Double-layer complementary frequency selective surface with multi-band communication signal anti-reflection function

Abstract

The invention provides a double-layer complementary frequency selective surface with a multi-band communication signal anti-reflection function. The double-layer complementary frequency selective surface comprises a first metal coating surface and a second metal coating surface which are arranged in sequence, wherein the surface of the first metal coating is provided with a first frequency selective surface; the surface of the second metal coating is provided with a second frequency selective surface; the pattern of the first frequency selective surface and the pattern of the second frequency selective surface are complementary patterns. According to the application, high transmittance of an electromagnetic signal in a target frequency band can be realized by arranging the frequency selective surface with the double-layer complementary structure; the frequency selective surface based on double-layer complementation realizes certain large-angle incidence and polarization stability. The pattern of the first frequency selective surface and the pattern of the second frequency selective surface are complementary patterns, so that the frequency selective surface with the double-layer complementary structure can realize high transmittance to electromagnetic waves of a target frequency band on the premise of keeping the original single-layer metal coating function (such as low radiation and power generation) as far as possible.

Description

Technical Field

[0001] This application belongs to the field of wireless communication technologies. More specifically, it relates to a double-layer complementary frequency selective surface with the function of enhancing the penetration of multi-band communication signals. Background Art

[0002] With the emphasis on sustainable development and the progress of industrial technologies, low-emissivity building glass, power generation glass, and low-emissivity automotive laminated glass are widely used. Low-emissivity building glass reduces the heat transfer between indoors and outdoors by means of coating, contributing to building energy conservation; power generation glass can efficiently convert solar energy into electrical energy, being green and environmentally friendly; low-emissivity automotive laminated glass can reduce the heat radiation exchange inside the vehicle, improving the energy utilization efficiency of the vehicle.

[0003] However, with the rapid development of the Internet of Things technology and the wide application of high-frequency signals such as 5G, the problem of signal attenuation by the metal coatings in low-emissivity building glass, power generation glass, and low-emissivity automotive laminated glass has become increasingly prominent. The metal coating of low-emissivity building glass hinders the interaction of communication signals between indoors and outdoors, resulting in poor network connection of smart home devices with external base stations and other signals. The metal coating of low-emissivity automotive laminated glass causes the interruption or delay of vehicle networking signals, affecting functions such as intelligent driving. The wavelength of 5G high-frequency signals is relatively short, and it is easy to be reflected, scattered, and absorbed when encountering the metal coating, increasing the path loss of the signal, significantly attenuating the signal, and seriously affecting the communication quality.

[0004] Currently, in the prior art, improving the signal transmittance of the metal coating often damages the metal heat insulation coating, thereby causing losses to the original functions of the metal coating, such as low-emission and power generation functions. There is an urgent need for innovative technologies to break through this difficulty. Summary of the Invention

[0005] The purpose of the embodiments of this application is to provide a frequency selective surface with a double-layer complementary structure. Specifically, the original single-layer metal coating is transformed into a frequency selective surface with a double-layer complementary structure to solve the technical problem in the prior art that it is difficult to balance the loss of the original function of the metal coating and the signal transmittance.

[0006] To achieve the above purpose, the technical solution adopted in this application is: to provide a frequency selective surface with a double-layer complementary structure, including a first metal coating surface and a second metal coating surface; wherein, the first metal coating surface has a first frequency selective surface; the second metal coating surface has a second frequency selective surface; the pattern of the first frequency selective surface and the pattern of the second frequency selective surface are complementary graphics.

[0007] Further, the first frequency selective surface is of the aperture type or the patch type; the second frequency selective surface is of the aperture type or the patch type.

[0008] Further, the first frequency selective surface includes a plurality of first structural units distributed in an array; the second frequency selective surface includes a plurality of second structural units distributed in an array.

[0009] Further, the shape of the first structural unit is a centrally symmetric figure, including a circle, a hexagon, and a square; the shape of the second structural unit is also a centrally symmetric figure, including a circle, a hexagon, and a square.

[0010] As an alternative, the first structural unit is a hexagonal patch unit, and the side length d1 of the hexagonal patch unit ranges from 0.1 mm to 3 mm; the gap w1 between adjacent hexagonal patch units ranges from 1 μm to 1 mm; The second structural unit is a hexagonal bar unit, and the side length d2 of the hexagonal bar unit ranges from 0.1 mm to 3 mm; the line width w2 of the hexagonal bar unit ranges from 1 μm to 1 mm.

[0011] Further, in the hexagonal bar unit, a partition is provided at the midpoint of each side of the hexagon, and the width w3 of the partition ranges from 1 μm to 1 mm.

