. The first metal patch and the second metal patch can also couple to generate a magnetic response, and this embodiment can be applied to scenarios with multiple dielectric layers or scenarios with uneven thickness of the dielectric layer.

[0023] In a possible design, the capacitive structure or device and the second metal layer are located on the same side of the dielectric layer, thereby facilitating the arrangement of the second metal layer and the capacitive structure or device and helping to reduce the volume of the frequency selective surface unit.

[0024] In a possible design, the capacitive structure or device and the second metal layer are respectively located on both sides of the dielectric layer, and the capacitive structure or device is electrically connected to the second metal layer, thereby allowing the capacitive structure or device to be flexibly arranged.

[0025] In a possible design, a first metal connection structure is provided on the dielectric layer, and the capacitive structure or device is electrically connected to the second metal layer through the first metal connection structure. The first metal connection structure does not occupy additional space, and can ensure the reliability of the connection between the capacitive structure or device and the second metal layer.

[0026] In a possible design, the frequency selective surface unit further includes a third metal patch, the third metal patch and the second metal layer are located on the same side of the dielectric layer, and there is a gap between the third metal patch and the second metal layer, and the third metal patch is electrically connected to the first metal layer. Since there is no dielectric plate between the second metal layer and the third metal patch, the electromagnetic coupling effect between the second metal layer and the third metal patch can be improved.

[0027] In a possible design, a second metal connection structure is provided on the dielectric layer, and the third metal patch is electrically connected to the first metal layer through the second metal connection structure. The second metal connection structure does not occupy additional space of the frequency selective surface unit, and can ensure the reliability of the connection between the first metal layer and the third metal patch.

[0028] In a possible design, the dielectric constant of the dielectric layer is between 1 and 10 to ensure that the frequency selective surface unit has a higher passband bandwidth; the thickness of the dielectric layer is greater than or equal to 0.1 mm, which can ensure the reliability of the overall structure of the frequency selective surface unit on the one hand, and facilitate processing and manufacturing on the other hand.

[0029] In a possible design, the thickness of the first metal layer and the second metal layer is greater than or equal to 0.035 mm, which is beneficial to improving the effect of electromagnetic wave reflection and is also easy to process.

[0030] The second aspect of the present application also provides a frequency selective surface device, which includes a plurality of frequency selective surface units provided by the first aspect of the present application, the plurality of frequency selective surface units include a plurality of first frequency selective surface units and a plurality of second frequency selective surface units, the plurality of first frequency selective surface units are arranged in an array in a third direction, the plurality of second frequency selective surface units are arranged in an array in a fourth direction, and the first frequency selective surface units and the second frequency selective surface units are cross-connected.

[0031] In a possible design, the intersection angle between the first frequency selective surface unit and the second frequency selective surface unit is between 60° and 120°, so that the overall structure of the frequency selective surface device can meet application requirements in different scenarios.

[0032] In a possible design, the first frequency selective surface unit and the second frequency selective surface unit are an integrally formed structure, so there is no need to set the above-mentioned first card slot and second card slot on the first frequency selective surface unit and the second frequency selective surface unit, which can ensure the overall reliability of the structure on the one hand, and facilitate processing and manufacturing on the other hand, improve efficiency and save costs.

[0033] In a possible design, the dielectric layers of two adjacent first frequency selective surface units are connected so that a first slot is formed between the mounting parts at the connection of the two adjacent dielectric layers; the dielectric layers of two adjacent second frequency selective surface units are connected so that a second slot is formed between the mounting parts at the connection of the two adjacent dielectric layers, and the step surface of the second slot contacts and limits the step surface of the first slot, thereby facilitating the plugging and fixing of the first frequency selective surface unit and the second frequency selective surface unit.

[0034] In a possible design, the dielectric layer of the plurality of first frequency selective surface units is an integral structure formed in one piece, and the dielectric layer of the plurality of second frequency selective surface units is an integral structure formed in one piece; the first card slot and the second card slot are processed and formed on the integrally formed dielectric layer, thereby facilitating processing and improving structural reliability.

[0035] In a possible design, the first metal layer of multiple first frequency selective surface units is an integral structure formed in one piece, and the first metal layer of multiple second frequency selective surface units is an integral structure formed in one piece, thereby facilitating the processing of the first metal layer, while ensuring the structural consistency of the first metal layer in each frequency selective surface unit, and improving the overall structural reliability of the plug-in board.

[0036] In a possible design, the number of the first frequency selective surface units and the number of the second frequency selective surface units are both greater than or equal to eight.

[0037] The third aspect of the present application also provides an antenna system, which includes the frequency selective surface unit provided by the first aspect of the present application or the frequency selective surface device provided by the second aspect of the present application; wherein the antenna system can be an antenna system for a communication device, and the communication device can be a wireless communication device, such as a base station.

[0038] The fourth aspect of the present application also provides a communication device, which includes the frequency selective surface unit provided in the first aspect of the present application or the frequency selective surface device provided in the second aspect of the present application. In addition, the base station may also include other components, for example, some signal processing components, such as RRU, or BBU; it may also include a power supply for power supply and connection components for connecting various components (such as various connectors, optical fibers, or cables, etc.); wherein the communication device may be a wireless communication device, for example, a base station; the frequency selective surface unit or the frequency selective surface device of the present application may be integrated in an antenna system, that is, the communication device may include an antenna system, and the antenna system includes the frequency selective surface unit or the frequency selective surface device of the present application.