[0012] Further, when d1 = d2 and w1 = w2, the first frequency selective surface and the second frequency selective surface are complementary and equivalent to a single-layer metal coating; the partition is formed by etching, and the percentage of the area of the single-layer metal coating etched off in the total area of the single-layer metal coating satisfies the following relationship: 。

[0013] As another alternative, the first structural unit is a first square patch FSS unit, and the first square patch FSS unit has four regions of upper left, lower left, upper right, and lower right adjacent to each other; the first square patch FSS unit includes two first square patches, and the two first square patches are located in the lower left region and the upper right region respectively; The second structural unit is a second square patch FSS unit, and the second square patch FSS unit has four regions of upper left, lower left, upper right, and lower right adjacent to each other; the second square patch FSS unit includes two second square patches, and the two second square patches are located in the upper left region and the lower right region respectively.

[0014] Further, the side length a1 of the first square patch ranges from 100 μm to 1.5 mm; the side length a2 of the second square patch ranges from 100 μm to 1.5 mm.

[0015] Further, first etching regions are provided at four vertices of the first square patch; the shape of the first etching region is a quarter circle with the vertex of the first square patch as the center and r1 as the radius; Second etching regions are provided at four vertices of the second square patch; the shape of the second etching region is a quarter circle with the vertex of the second square patch as the center and r2 as the radius.

[0016] Further, when a1 = a2 and r1 = r2, the first square patch FSS unit and the second square patch FSS unit are complementary and equivalent to a single-layer metal coating; the percentage of the area of the first etching region and the second etching region in the total area of the single-layer metal coating satisfies the following relationship: 。

[0017] For the double-layer complementary frequency selective surface provided by this application with the function of enhancing the transmission of multi-band communication signals, the following enhanced transmission target frequency bands are included: Operator mobile 5G and 6G: China Mobile 5G, (n41) 2515 MHz to 2675 MHz China Telecom 5G, (n78) 3400 MHz to 3500 MHz China Unicom 5G, (n78) 3500 MHz to 3600 MHz China Telecom, China Unicom and China Radio and Television jointly own the (n77) frequency band of 3300 MHz to 3400 MHz The "Regulations on Radio Frequency Allocation" clearly states that the Ministry of Industry and Information Technology has taken the lead in globally allocating all or part of the 6 GHz (6425 - 7125 MHz) 6775 MHz frequency band for IMT (5G / 6G) systems, and new high-frequency bands such as the millimeter wave band of 24.75 - 27.5 GHz (n258) have been added.

[0018] The B1 frequency band of Beidou civilian navigation: 1561.098 MHz (1559.052 MHz to 1591.788 MHz).

[0019] Wifi: The 2.4 GHz frequency band (2.4 to 2.4835 GHz) can be used for radio communication systems such as broadband wireless access (including wireless local area networks), Bluetooth, and point-to-point transmission. The 5 GHz frequency band (5.15 to 5.85 GHz) can be used for radio communication systems such as broadband wireless access (including wireless local area networks), point-to-point transmission, and electronic toll collection without stopping (ETC).

[0020] In-vehicle communication: 5905-5925MHz frequency band (5915MHz). Application: Planned for direct communication of Internet of Vehicles (intelligent connected vehicles), supporting direct communication and information exchange between vehicles (V2V), vehicles and roads (V2I), and vehicles and people (V2P).

[0021] The beneficial effects of the double-layer complementary frequency selective surface with multi-band communication signal transmission enhancement function provided by the present application are: compared with the prior art, in the present application, by setting a frequency selective surface with a double-layer complementary structure, it is possible to achieve high transmittance of electromagnetic signals in the target frequency band; the designed frequency selective surface based on double-layer complementarity achieves certain large-angle incidence and polarization stability. By setting a first frequency selective surface and a second frequency selective surface with complementary structures, the function of the original single-layer metal coating can be retained as much as possible; the pattern of the first frequency selective surface and the pattern of the second frequency selective surface are complementary patterns, so that the frequency selective surface with a double-layer complementary structure can achieve high transmittance of electromagnetic waves in the target frequency band while retaining the functions of the original single-layer metal coating (such as low radiation and power generation) as much as possible. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0023] Figure 1 A schematic diagram of the structure of a hexagonal patch FSS unit with a multi-band communication signal anti-transmission function provided in an embodiment of the present application; Figure 2 A schematic diagram of the structure of a hexagonal strip FSS unit with a multi-band communication signal anti-transmission function provided in an embodiment of the present application; Figure 3 A top view of a hexagonal patch FSS unit and a hexagonal strip FSS unit in a double-layer complementary frequency selective surface with a multi-band communication signal anti-transmission function provided in an embodiment of the present application; Figure 4 Schematic diagram of the exploded structure of the low-radiation automotive laminated glass with multi-band communication signal anti-reflection function provided in an embodiment of the present application (hexagon); Figure 5 The s-parameter simulation results (hexagon) of the low-radiation automotive laminated glass with multi-band communication signal anti-reflection function provided in the embodiment of the present application; Figure 6 A schematic diagram of the structure of a second square patch FSS unit with a multi-band communication signal anti-transmission function provided in an embodiment of the present application; Figure 7 Schematic diagram of the first square patch FSS unit structure with the function of enhancing the penetration of multi-band communication signals provided by the embodiment of the present application; Figure 8 Explosion structure diagram (square) of the low-radiation automotive laminated glass with the function of enhancing the penetration of multi-band communication signals provided by the embodiment of the present application; Figure 9 S-parameter simulation results (square) of the low-radiation automotive laminated glass with the function of enhancing the penetration of multi-band communication signals provided by the embodiment of the present application.

[0024] Among them, the reference numerals in the figure are as follows: 100 - The first glass layer; 200 - The surface of the first metal coating; 201 - Hexagonal patch unit; 202 - The first square patch; 221 - The first etching area; 300 - PVB layer; 400 - The surface of the second metal coating; 401 - Hexagonal strip unit; 411 - Partition; 402 - The second square patch; 421 - The second etching area; 500 - The second glass layer. Detailed implementation manners

[0025] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present application clearer, the present application will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0026] It should be noted that when an element is referred to as being "fixed to" or "disposed on" another element, it can be directly on the other element or indirectly on the other element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or indirectly connected to the other element.

[0027] It should be understood that the orientation or positional relationship indicated by the terms "length", "width", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. is based on the orientation or positional relationship shown in the accompanying drawings, and is only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation to the present application.

[0028] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, features defined with "first" and "second" may explicitly or implicitly include one or more of such features. In the description of this application, "a plurality of" means two or more, unless otherwise specifically defined.

[0029] In this embodiment, the communication in the scenario of low-emissivity automotive glass is taken as an example for illustration.

[0030] Please refer to Figure 4 and Figure 8 for a description of the low-emissivity automotive laminated glass with the function of enhancing the transmission of multi-band communication signals provided by the embodiments of this application. The low-emissivity automotive laminated glass with the function of enhancing the transmission of multi-band communication signals includes a first glass layer 100, a first metal coating surface 200, a PVB layer 300, a second metal coating surface 400, and a second glass layer 500 arranged in sequence; wherein, the first metal coating surface 200 has a first frequency selective surface; the second metal coating surface 400 has a second frequency selective surface; the pattern of the first frequency selective surface and the pattern of the second frequency selective surface are complementary patterns.

[0031] Compared with the prior art, for the low-emissivity automotive laminated glass with the function of enhancing the transmission of multi-band communication signals provided by this application, in the embodiments of this application, by providing a first heat insulation layer and a second heat insulation layer, the heat insulation effect of the low-emissivity automotive laminated glass can be improved; by providing a first frequency selective surface and a second frequency selective surface, a high transmittance of electromagnetic signals in the target frequency band can be achieved; the pattern of the first frequency selective surface and the pattern of the second frequency selective surface are complementary patterns, so that the low-emissivity automotive laminated glass can achieve a high transmittance of electromagnetic waves in the target frequency band on the premise of retaining the heat insulation effect of the low-emissivity automotive laminated glass.

[0032] In this embodiment, both the first glass layer 100 and the second glass layer 500 are made of white glass or ultra-white glass, which has high visible light transparency and durability, and can effectively ensure the clarity and safety of the driving vision. At the same time, the selection of white glass or ultra-white glass can further enhance the overall aesthetic appearance of the laminated glass, meeting the pursuit of modern automotive exterior design. In addition, the thickness and strength of the first glass layer 100 and the second glass layer 500 are carefully designed to ensure that the laminated glass has sufficient strength and toughness when subjected to external force impacts, thereby protecting the safety of the passengers in the vehicle.

[0033] In this embodiment, the PVB layer 300 uses a PVB film, that is, a polyvinyl butyral film, which has good toughness and adhesion and can firmly bond the first glass layer 100 and the second glass layer 500 together to form an integral body. At the same time, the PVB film also has certain sound insulation and heat insulation effects, which can further improve the performance of the automotive laminated glass. When encountering external impact, the PVB film can effectively absorb and disperse the impact energy, prevent the glass fragments from splashing, and thus protect the safety of the passengers in the vehicle.

[0034] In this embodiment, transparent metal heat insulation materials are used on both the first metal coating surface 200 and the second metal coating surface 400. These materials are composed of multiple layers of metals and metal oxides deposited on a dielectric substrate and have a low emissivity and good heat insulation. Their main function is to reflect infrared radiation and prevent heat from entering the vehicle, thereby reducing the air conditioning energy consumption and improving the energy efficiency of the vehicle.

[0035] It can be understood that since the internal metal layers of the first metal coating surface 200 and the second metal coating surface 400 can both reflect infrared radiation and shield electromagnetic waves, the inevitably large number of stacked highly conductive metal layers will attenuate the electromagnetic signals in the communication frequency band. Therefore, this application is provided with a first frequency selective surface and a second frequency selective surface. The first frequency selective surface is formed by laser etching the first metal coating surface 200 and can play a role in signal enhancement. The second frequency selective surface is formed by laser etching the second metal coating surface 400 and can also play a role in signal enhancement.