[0039] It should be understood that the foregoing general description and the following detailed description are exemplary only and are not restrictive of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 A schematic diagram of the structure of a frequency selective surface device provided in an embodiment of the present application at a viewing angle;

[0041] Figure 2 A schematic structural diagram of a frequency selective surface device provided in an embodiment of the present application from another perspective;

[0042] Figure 3 A schematic diagram of the structure of a frequency selective surface unit provided in one embodiment of the present application at a viewing angle;

[0043] Figure 4 A schematic structural diagram of a frequency selective surface unit provided in another embodiment of the present application at a viewing angle;

[0044] Figure 5 A schematic diagram of cross-coordination of two frequency selective surface units provided in an embodiment of the present application;

[0045] Figure 6 A schematic diagram of an array arrangement of a plurality of first frequency selective surface units;

[0046] Figure 7 A transmission coefficient (S21) curve diagram of the frequency selective surface device provided in an embodiment of the present application when the electromagnetic wave is vertically incident;

[0047] Figure 8 A transmission coefficient (S21) curve diagram of the frequency selective surface device provided in an embodiment of the present application when an electromagnetic wave is obliquely incident under TE polarization;

[0048] Fig. 9 A transmission coefficient (S21) curve diagram of a frequency selective surface device provided in an embodiment of the present application when an electromagnetic wave is obliquely incident under TM polarization;

[0049] Fig.10 An exploded diagram of a frequency selective surface unit provided by an embodiment of the present application;

[0050] Fig.11 A front view of a dielectric layer provided in an embodiment of the present application;

[0051] Fig.12 It is a partial schematic diagram of a first plug-in board and a second plug-in board in a frequency selective surface device before being plugged in;

[0052] Fig.13 It is a partial schematic diagram of a first plug-in board and a second plug-in board in a frequency selective surface device after being plugged in;

[0053] Fig.14 A front view of a frequency selective surface unit provided in an embodiment of the present application;

[0054] Fig.15 A front view of an array arrangement of multiple frequency selective surface units provided in an embodiment of the present application;

[0055] Fig.16 A rear view of a frequency selective surface unit provided in an embodiment of the present application;

[0056] Fig.17 A schematic diagram of the structure of the first metal layer provided in an embodiment of the present application;

[0057] Fig.18 A front view of a first metal patch provided in an embodiment of the present application;

[0058] Fig.19 A front view of a first metal patch provided in an embodiment of the present application;

[0059] Fig. 20 An exploded diagram of a frequency selective surface unit provided in another embodiment of the present application;

[0060] Fig.21 An exploded diagram of a frequency selective surface unit provided in yet another embodiment of the present application;

[0061] Fig. 22 An exploded view of a frequency selective surface unit provided in yet another embodiment of the present application.

[0062] Marking Description:

[0063] 100-first plugboard;

[0064] 110-first card slot;

[0065] 200-second plug board;

[0066] 210 - second card slot;

[0067] 10-Frequency Selective Surface Unit;

[0068] 10a-a first frequency selective surface unit;

[0069] 10b-second frequency selective surface unit;

[0070] 11- dielectric layer;

[0071] 111-installation part;

[0072] 111a-notch;

[0073] 111b-step surface;

[0074] 112-first metal connection structure;

[0075] 113- second metal connection structure;

[0076] 12- first metal layer;

[0077] 121- first paragraph;

[0078] 122-Second paragraph;

[0079] 123- third paragraph;

[0080] 13- second metal layer;

[0081] 131-first metal patch;

[0082] 132- second metal patch;

[0083] 133- raised portion;

[0084] 134-depression;

[0085] 14-capacitive structure;

[0086] 141- a first metal sheet;

[0087] 142 - second metal sheet;

[0088] 15- Transmission channel;

[0089] 16- third metal patch;

[0090] X1 - first direction;

[0091] Y1-second direction;

[0092] X2-third direction;

[0093] Y2-fourth direction;

[0094] H1 - first gap;

[0095] H2 - Second gap.

[0096] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present application and, together with the description, serve to explain the principles of the present application. DETAILED DESCRIPTION

[0097] In order to better understand the technical solution of the present application, the embodiments of the present application are described in detail below in conjunction with the accompanying drawings. It should be understood that the specific embodiments described here are only used to explain the present application and are not used to limit the present application.

[0098] In the description of this application, unless otherwise clearly specified and limited, the terms "first" and "second" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance; unless otherwise specified or explained, the term "plurality" refers to two or more; the terms "connected" and "fixed" should be understood in a broad sense, for example, "connected" can be a fixed connection, a detachable connection, an integral connection, or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0099] Frequency Selective Surface (FSS) is a periodically arranged artificial electromagnetic metamaterial structure, which can artificially control its transmittance and reflectivity according to the incident frequency of the electromagnetic wave, thereby effectively solving the spatial coupling problem introduced by narrow spectrum resources or compact system design. Theoretically, the frequency selective surface can achieve complete transmission or reflection of a single frequency point at any single incident angle. However, in actual engineering application scenarios, the regulatory effect of the frequency selective surface on electromagnetic waves is weakened due to factors such as the incident angle and the working bandwidth. Among them, the more typical problem is that it is difficult to achieve large-angle stability of the frequency selective surface within a wider frequency band.

[0100] To this end, an embodiment of the present application provides a frequency selective surface unit, Figure 1 A schematic diagram of the structure of a frequency selective surface device provided in an embodiment of the present application at a viewing angle, Figure 2 A schematic diagram of the structure of the frequency selective surface device provided in the embodiment of the present application from another perspective, referring to Figure 1 and Figure 2A plurality of the frequency selective surface units can constitute a frequency selective surface device, which can be applied to antenna systems, antenna covers and other scenes. The frequency selective surface device composed of a plurality of frequency selective surface units can use the electromagnetic parameter control method to match the equivalent characteristic impedance of the frequency selective surface device with the port impedance under oblique incidence, thereby achieving large-angle stability characteristics.