[0036] It can be understood that a frequency selective surface (FSS) is a two-dimensional periodic structure, usually composed of metal patches or aperture units arranged on a dielectric substrate according to a certain pattern. When an electromagnetic signal reaches the FSS, it triggers the resonance effect of the FSS, thereby enhancing the transmission of the electromagnetic wave and reducing the attenuation of the electromagnetic signal. In this application, the first frequency selective surface and the second frequency selective surface are respectively arranged on the first metal coating surface 200 and the second metal coating surface 400. Through the carefully designed patterns and arrangements, they can achieve a high transmittance of electromagnetic waves in the target frequency band while retaining the heat insulation effect.

[0037] In an embodiment of this application, the first frequency selective surface is of the aperture type or the patch type; the second frequency selective surface is of the aperture type or the patch type.

[0038] Specifically, when the first frequency selective surface is of the aperture type, a series of regularly arranged apertures are formed on the surface 200 of the first metal coating. These apertures can allow electromagnetic waves of a specific frequency to penetrate while blocking electromagnetic waves of other frequencies, thereby achieving the effect of signal antireflection. When the first frequency selective surface is of the patch type, a series of metal patches are formed on the surface 200 of the first metal coating. These patches can also trigger the resonance effect of the FSS and enhance the transmission of electromagnetic waves of a specific frequency. For the second frequency selective surface, the design principle of its aperture type or patch type is the same as that of the first frequency selective surface, except that the targeted frequency band may be different to meet the requirements of signal antireflection for communication signals in different frequency bands.

[0039] In an embodiment of the present application, the first frequency selective surface includes a plurality of first structural units distributed in an array; the second frequency selective surface includes a plurality of second structural units distributed in an array.

[0040] In this embodiment, each first structural unit and second structural unit is a carefully designed micro-structure aimed at interacting with electromagnetic waves in a specific frequency band. For the first frequency selective surface, its first structural units may adopt apertures or patches with different shapes, sizes and arrangements to achieve efficient transmission of electromagnetic waves in a certain specific frequency band. The design of these structural units fully considers factors such as the wavelength and polarization direction of electromagnetic waves to ensure that while retaining the heat insulation performance, the signal strength in the target frequency band is maximized.

[0041] The second structural units of the second frequency selective surface may be designed for another frequency band, and their shapes, sizes and arrangements may be different from those of the first structural units to meet the requirements of signal antireflection for communication signals in different frequency bands. Through such a design, the automotive laminated glass of the present application can achieve efficient signal transmission in multiple frequency bands, providing a strong guarantee for the normal operation of in-vehicle communication devices.

[0042] In an embodiment of the present application, the shapes of the first structural units include circles, hexagons and squares; the shapes of the second structural units include circles, hexagons and squares.

[0043] In this embodiment, the first structural units in the shapes of circles, hexagons, and squares are respectively arranged ingeniously on the first frequency selective surface to form regular or irregular patterns, which further enhance the interaction with electromagnetic waves in a specific frequency band. Similarly, the circular, hexagonal, and square second structural units on the second frequency selective surface are also carefully laid out to ensure that they can effectively enhance the signals for another frequency band. Through this combined design of structural units with multiple shapes and sizes, the automotive laminated glass of the present application can achieve efficient transmission of communication signals in a wider frequency band range, not only improving the performance of in-vehicle communication devices but also ensuring unobstructed communication during driving. In addition, this design also takes into account both aesthetics and practicality, making the automotive laminated glass more in line with the aesthetic requirements of modern vehicles while maintaining its original functions.

[0044] In an embodiment of the present application, please refer to Figure 4 and Figure 8 , the value range of the thickness h1 of the first glass layer 100 is 0.9 mm to 6 mm; the thickness of the first metal coating surface 200 is h2; the value range of the thickness h3 of the PVB layer 300 is 0.38 mm to 0.76 mm; the thickness of the second metal coating surface 400 is h4, and the value range of the thickness h5 of the second glass layer 500 is 0.9 mm to 6 mm.

[0045] In this embodiment, by precisely controlling the thicknesses of the first glass layer 100, the PVB layer 300, and the second glass layer 500, we further optimize the overall performance and signal transmission efficiency of the automotive laminated glass. Specifically, as the outer layer, the selection of the thickness h1 of the first glass layer 100 not only concerns the strength and impact resistance of the glass but also affects the propagation characteristics of electromagnetic waves in it. Similarly, as the interlayer material, the precise regulation of the thickness h3 of the PVB layer 300 is crucial for maintaining the integrity of the glass and the signal enhancement effect. And the second glass layer 500, as the layer directly in contact with the in-vehicle environment, the selection of its thickness h5 takes into account both safety and the quality of signal transmission. This fine regulation of the glass layer thickness enables the automotive laminated glass of the present application to achieve more balanced and efficient signal transmission at different frequency bands, thus meeting the high requirements of modern vehicles for communication performance.

[0046] Embodiment 1 In an embodiment of the present application, please refer to Figure 1 and Figure 2, the first structural unit is a hexagonal patch unit 201, and the value range of the side length d1 of the hexagonal patch unit 201 is from 0.1 mm to 3 mm; the gap w1 between adjacent hexagonal patch units 201 has a value range of 1 μm to 1 mm; the second structural unit is a hexagonal strip unit 401, and the value range of the side length d2 of the hexagonal strip unit 401 is from 0.1 mm to 3 mm; the line width w2 of the hexagonal strip unit 401 has a value range of 1 μm to 1 mm.

[0047] In this embodiment, by reasonably designing the geometric parameters of the first structural unit and the second structural unit, an optimized antireflection effect for multi-band communication signals is achieved. Specifically, the selection of the side lengths d1 and d2 of the hexagonal patch unit 201 and the hexagonal strip unit 401 not only affects the resonant frequencies of their respective units, but also further broadens the frequency band range of signal antireflection through the coupling effect between them. At the same time, the precise control of the gap w1 between adjacent hexagonal patch units 201 and the line width w2 of the hexagonal strip unit 401 helps to reduce the loss of signals during transmission and improve the transmission efficiency of signals. This delicate structural design enables the automotive laminated glass of this application to achieve efficient and stable signal transmission in multiple frequency bands, thus meeting the high requirements of modern automobiles for communication performance.

[0048] In an embodiment of this application, please refer to Figure 2 and Figure 3 , in the hexagonal strip unit 401, a partition 411 is provided at the midpoint of each side of the hexagon, and the value range of the width w3 of the partition 411 is from 1 μm to 1 mm.

[0049] In this embodiment, the setting of the partition 411 further enhances the structural flexibility of the hexagonal strip unit 401, enabling it to more flexibly adjust the response to signals in different frequency bands. Specifically, the precise control of the width w3 of the partition 411 not only affects the resonant characteristics of the hexagonal strip unit 401 itself, but also optimizes the antireflection effect of signals in a specific frequency band by changing the electric field distribution inside the unit. This design enables the hexagonal strip unit 401 to achieve efficient signal transmission in a wider frequency band range, further improving the overall communication performance of the automotive laminated glass. At the same time, the presence of the partition 411 helps to reduce the crosstalk between units and ensure the stability and clarity of signal transmission. Therefore, the automotive laminated glass of this application realizes more precise regulation and optimization of multi-band communication signals by introducing the partition 411 structure.

[0050] In one embodiment of the present application, when d1 = d2 and w1 = w2, the surface 200 of the first metal coating and the surface 400 of the second metal coating are complementary, equivalent to a single-layer heat-insulating coating; the partition 411 is formed by etching, and the percentage of the area of the single-layer heat-insulating coating etched off in the total area of the single-layer heat-insulating coating satisfies the following relationship: .(1-1) In this embodiment, when the etching process satisfies the above relationship, the heat-insulating performance and the communication signal antireflection effect can be effectively balanced. Specifically, by precisely controlling the area of the single-layer heat-insulating coating etched off, the good heat-insulating performance of the automotive laminated glass is maintained, and the efficient transmission of communication signals within the required frequency band is ensured. This design strategy not only improves the functionality of the automotive laminated glass but also takes into account aesthetics and practicality. In addition, the partition 411 structure formed by the etching process further enhances the structural stability of the hexagonal bar unit 401, enabling it to maintain good performance in a complex and changing communication environment. Therefore, the automotive laminated glass of the present application realizes a double improvement in heat-insulating performance and communication signal antireflection effect by optimizing the etching process parameters.

[0051] In this embodiment, the surface 200 of the first metal coating can be deposited on one side of the first glass layer 100 by magnetron sputtering technology, and the surface 400 of the second metal coating can be deposited on one side of the second glass layer 500 by magnetron sputtering technology. The first glass layer 100 and the surface 200 of the first metal coating, as well as the second glass layer 500 and the surface 400 of the second metal coating, are combined into an integral low-emissivity automotive laminated glass via the PVB layer 300 by lamination technology. And through technologies such as laser etching or masking, the surface 200 of the first metal coating is transformed into an array composed of hexagonal patch units 201. The surface 400 of the second metal coating is transformed into an array composed of hexagonal bar units 401.

[0052] Specifically, the stacking sequence, thickness, and electromagnetic characteristic parameters of each component structure of the low-emissivity automotive laminated glass are shown in Table 1.

[0053] Table 1

[0054] In this embodiment, d1 = d2 = 451 μm, w1 = w2 = 50 μm, and w3 = 20 μm are set.

[0055] Using the simulation software CST Microwave Studio for simulation, the achieved multi-band communication signal antireflection effect is shown in Table 2. The results show that the designed frequency selective surface based on double-layer complementarity achieves a certain large-angle incidence and polarization stability.

[0056] Table 2

[0057] Table 3 summarizes the signal transmission results of the designed hexagonal double-layer complementary structure at multiple frequency bands such as operators, satellite navigation, and millimeter waves under normal incidence.

[0058] Table 3

[0059] To further analyze the multi-band signal enhancement effect of the low-emissivity automotive laminated glass with complementary first and second frequency selective surfaces, the S-parameter simulation results of the low-emissivity automotive laminated glass implemented in this application are compared with those of a bare glass without a heat-insulating coating and an automotive laminated glass with a heat-insulating coating having a single unetched FSS. The results are as Figure 5 shown.