[0101] Figure 3 A schematic diagram of the structure of a frequency selective surface unit provided in an embodiment of the present application at a viewing angle, Figure 4 A schematic diagram of the structure of a frequency selective surface unit provided in another embodiment of the present application at a viewing angle, and referring to Figure 3 and Figure 4 In this embodiment, the frequency selective surface unit includes a dielectric layer 11, a first metal layer 12 and a second metal layer 13. The first metal layer 12 is arranged on one side of the dielectric layer 11, and the second metal layer 13 is arranged on the side of the dielectric layer 11 away from the first metal layer 12. A capacitive structure or device is arranged on the second metal layer 13. Figure 4 The second metal layer 13 is exemplarily shown to be provided with a capacitive structure 14. Of course, a capacitive device, such as a lumped capacitor, may also be connected to the second metal layer 13. The dielectric layer 11 is provided with a mounting portion. Figure 5 This is a schematic diagram of the cross-cooperation of two frequency selective surface units 10 provided in the embodiment of the present application, referring to Figure 5 The mounting portion is used to cross-connect two frequency selective surface units 10 .

[0102] The dielectric layer 11 may be a flame retardant material (FR-4) dielectric board, a Rogers dielectric board, a mixed dielectric board of Rogers and FR-4, etc. Here, FR-4 is a code for a grade of flame retardant material, and the Rogers dielectric board is a high-frequency board. In this embodiment, the dielectric constant of the dielectric layer 11 may be between 1 and 10 to ensure that the frequency selective surface unit 10 has a high passband bandwidth. In addition, the thickness of the dielectric layer 11 may be greater than 0.1 mm, which can ensure the reliability of the overall structure of the frequency selective surface unit 10 on the one hand, and facilitate processing and manufacturing on the other hand.

[0103] In this embodiment, refer to Figure 1 and Figure 2When a plurality of the frequency selective surface units 10 are used to form a frequency selective surface device, the plurality of the frequency selective surface units 10 can be divided into a plurality of first frequency selective surface units 10a and a plurality of second frequency selective surface units 10b. The plurality of first frequency selective surface units 10a are arranged in an array in the third direction X2, and the plurality of second frequency selective surface units 10b are arranged in an array in the fourth direction Y2. The first frequency selective surface units 10a and the second frequency selective surface units 10b are cross-connected. The third direction X2 and the fourth direction Y2 form a certain angle, referring to Figure 5 , the angle is also the intersection angle α between the first frequency selective surface unit 10a and the second frequency selective surface unit 10b, and the angle α can be between 60 and 120°. Exemplarily, the angle α can be 60°, 70°, 80°, 90°, 100°, 110°, 120°, etc., so that the overall structure of the frequency selective surface device can meet the application requirements in different scenarios.

[0104] Among them, the mounting part on the dielectric layer 11 of the first frequency selective surface unit 10a can be connected to the mounting part on the dielectric layer 11 of the second frequency selective surface unit 10b, thereby ensuring that a stable angle is maintained between the first frequency selective surface unit 10a and the second frequency selective surface unit 10b, and at the same time facilitating the realization of stable dual polarization.

[0105] The first FSS unit 10a and the second FSS unit 10b may have the same structure. For ease of description, this embodiment takes the first FSS unit 10a as an example. Figure 6 A schematic diagram of an array arrangement of a plurality of first frequency selective surface units 10a is shown in FIG. Figure 6 A first slot 110 can be formed between any two adjacent first frequency selective surface units 10a arranged in an array and between two adjacent dielectric layers 11 through a mounting portion. Similarly, a second slot 210 can be formed between any two adjacent second frequency selective surface units 10b arranged in an array and between two adjacent dielectric layers 11 through a mounting portion. The first frequency selective surface unit 10a and the second frequency selective surface unit 10b can be plugged and fixed through the first slot 110 and the second slot 210, thereby forming a frequency selective surface device.

[0106] In addition, the first metal layer 12 can generate an electrical response, and since the second metal layer 13 is provided with a capacitive structure or device, the second metal layer 13 can generate a magnetic response, so that the equivalent dielectric constant and the magnetic permeability of the first frequency selective surface unit 10a and the second frequency selective surface unit 10b can be controlled, so that the frequency selective surface device with the above-mentioned three-dimensional structure can have high wave transmittance in the first working frequency band with a relatively high frequency, and high reflectivity and high selectivity in the second working frequency band with a relatively low frequency, and low loss. At the same time, the frequency selective surface device can have dual-polarization large-angle stability.

[0107] The first metal layer 12 and the second metal layer 13 may be metal sheets with a certain thickness, and the thickness of the first metal layer 12 and the second metal layer 13 is greater than or equal to 0.01 mm, which is conducive to improving the effect of electromagnetic wave reflection and is also convenient for processing. In addition, in some special application scenarios, the thickness of the first metal layer 12 and the second metal layer 13 may also be less than 0.01 mm, which is not limited in this embodiment.

[0108] In one embodiment, the dielectric layer 11 of the plurality of first frequency selective surface units 10a is an integral structure formed in one piece, and the dielectric layer 11 of the plurality of second frequency selective surface units 10b is an integral structure formed in one piece. Since the first frequency selective surface unit 10a and the second frequency selective surface unit 10b have the same structure, for ease of description, this embodiment is described by taking the first frequency selective surface unit 10a as an example. Figure 6 For example, the dielectric layer 11 may be a Rogers dielectric plate having a certain length. The first metal layer 12 and the second metal layer 13 may be connected to both sides of the dielectric plate, so that a plurality of first frequency selective surface units 10a arranged in an array may be manufactured on a dielectric plate. For ease of description, the present embodiment may define a plurality of first frequency selective surface units 10a arranged in an array as a whole as a first plug-in board 100. Similarly, a plurality of second frequency selective surface units 10b arranged in an array may be defined as a whole as a second plug-in board 200. Figure 1, the first plugboard 100 extends along the third direction X2, and the second plugboard 200 extends along the fourth direction Y2. The first plugboard 100 can be plugged with the second plugboard 200 through the first card slot 110 and the second card slot 210 to form a frequency selective surface device. Among them, a plurality of first plugboards 100 can be arranged in parallel and spaced in the fourth direction Y2, and a plurality of second plugboards 200 can be arranged in parallel and spaced in the third direction X2. Exemplarily, the number of first plugboards 100 in the fourth direction Y2 can be greater than or equal to 8, and the number of frequency selective surface units 10 on the first plugboard 100 is also greater than or equal to 8, the number of second plugboards 200 in the third direction X2 can also be greater than or equal to 8, and the number of frequency selective surface units 10 on the second plugboard 200 is also greater than or equal to 8.

[0109] Among them, the above-mentioned cross-arranged plug-in boards can constitute dual polarization. Of course, in some other application scenarios, only one plug-in board can be used or multiple plug-ins can be arranged in an array in a single direction to constitute single polarization. The specific application form can be flexibly selected according to the specific scenario.

[0110] When the dielectric layer 11 of each FSS unit 10 is a part of the overall structure, the first slot 110 and the second slot 210 can be processed and formed on the integrally formed dielectric layer 11, thereby facilitating processing and improving structural reliability.

[0111] In addition, in some other embodiments, the first frequency selective surface unit 10a and the second frequency selective surface unit 10b may be an integrally formed structure, for example, they may be integrally formed by 3D printing. Figure 1 The frequency selective surface device shown does not need to be provided with the first slot 110 and the second slot 210 on the first frequency selective surface unit 10a and the second frequency selective surface unit 10b, thereby ensuring the overall reliability of the structure on the one hand, and facilitating processing and manufacturing on the other hand, improving efficiency and saving costs.

[0112] Therefore, the frequency selective surface device with the above structure can still maintain good filtering characteristics under large-angle oblique incidence conditions, has high reflection characteristics in the second working frequency band with relatively low frequency, has high wave transmission characteristics in the first working frequency band with relatively high frequency, and has good dual-polarization large-angle stability.

[0113] Figure 7 The transmission coefficient (S21) curve of the frequency selective surface device provided in the embodiment of the present application when the electromagnetic wave is vertically incident, the horizontal axis is the frequency, the unit is GHz, and the vertical axis is the transmission coefficient (dB), refer to Figure 7, 1.0GHz~2.5GHz frequency band is the second frequency band, 3.0GHz~4.5GHz frequency band is the first frequency band, 2.5GHz~3.0GHz is the transition frequency band, in the above second frequency band, the frequency selective surface device has a strong reflection characteristic, and its reflection coefficient is close to 0dB, in the above first frequency band, the frequency selective surface device shows a strong wave transmission characteristic, and its insertion loss is less than 0.3dB. In the above transition frequency band, there is a transmission zero point in the transmission coefficient curve, so that the entire transition frequency band has a high steepness characteristic, and its steep drop rate is 70dB / GHz, so that the frequency selective surface device has a high roll-off rate. In addition, the overall profile of the frequency selective surface device is 0.18λ, λ is the center frequency wavelength of the first working frequency band, and it has a good low profile characteristic.

[0114] In addition, the first frequency band, the second frequency band, and the transition frequency band are not limited to the above-mentioned frequency band ranges. In some other embodiments, the first frequency band, the second frequency band, and the transition frequency band may also correspond to other frequency interval values, and may also achieve the above-mentioned effects similar to those of the present application, which will not be elaborated in this embodiment.

[0115] Figure 8 The transmission coefficient (S21) curve of the frequency selective surface device provided in the embodiment of the present application when the electromagnetic wave is obliquely incident under TE polarization, the horizontal axis is the frequency, the unit is GHz, and the vertical axis is the transmission coefficient (dB), refer to Figure 8 Curve a1 represents the S21 curve when the electromagnetic wave is incident normally, curve a2 represents the S21 curve when the electromagnetic wave is incident at 45° obliquely under TE polarization, and curve a3 represents the S21 curve when the electromagnetic wave is incident at 60° obliquely under TE polarization. Figure 8 It can be seen that, in the case of oblique incidence of TE polarized electromagnetic waves, the frequency selective surface device provided in this embodiment has a very high suppression degree in the second working frequency band, the suppression degree is greater than 10dB, and has very good wave transmission characteristics in the first working frequency band with a higher frequency, and the insertion loss within the band is less than 0.5dB. In addition, at the transmission zero point position of the transmission coefficient in the transition frequency band, the curve of the case of oblique incidence of electromagnetic waves is slightly offset relative to the case of normal incidence of electromagnetic waves, but remains stable. Therefore, the case of oblique incidence of electromagnetic waves also has a high steepness drop rate in the above-mentioned transition frequency band.

[0116] Fig. 9 The transmission coefficient (S21) curve of the frequency selective surface device provided in the embodiment of the present application when the electromagnetic wave is obliquely incident under TM polarization, the horizontal axis is the frequency, the unit is GHz, and the vertical axis is the transmission coefficient (dB), refer to Fig. 9 Curve b1 represents the S21 curve when the electromagnetic wave is incident normally, curve b2 represents the S21 curve when the electromagnetic wave is incident obliquely at 45° under TE polarization, and curve b3 represents the S21 curve when the electromagnetic wave is incident obliquely at 60° under TM polarization. Fig. 9 It can be seen that, in the case of oblique incidence of TM polarized electromagnetic waves, the frequency selective surface device provided in this embodiment has a very high suppression degree in the second working frequency band with a relatively low frequency, and the suppression degree is greater than 10dB, and has very good wave transmission characteristics in the first working frequency band with a relatively high frequency, and the insertion loss within the band is less than 0.5dB. In addition, at the transmission zero point position of the transmission coefficient in the transition frequency band, the curve of the case of oblique incidence of electromagnetic waves is slightly offset relative to the case of normal incidence of electromagnetic waves, but it remains stable. Therefore, the case of oblique incidence of electromagnetic waves also has a high steepness drop rate in the above-mentioned transition frequency band.