[0060] Among them, the structure of the bare glass without a heat-insulating coating from outside the vehicle to inside the vehicle is: the first glass layer / PVB layer / the second glass layer; the automotive laminated glass with a heat-insulating coating having a single unetched FSS from outside the vehicle to inside the vehicle is: the first glass layer / PVB layer / heat-insulating coating / the second glass layer.

[0061] According to Figure 5 the simulation results, in the range of 0 to 35 GHz, for the automotive laminated glass with a heat-insulating coating having a single unetched FSS, its insertion loss is between -34.6 dB and -45.6 dB. For the low-emissivity automotive laminated glass implemented in this application, its insertion loss is between -0.73 dB and -5.2 dB. It can be seen that the insertion loss corresponding to the low-emissivity automotive laminated glass implemented in this application is improved by about -30 dB to -40 dB compared with that of the automotive laminated glass with a heat-insulating coating having a single unetched FSS.

[0062] According to Figure 5 the simulation results, under normal incidence, the difference in insertion loss between the low-emissivity automotive laminated glass implemented in this application and the bare glass without a heat-insulating coating is small in the range of 0 to 25 GHz. In the range of 0 to 40 GHz, for the bare glass without a heat-insulating coating, the insertion loss is approximately within -3 dB, and there is an insertion loss greater than -3 dB at 20 GHz to 25 GHz. While at 0 to 25 GHz, the insertion loss of the low-emissivity automotive laminated glass implemented in this application is within -4 dB. After 25 GHz, the insertion loss of the low-emissivity automotive laminated glass implemented in this application shows an increasing trend compared with that of the bare glass without a heat-insulating coating, but generally within -8 dB.

[0063] This indicates that when the frequency is from 0 to 25 GHz, the shielding effect of the low-radiation automotive laminated glass with complementary first and second frequency selective surfaces on communication signals has a small gap compared with the bare glass without heat-insulating coating. It can be seen that the complementary first and second frequency selective surfaces achieve a good signal transmission enhancement function.

[0064] The first metal coating surface 200 and the second metal coating surface 400 of this application respectively have complementary first and second frequency selective surfaces. In order to analyze the heat-insulating ability of the low-radiation automotive laminated glass implemented in this application, the first metal coating surface 200 and the second metal coating surface 400 can be equivalent to a single-layer heat-insulating coating. According to formula (1-1), the percentage of the area of the etched metal heat-insulating coating in the total area of the heat-insulating coating is about 0.5%, which is extremely low for the etching amount of the heat-insulating coating.

[0065] Therefore, it has almost no influence on the heat-insulating performance of the heat-insulating coating. This effectively solves the problem of converting the heat-insulating coating into a frequency selective surface to achieve signal transmission enhancement while losing the heat-insulating ability of the heat-insulating coating.

[0066] Embodiment 2 In an embodiment of this application, please refer to Figure 6 and Figure 7 , the first structural unit is the first square patch 202 unit, and the first square patch 202 unit has four regions of upper left, lower left, upper right, and lower right that are adjacent to each other in pairs; the first square patch 202 unit includes two first square patches 202, and the two first square patches 202 are respectively located in the lower left region and the upper right region; the second structural unit is the second square patch 402 unit, and the second square patch 402 unit has four regions of upper left, lower left, upper right, and lower right that are adjacent to each other in pairs; the second square patch 402 unit includes two second square patches 402, and the two second square patches 402 are respectively located in the upper left region and the lower right region.

[0067] In this embodiment, the two first square patches 202 of the first square patch 202 unit and the two second square patches 402 of the second square patch 402 unit are complementarily arranged in both the horizontal direction and the vertical direction to achieve a wider frequency response range and a better signal transmission enhancement effect.

[0068] Specifically, the two first square patches 202 of the first square patch 202 unit and the two second square patches 402 of the second square patch 402 unit are mirror-symmetrical in the horizontal direction and also mirror-symmetrical in the vertical direction. This complementary arrangement method enables the entire frequency selective surface to achieve better signal transmission characteristics in both the horizontal direction and the vertical direction, thereby further broadening the frequency response range.

[0069] For Figure 6 the first square patch 202 unit in Figure 6 , through a straight line parallel to the horizontal side and passing through the midpoint in the vertical direction, and a straight line parallel to the vertical side and passing through the midpoint in the horizontal direction, the first square patch 202 unit is equally divided into four small regions (i.e., the upper left, lower left, upper right, and lower right regions). These two straight lines are perpendicular to each other, and the intersection point is the geometric center of the first square patch 202 unit. In an embodiment of the present application, the value range of the side length a1 of the first square patch 202 is from 100 um to 1.5 mm; the value range of the side length a2 of the second square patch 402 is from 100 um to 1.5 mm.

[0070] In this embodiment, the side lengths of the first square patch 202 and the second square patch 402 are designed such that they can effectively operate in different frequency bands. The value ranges of the side lengths a1 and a2 enable these two square patches to provide a stable signal antireflection effect within a relatively wide frequency range. In addition, this side length design also takes into account the feasibility of the manufacturing process and cost - effectiveness, ensuring the practicality and market competitiveness of the product. During specific implementation, appropriate side length values can be selected within the given value ranges according to the actual application requirements and manufacturing process conditions to achieve the best signal antireflection effect.