[0117] In summary, the frequency surface selection device provided by the present application is able to achieve low profile and lightweight characteristics by plugging a first plug-in board 100 including a plurality of first frequency selective surface units 10a and a second plug-in board 200 including a plurality of second frequency selective surface units 10b into each other, and loading an electromagnetic resonance structure composed of a first metal layer 12 and a second metal layer 13 on each frequency selective surface unit. The frequency selective surface device has the advantages of high wave transmittance in a first working frequency band with a relatively high frequency, high selectivity with high suppression degree, low loss, etc. in a second working frequency band with a relatively low frequency; and the frequency selective surface device can still maintain good filtering characteristics under large-angle oblique incidence, has high reflection characteristics in the second working frequency band with a relatively low frequency, and has high wave transmittance characteristics in the first working frequency band with a relatively high frequency, thereby having good dual-polarization large-angle stability.

[0118] Since each FSS unit 10 in the FSS device has the same structure, for the convenience of description, the structure of the FSS unit 10 will be described in detail below.

[0119] Fig.10 An exploded view of a frequency selective surface unit 10 provided in one embodiment of the present application is shown in FIG. Fig.10 The first metal layer 12 and the second metal layer 13 are respectively arranged on both sides of the dielectric layer 11, wherein: Fig.11 This is a front view of the dielectric layer 11 provided in the embodiment of the present application, referring to Fig.11 , along the first direction X1 of the dielectric layer 11, at least one side edge of the dielectric layer 11 is provided with a notch 111a, along the second direction Y1 of the dielectric layer 11, one end of the notch 111a penetrates one side edge of the dielectric layer 11, and the other end of the notch 111a forms a step surface 111b, and the notch 111a is a mounting portion; the first direction X1 is perpendicular to the second direction Y1. Among them, the dielectric layer 11 can be square, polygonal, etc. In this embodiment, the dielectric layer 11 can be preferably rectangular, the first direction X1 is the width direction of the dielectric layer 11, and the second direction Y1 is the length direction of the dielectric layer 11.

[0120] Among them, refer to Figure 5 The two FSS units 10 can be plugged in along the second direction Y1. Both FSS units 10 can be plugged in through the corresponding notches 111a, and finally contacted and limited by the two step surfaces 111b to form a three-dimensional posture.

[0121] In one embodiment, Fig.12 FIG. 1 is a partial schematic diagram of a first plug-in board 100 and a second plug-in board 200 in a frequency selective surface device before being plugged in. Fig.13 FIG. 1 is a partial schematic diagram of the first plug board 100 and the second plug board 200 in the frequency selective surface device after plugging together, referring to FIG. Fig.12 and Fig.13 As described above, multiple first frequency selective surface units 10a can use the same dielectric layer 11 to form a first plugboard 100 with an integral structure. Similarly, multiple second frequency selective surface units 10b can also use the same dielectric layer 11 to form a second plugboard 200 with an integral structure. Taking the first plugboard 100 as an example, it can be understood that after multiple first frequency selective surface units 10a are arranged in an array in the length direction of the first plugboard 100, the notches 111a on two adjacent dielectric layers 11 can be connected to form a first card slot 110. Of course, the first card slot 110 can be directly processed and formed on a dielectric board by laser cutting or cutting. Similarly, the second card slot 210 on the second plugboard 200 can also be processed and formed in the same processing method as the first card slot 110, which will not be repeated here.

[0122] Reference Fig.12 Before the first plugboard 100 and the second plugboard 200 are plugged in, the first plugboard 100 and the second plugboard 200 are placed in opposite directions so that the opening directions of the first card slot 110 and the second card slot 210 are opposite to each other. Fig.13 Then, the first card slot 110 and the second card slot 210 can be engaged with each other, and the bottom of the first card slot 110 and the bottom of the second card slot 210 can be contacted and limited, so that the first plugboard 100 and the second plugboard 200 can have a stable three-dimensional posture.

[0123] In one embodiment, referring to Fig.11, along the second direction Y1, the step surface 111b is located at 1 / 4 to 1 / 2 of the dielectric layer 11. In this embodiment, along the second direction Y1, the step surface 111b is preferably located at 1 / 2 of the dielectric layer 11. When a plurality of frequency selective surface units 10 are arranged in an array to form a first plug board 100 and a second plug board 200, the mounting portion between two adjacent frequency selective surfaces in the first plug board 100 or the second plug board 200 constitutes a first card slot 110 and a second card slot 210, and the step surface 111b accordingly constitutes the bottom of the first card slot 110 and the second card slot 210. Among them, by making the step surface 111b located at 1 / 2 of the dielectric layer 11 in the second direction Y1, it can be ensured that after the first plug board 100 and the second plug board 200 are plugged in, the two ends of the first plug board 100 and the second plug board 200 in the second direction Y1 can remain flush, thereby improving the overall structural stability of the frequency selective surface device. In addition, in some other special application scenarios, along the second direction Y1, the step surface 111b may also be located at a position other than 1 / 4 to 1 / 2 of the dielectric layer 11, which is not limited in this embodiment.

[0124] In one embodiment, Fig.14 A front view of a frequency selective surface unit 10 provided in an embodiment of the present application, referring to Fig.14 Along the first direction X1 of the dielectric layer 11 , a first gap H1 is provided between the second metal layer 13 and the edge of the dielectric layer 11 . Fig.15 This is a front view of a plurality of frequency selective surface units 10 provided in an embodiment of the present application when arranged in an array, referring to Fig.15 Due to the existence of the above-mentioned first gap H1, the two adjacent frequency selective surface units 10 do not contact each other, and the width between the two second metal layers 13 of the two adjacent frequency selective surface units 10 is twice the width of the first gap H1. Parts of the second metal layers 13 on both sides of the first gap H1 can jointly form a dual-conductor transmission line, which can serve as a transmission channel 15 for electromagnetic waves within the passband.