[0071] In an embodiment of the present application, please refer to Figure 6 and Figure 7 , at the four vertices of the first square patch 202, there are first etching regions 221; the shape of the first etching regions 221 is a quarter - circle with the vertex of the first square patch 202 as the center and r1 as the radius; at the four vertices of the second square patch 402, there are second etching regions 421; the shape of the second etching regions 421 is a quarter - circle with the vertex of the second square patch 402 as the center and r2 as the radius.

[0072] In this embodiment, the settings of the first etching regions 221 and the second etching regions 421 further optimize the signal transmission characteristics of the frequency - selective surface. Through the etching process, the electromagnetic energy accumulation at the patch vertices is reduced, the signal reflection is lowered, thereby improving the signal antireflection effect. At the same time, the quarter - circle etching region design is not only aesthetically pleasing but also can effectively disperse electromagnetic waves, reduce interference, and ensure the stable transmission of signals in different frequency bands. During specific implementation, the values of r1 and r2 can be determined according to the actual application requirements and manufacturing process conditions to achieve the best signal transmission effect.

[0073] In one embodiment of the present application, when a1 = a2 and r1 = r2, the surface 200 of the first metal coating and the surface 400 of the second metal coating are complementary, equivalent to a single-layer heat-insulating coating; the percentage of the areas of the first etching region 221 and the second etching region 421 in the total area of the single-layer heat-insulating coating satisfies the following relationship: . (1 - 2) In this embodiment, by setting the conditions that a1 is equal to a2 and r1 is equal to r2, the complementarity between the surface 200 of the first metal coating and the surface 400 of the second metal coating is achieved. This design enables the two to be equivalent to a single and more efficient single-layer heat-insulating coating. This innovation not only simplifies the structure but also further improves the heat-insulating performance. In addition, the area ratios of the first etching region 221 and the second etching region 421 are determined through precise calculations, ensuring that the etching process optimizes the signal transmission characteristics without overly weakening the heat-insulating effect. This percentage relationship comprehensively considers the shape and size of the etching regions and the overall layout of the heat-insulating coating, which is the key to achieving the balance between enhanced transmission of multi-band communication signals and low-radiation heat insulation functions. In specific applications, this design can be flexibly adjusted according to actual needs to meet the specific requirements for communication signals and heat-insulating performance of different vehicle models and different regions.

[0074] In this embodiment, the surface 200 of the first metal coating can be deposited on one side of the first glass layer 100 through magnetron sputtering technology, and the surface 400 of the second metal coating can be deposited on one side of the second glass layer 500 through magnetron sputtering technology. The first glass layer 100 and the surface 200 of the first metal coating, as well as the second glass layer 500 and the surface 400 of the second metal coating, are combined into an integral low-radiation automotive laminated glass through lamination technology via the PVB layer 300. And through techniques such as laser etching or masking, the surface 200 of the first metal coating is transformed into an array composed of first square patch 202 units. The surface 400 of the second metal coating is transformed into an array composed of second square patch 402 units, as Figure 8 shown.

[0075] Specifically, the stacking sequence, thickness, and electromagnetic characteristic parameters of each component structure of the low-radiation automotive laminated glass can refer to Table 1 in Embodiment 1.

[0076] In this embodiment, a1 = 0.5 mm and r1 = 20 microns. To further analyze the multi-band signal enhancement effect of the low-radiation automotive laminated glass with complementary first frequency selective surface and second frequency selective surface, the S-parameter simulation results of the low-radiation automotive laminated glass implemented in this application are compared with those of a bare glass without a heat-insulating coating and an automotive laminated glass with a single-layer unetched FSS heat-insulating coating. The results are as Figure 9 shown.

[0077] Among them, the structure of the bare glass without the heat-insulating coating from the outside to the inside of the vehicle is: the first glass layer / PVB layer / the second glass layer; the automotive laminated glass with a single-layer unetched FSS heat-insulating coating from the outside to the inside of the vehicle is: the first glass layer / PVB layer / heat-insulating coating / the second glass layer.

[0078] From Figure 9 The simulation results show that the low-emissivity automotive laminated glass implemented in this application achieves almost the same insertion loss as the automotive laminated glass without the heat-insulating coating, and the insertion loss is improved by about -30 to -45 dB compared with the automotive laminated glass with a single-layer heat-insulating coating. It can be seen that the low-emissivity automotive laminated glass implemented in this application achieves a good multi-band signal transmission enhancement effect.

[0079] Table 4 summarizes the signal transmission results of the designed square double-layer complementary structure at multiple frequency bands such as operators, satellite navigation, and millimeter waves under normal incidence.