[0125] In one embodiment, Fig.16 The rear view of the frequency selective surface unit 10 provided in the embodiment of the present application is shown in FIG. Fig.16 , along the first direction X1 of the dielectric layer 11, the first metal layer 12 extends to the edge of the dielectric layer 11, and is used to be electrically connected to the first metal layer 12 on another adjacent frequency selective surface unit. Figure 6, between the multiple frequency selective surface units 10 arranged in an array, after two adjacent dielectric layers 11 are butted at the edge, the first metal layers 12 on the two adjacent dielectric layers 11 can also be butted at the edge of the dielectric layer 11, so that the multiple first metal layers 12 arranged in the array can be electrically connected. In one embodiment, when each frequency selective surface unit 10 arranged in an array uses the same dielectric plate, each first metal layer 12 can be connected to a position on the dielectric plate corresponding to each frequency selective surface unit 10, and two adjacent first metal layers 12 can be connected at the symmetric center of the two adjacent frequency selective surface units 10. In one embodiment, in order to facilitate the processing of the first metal layer 12, ensure the structural consistency of the first metal layer 12 in each frequency selective surface unit 10, and improve the overall structural reliability of the plug board, the first metal layer 12 in each selection surface unit is integrally formed with a metal part, that is, the metal part is a part, and multiple first metal layers 12 can be formed at one time during the processing, so that multiple first metal layers 12 can be set at the corresponding frequency selective surface units 10 on a first plug board 100, or multiple first metal layers 12 can be set at the corresponding frequency selective surface units 10 on a second plug board 200.

[0126] In one embodiment, Fig.17 The schematic diagram of the structure of the first metal layer 12 provided in the embodiment of the present application is shown in FIG. Fig.17 The first metal layer 12 includes a first segment 121, a second segment 122 and a third segment 123, one end of the second segment 122 is connected to the first segment 121, and the other end of the second segment 122 is connected to the third segment 123, the first segment 121 and the third segment 123 extend along the first direction X1 of the dielectric layer 11, and the third segment 123 extends away from one end of the second segment 122 to the edge of the dielectric layer 11, the second segment 122 extends along the second direction Y1 of the dielectric layer 11, the first segment 121 is located at the center of the dielectric layer 11, and there is a gap between the third segment 123 and the mounting portion.

[0127] The first section 121 and the third section 123 can be arranged in parallel, and the second section 122 is arranged perpendicular to the first section 121 and the third section 123, respectively. Fig.16, the first section 121 has a large extension length in the first direction X1 and is located at the center of the dielectric layer 11, which is conducive to generating an electrical response and improving performance. Since the step surface 111b of the notch 111a is also located at the center of the edge of the dielectric layer 11, if the first section 121 extends to the edge of the dielectric layer 11, it is easy to cause the first metal layer 12 to cover the edge of the step surface 111b. When two frequency selective surface units 10 are plugged in, metal contact is easy to occur at the step surface 111b, thereby causing short circuits, reduced performance and other problems. To this end, in this embodiment, by bending the second section 122 and the third section 123, the third section 123 can be extended to the edge of the dielectric layer 11 to facilitate connection with another first metal layer 12 arranged in an adjacent array, and can maintain a certain distance between the step surface 111b in the second direction Y1 to avoid metal contact between the two frequency selective surface units 10 plugged in.

[0128] In one embodiment, referring to Fig.14 The second metal layer 13 includes a first metal patch 131 and a second metal patch 132, a second gap H2 is provided between the first metal patch 131 and the second metal patch 132, and the first metal patch 131 and the second metal patch 132 form a capacitive structure 14 at the second gap H2. The second gap H2 can form a distributed capacitor, and the size of the distributed capacitor can be adjusted by adjusting the width of the second gap H2 so that the second metal layer 13 can generate the desired magnetic response. In addition, the distributed capacitor can be realized by simply adjusting the positional relationship of the two metal patches, which is conducive to simplifying the structure, reducing the number of components, and achieving lightweight.

[0129] In one embodiment, Fig.18 This is a front view of the first metal patch 131 provided in the embodiment of the present application. Fig.19 This is a front view of the first metal patch 131 provided in the embodiment of the present application, referring to Fig.18 and Fig.19 At least one of the first metal patch 131 and the second metal patch 132 is provided with a protruding portion 133, and the other is provided with a recessed portion 134. Fig.14, the raised portion 133 extends into the recessed portion 134, and a second gap H2 is provided between the raised portion 133 and the inner wall of the recessed portion 134, and the raised portion 133 and the recessed portion 134 cooperate to form the capacitive structure 14. Thus, through the cooperation of the raised portion 133 and the recessed portion 134, an interdigital capacitor can be formed, which can work stably at high frequencies, has low losses and excellent frequency response characteristics. Among them, by adjusting parameters such as the length, width, and number of the raised portion 133 and the gap between the raised portion 133 and the recessed portion 134, the size of the interdigital capacitor can be adjusted, thereby achieving the adjustment of the magnetic field. For example, referring to Fig.14 , the width of the second gap H2 can be between 0.2 mm and 0.6 mm, and the length of the protrusion 133 in the second direction Y1 can be between 1 mm and 4 mm. Of course, in other embodiments, the length of the protrusion 133 and the width of the second gap H2 are not limited to the above numerical ranges, and this embodiment does not limit this.