[0080] Table 4

[0081] The first metal coating surface 200 and the second metal coating surface 400 of this application respectively have complementary first frequency selective surfaces and second frequency selective surfaces. For the heat-insulating ability of the low-emissivity automotive laminated glass implemented in this application, the first metal coating surface 200 and the second metal coating surface 400 can be equivalent to a single-layer heat-insulating coating. It is calculated from formula (1-2) that the percentage of the area of the etched metal heat-insulating coating in the total area of the heat-insulating coating is about 0.5%, which is extremely low for the etching amount of the heat-insulating coating.

[0082] Therefore, it has almost no influence on the heat-insulating performance of the heat-insulating coating. This effectively solves the problem of converting the heat-insulating coating into a frequency selective surface to achieve the enhancement of communication signal transmission while losing the heat-insulating ability of the heat-insulating coating.

[0083] The above are only the preferred embodiments of this application and are not intended to limit this application. Any modifications, equivalent replacements, and improvements made within the spirit and principle of this application shall be included in the protection scope of this application.

Claims

1. A double-layer complementary frequency selective surface with the function of enhancing the transmission of multi-band communication signals, characterized in that, Comprising a first metal coating surface and a second metal coating surface arranged in sequence; Wherein, the first metal coating surface has a first frequency selective surface; the second metal coating surface has a second frequency selective surface; the pattern of the first frequency selective surface and the pattern of the second frequency selective surface are complementary patterns.

2. The double-layer complementary frequency selective surface with the function of enhancing the penetration of multi-band communication signals according to claim 1, wherein The first frequency selective surface is of the aperture type or the patch type; the second frequency selective surface is of the aperture type or the patch type.

3. The double-layer complementary frequency selective surface with the function of enhancing the transmission of multi-band communication signals according to claim 1, characterized in that, The first frequency selective surface includes a plurality of first structural units distributed in an array; the second frequency selective surface includes a plurality of second structural units distributed in an array.

4. The double-layer complementary frequency selective surface with the function of enhancing the transmission of multi-band communication signals according to claim 3, wherein, The shape of the first structural unit is a centrosymmetric figure, including a circle, a hexagon, and a square; the shape of the second structural unit is also a centrosymmetric figure, including a circle, a hexagon, and a square.

5. The double-layer complementary frequency selective surface with the function of enhancing the transmission of multi-band communication signals as described in claim 4, wherein, The first structural unit is a hexagonal patch unit, and the value range of the side length d1 of the hexagonal patch unit is from 0.1 mm to 3 mm; the value range of the gap w1 between adjacent hexagonal patch units is from 1 μm to 1 mm; The second structural unit is a hexagonal strip unit, and the value range of the side length d2 of the hexagonal strip unit is from 0.1 mm to 3 mm; the value range of the line width w2 of the hexagonal strip unit is from 1 μm to 1 mm.

6. The double-layer complementary frequency selective surface with the function of enhancing the transmission of multi-band communication signals according to claim 5, wherein In the hexagonal strip unit, partitions are provided at the midpoints of each side of the hexagon, and the value range of the width w3 of the partition is from 1 μm to 1 mm.

7. The double-layer complementary frequency selective surface with the function of enhancing the transmission of multi-band communication signals according to claim 6, wherein When d1 = d2 and w1 = w2, the first metal coating surface and the second metal coating surface are complementary and equivalent to a single-layer metal coating; the partition is formed by etching, and the percentage of the area of the single-layer metal coating etched away in the total area of the single-layer metal coating satisfies the following relationship: 。 8. The double-layer complementary frequency selective surface with the function of enhancing the transmission of multi-band communication signals according to claim 4, characterized in that, The first structural unit is a first square patch unit, and the first square patch unit has four regions of upper left, lower left, upper right, and lower right adjacent to each other; the first square patch unit includes two first square patches, and the two first square patches are respectively located in the lower left region and the upper right region; The second structural unit is a second square patch unit, and the second square patch unit has four regions of upper left, lower left, upper right, and lower right adjacent to each other; the second square patch unit includes two second square patches, and the two second square patches are respectively located in the upper left region and the lower right region.

9. The double-layer complementary frequency selective surface with the function of enhancing the transmission of multi-band communication signals as described in claim 8, wherein, The value range of the side length a1 of the first square patch is from 100 μm to 1.5 mm; the value range of the side length a2 of the second square patch is from 100 μm to 1.5 mm.

10. The double-layer complementary frequency selective surface with the function of enhancing the transmission of multi-band communication signals as described in claim 9, wherein The four vertices of the first square patch have first etching regions; the shape of the first etching region is a quarter circle with the vertex of the first square patch as the center and r1 as the radius; The four vertices of the second square patch have second etching regions; the shape of the second etching region is a quarter circle with the vertex of the second square patch as the center and r2 as the radius.

11. The double-layer complementary frequency selective surface with the function of enhancing the penetration of multi-band communication signals according to claim 10, characterized in that, When a1 = a2 and r1 = r2, the surfaces of the first metal coating and the second metal coating are complementary, equivalent to a single-layer metal coating; the percentages of the areas of the first etching region and the second etching region in the total area of the single-layer metal coating satisfy the following relationship: 。

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