[0130] Among them, refer to Fig.18 and Fig.19 The first metal patch 131 and the second metal patch 132 are approximately a "C" shaped structure, referring to Fig.14 When the first metal patch 131 and the second metal patch 132 are arranged relative to each other, it is beneficial to form a second gap H2 with a smaller width between the two ends of the first metal patch 131 and the second metal patch 132, and the first metal patch 131 and the second metal patch 132 can form a nearly annular structure, which is beneficial to generate a magnetic response.

[0131] In one embodiment, referring to Fig.10 The capacitive structure 14 and the second metal layer 13 are located on the same side of the dielectric layer 11, thereby facilitating the arrangement of the second metal layer 13 and the capacitive structure 14, and helping to reduce the volume of the frequency selective surface unit 10. Fig.14 As described above, the capacitive structure 14 can be formed by the second gap H2 between the first metal patch 131 and the second metal patch 132. The capacitive structure 14 can be symmetrically arranged at both ends of the second metal layer 13 in the second direction Y1. In some other embodiments, a capacitive device such as a lumped capacitor can also be used to replace the capacitive structure 14, and its arrangement method is similar to that of the capacitive structure 14, which will not be described in detail in this embodiment.

[0132] In one embodiment, Fig. 20 The exploded view of the frequency selective surface unit 10 provided in another embodiment of the present application is shown in FIG. Fig. 20The capacitive structure 14 and the second metal layer 13 can be located on both sides of the dielectric layer 11 respectively, and the capacitive structure 14 is electrically connected to the second metal layer 13, so that the capacitive structure 14 can be flexibly arranged.

[0133] Among them, a first metal connection structure 112 is provided on the dielectric layer 11, and the capacitive structure 14 is electrically connected to the second metal layer 13 through the first metal connection structure 112. The first metal connection structure 112 does not occupy additional space, and can ensure the reliability of the connection between the capacitive structure 14 and the second metal layer 13. For example, referring to Fig. 20 The capacitive structure 14 may include a first metal sheet 141 and a second metal sheet 142, with a second gap H2 between the first metal sheet 141 and the second metal sheet 142. The second metal layer 13 may also include a first metal patch 131 and a second metal patch 132. The first metal sheet 141 and the first metal patch 131 may be electrically connected through a metallized via on the dielectric layer 11, and the second metal sheet 142 and the second metal patch 132 may be electrically connected through a metallized via on the dielectric layer 11.

[0134] In some other embodiments, the capacitive structures 14 distributed on both sides of the dielectric layer 11 and the second metal layer 13 may also be electrically connected via a transmission line, which is not limited in this embodiment.

[0135] In one embodiment, Fig.21 The exploded view of the frequency selective surface unit 10 provided in another embodiment of the present application is shown in FIG. Fig.21 The frequency selective surface unit 10 further includes a third metal patch 16, which is located on the same side of the dielectric layer 11 as the second metal layer 13, and there is a gap between the third metal patch 16 and the second metal layer 13, and the third metal patch 16 is electrically connected to the first metal layer 12. Since there is no dielectric plate between the second metal layer 13 and the third metal patch 16, the electromagnetic coupling effect between the second metal layer 13 and the third metal patch 16 can be improved.

[0136] Among them, refer to Fig.21 , a second metal connection structure 113 is provided on the dielectric layer 11, and the third metal patch 16 is electrically connected to the first metal layer 12 through the second metal connection structure 113. The second metal connection structure 113 does not occupy additional space of the frequency selective surface unit 10, and can ensure the reliability of the connection between the first metal layer 12 and the third metal patch 16. In addition, in some other embodiments, the first metal layer 12 and the third metal patch 16 can also be electrically connected through a transmission line, which is not limited in this embodiment.

[0137] The second metal layer 13 and the third metal patch 16 may be located in the same plane. Of course, in some other embodiments, the second metal layer 13 and the third metal patch 16 may also be located in different planes.

[0138] In one embodiment, referring to Figure 4 , the first metal patch 131 and the second metal patch 132 are located in the same plane in a thickness direction perpendicular to the dielectric layer 11. The first metal patch 131 and the second metal patch 132 can be attached to one surface of the same dielectric layer 11, that is, the first metal patch 131 and the second metal patch 132 are located on the same plane. This embodiment can be applied to the scenario of using a single-layer dielectric plate with uniform thickness, and it is also convenient for the overall arrangement of the second metal layer 13.

[0139] In one embodiment, the first metal patch 131 and the second metal patch 132 may also be located in different planes in the thickness direction perpendicular to the dielectric layer 11, and the first metal patch 131 and the second metal patch 132 may also be coupled to generate a magnetic response. This embodiment may be applicable to scenarios with multiple dielectric layers 11 or scenarios with uneven thickness of the dielectric layer 11.

[0140] For example, Fig. 22 The exploded view of the frequency selective surface unit 10 provided in another embodiment of the present application is shown in FIG. Fig. 22 In this embodiment, the dielectric layer 11 has two layers, and the first metal layer 12, one dielectric layer 11, the first metal patch 131, another dielectric layer 11, and the second metal patch 132 are stacked in sequence, that is, the first metal patch 131 and the second metal patch 132 are respectively located on both sides of one of the dielectric layers 11, and are not in the same plane. The first metal patch 131 and the second metal patch 132 in this embodiment can also generate magnetic response. Of course, in some other embodiments, more than three dielectric layers 11 can also be provided, and the first metal patch 131 and the second metal patch 132 can also be located on both sides of one of the dielectric layers 11, or be provided in different dielectric layers 11, so that the first metal patch 131 and the second metal patch 132 are located in different planes, so that the coupling effect between the first metal patch 131 and the second metal patch 132 can be adjusted in different application scenarios.

[0141] The above are only preferred embodiments of the present application and are not intended to limit the present application. For those skilled in the art, the present application may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A frequency selective surface unit, characterized in that: include: A dielectric layer, wherein the dielectric layer is provided with a mounting portion, and the mounting portion is used to cross-connect two of the frequency selective surface units; A first metal layer, disposed on one side of the dielectric layer; The second metal layer is arranged on the side of the dielectric layer away from the first metal layer, and a capacitive structure or device is arranged on the second metal layer.

2. The frequency selective surface unit according to claim 1, characterized in that Along the first direction of the dielectric layer, at least one side edge of the dielectric layer is provided with a notch, along the second direction of the dielectric layer, one end of the notch passes through one side edge of the dielectric layer, and the other end of the notch forms a step surface, and the notch is the mounting portion; the first direction is perpendicular to the second direction.

3. The frequency selective surface unit according to claim 1 or 2, characterized in that: Along a first direction of the dielectric layer, a first gap is provided between the second metal layer and an edge of the dielectric layer.

4. The frequency selective surface unit according to any one of claims 1 to 3, characterized in that: Along a first direction of the dielectric layer, the first metal layer extends to an edge of the dielectric layer, so as to be electrically connected to the first metal layer on another adjacent frequency selective surface unit.

5. The frequency selective surface unit according to any one of claims 1 to 4, characterized in that: The first metal layer includes a first segment, a second segment and a third segment, one end of the second segment is connected to the first segment, the other end of the second segment is connected to the third segment, the first segment and the third segment extend along a first direction of the dielectric layer, and the third segment extends away from one end of the second segment to an edge of the dielectric layer, and the second segment extends along a second direction of the dielectric layer; The first section is located at the center of the dielectric layer, and there is a gap between the third section and the mounting portion.

6. The frequency selective surface unit according to any one of claims 1 to 5, characterized in that: The second metal layer includes a first metal patch and a second metal patch. A second gap is provided between the first metal patch and the second metal patch. The first metal patch and the second metal patch form the capacitive structure at the second gap.

7. The frequency selective surface unit according to claim 6, characterized in that: At least one of the first metal patch and the second metal patch is provided with a protruding portion, and the other is provided with a recessed portion, the protruding portion extends into the recessed portion, and there is the second gap between the protruding portion and the inner wall of the recessed portion, and the protruding portion and the recessed portion cooperate to form the capacitive structure.

8. The frequency selective surface unit according to claim 6, characterized in that: The first metal patch and the second metal patch are located in the same plane in a direction perpendicular to the thickness of the dielectric layer.

9. The frequency selective surface unit according to claim 6, characterized in that: The first metal patch and the second metal patch are located in different planes in a direction perpendicular to the thickness of the dielectric layer.

10. The frequency selective surface unit according to claim 9, characterized in that: The dielectric layer has multiple layers, and the first metal patch and the second metal patch are arranged on both sides of a portion of the dielectric layer in a thickness direction.

11. The frequency selective surface unit according to any one of claims 1 to 5, characterized in that: The capacitive structure or device and the second metal layer are located on the same side of the dielectric layer.

12. The frequency selective surface unit according to any one of claims 1 to 5, characterized in that: The capacitive structure or device and the second metal layer are respectively located on two sides of the dielectric layer, and the capacitive structure or device is electrically connected to the second metal layer.

13. The frequency selective surface unit according to claim 9, characterized in that: A first metal connection structure is disposed on the dielectric layer, and the capacitive structure or device is electrically connected to the second metal layer through the first metal connection structure.

14. The frequency selective surface unit according to any one of claims 1 to 5, characterized in that: The frequency selective surface unit further includes a third metal patch, which is located on the same side of the dielectric layer as the second metal layer, with a gap between the third metal patch and the second metal layer, and is electrically connected to the first metal layer.

15. The frequency selective surface unit according to claim 14, characterized in that: A second metal connection structure is disposed on the dielectric layer, and the third metal patch is electrically connected to the first metal layer through the second metal connection structure.

16. A frequency selective surface device, characterized in that: The method comprises a plurality of frequency selective surface units according to any one of claims 1 to 15, wherein the plurality of frequency selective surface units comprise a plurality of first frequency selective surface units and a plurality of second frequency selective surface units, the plurality of the first frequency selective surface units are arranged in an array in a third direction, the plurality of the second frequency selective surface units are arranged in an array in a fourth direction, and the first frequency selective surface units and the second frequency selective surface units are cross-connected.

17. The frequency selective surface device according to claim 16, characterized in that: The first frequency selective surface unit and the second frequency selective surface unit are an integrally formed structure.

18. The frequency selective surface device according to claim 16, characterized in that The dielectric layers of two adjacent first frequency selective surface units are connected so that a first slot is formed between the mounting parts at the connection of the two adjacent dielectric layers; The dielectric layers of two adjacent second frequency selective surface units are connected so that a second slot is formed between the mounting parts at the connection of the two adjacent dielectric layers, and the step surface of the second slot contacts and limits the step surface of the first slot.

19. The frequency selective surface device according to claim 18, characterized in that The dielectric layers of the plurality of first frequency selective surface units are an integral structure formed in one piece, and the dielectric layers of the plurality of second frequency selective surface units are an integral structure formed in one piece; The first card slot and the second card slot are processed and formed on the integrally formed medium layer.

20. The frequency selective surface device according to claim 18, characterized in that The first metal layers of the plurality of first frequency selective surface units are an integral structure formed in one piece, and the first metal layers of the plurality of second frequency selective surface units are an integral structure formed in one piece.

21. An antenna system, characterized in that: A frequency selective surface device comprising any one of claims 1-15 or a frequency selective surface device comprising any one of claims 16-20.

22. A communication device, characterized in that: The method comprises the frequency selective surface device according to any one of claims 1 to 15 or the frequency selective surface device according to any one of claims 16 to 20.

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