Transparent transmission unit, array and preparation method thereof based on Huygens metasurface

Abstract

The present invention discloses a transparent transmission unit based on Huygens metasurface, an array and a preparation method thereof, wherein the unit includes an intermediate dielectric layer, a first metal layer and a second metal layer. The array includes a plurality of transparent transmission units of Huygens metasurface arranged in a rectangular arrangement. The method includes determining the phase distribution of the Huygens metasurface unit according to the generalized Snell's law, adjusting the parameters of the double arc structure, and obtaining the double arc structure parameters; preparing a metal layer according to the structural parameters and etching it on the surface of a PET layer; positioning the target on the PET layer, and pasting the PET layer etched with the metal layer on the glass through an optically transparent adhesive to prepare a transparent transmission unit. The embodiment of the present invention can achieve high transmittance of electromagnetic waves and is easy to be deployed on existing windows, and enhances the wireless signal reception range in a specific area. As a transparent transmission unit, an array and a preparation method thereof based on Huygens metasurface, the present invention can be widely used in the field of electromagnetic metasurface technology.

Description

Technical Field

[0001] The present invention relates to the technical field of electromagnetic supersurfaces, and in particular to a transparent transmission unit and an array based on a Huygens supersurface and a preparation method thereof. Background Art

[0002] The metasurface is composed of periodically arranged artificial subwavelength unit structures, which can flexibly manipulate electromagnetic waves. In related technologies, the manufacture of metasurfaces requires the use of opaque printed circuit boards and copper patches. This design is difficult to integrate into urban environments or indoor layouts, destroys the overall aesthetics, limits the deployment location of the metasurface, and cannot be applied to glass windows in particular. In order to manufacture transparent metasurfaces, transparent conductive materials are required. However, transparent conductive materials usually sacrifice some of their conductive properties in exchange for high transparency, so it is difficult to achieve a transparent metasurface with both high transmittance and low electromagnetic wave loss.

[0003] Metasurfaces are divided into reflective and transmissive types. Reflective metasurfaces can achieve low electromagnetic wave loss and 360° phase control through a single-layer structure. However, transmissive metasurfaces usually require multi-layer structures to achieve 360° transmission phase control, which increases the difficulty of miniaturization and processing. Especially for transparent metasurfaces, multi-layer structures will significantly reduce the transmittance and are difficult to deploy on existing windows.

[0004] Huygens metasurfaces have attracted widespread attention due to their ability to simultaneously generate electric dipoles and magnetic dipoles and their ability to regulate electromagnetic waves. There are two common Huygens metasurface unit structures today: one is a wire-ring structure that directly uses metal wire patches as electric dipoles and metal rings as magnetic dipoles. This structure requires the medium to be cut and stacked together in a "fence-like" manner, making it difficult to deploy on existing windows; the other is a multi-layer stacking structure, and the stacking of multi-layer structures will cause the transmittance of the metasurface to drop sharply. Summary of the invention

[0005] In order to solve the above technical problems, the purpose of the present invention is to provide a transparent transmission unit, an array and a preparation method thereof based on Huygens metasurface, which can achieve high transmittance of electromagnetic waves and can be easily deployed on existing windows, and enhance the wireless signal reception range in specific areas.

[0006] The first technical solution adopted by the present invention is: a transparent transmission unit based on a Huygens metasurface, comprising an intermediate dielectric layer, a first metal layer and a second metal layer, wherein the first metal layer is disposed on the upper surface of the intermediate dielectric layer, and the second metal layer is disposed on the lower surface of the intermediate dielectric layer, wherein:

[0007] The intermediate medium layer is used for the propagation of light and electromagnetic waves;

[0008] The first metal layer and the second metal layer are both double-arc structures, and the opening positions of the double-arc structure of the first metal layer and the double-arc structure of the second metal layer are antisymmetric to each other. The first metal layer and the second metal layer are used for modulating electromagnetic waves to generate surface excitation current to form Huygens resonance, so as to improve the electromagnetic wave transmittance of the transparent transmission unit.

[0009] Furthermore, the intermediate medium layer includes a first PET layer, a glass layer and a second PET layer, wherein the first PET layer is adhered to the upper surface of the glass layer by optically transparent adhesive, the first metal layer is etched on the surface of the first PET layer, and the second PET layer is adhered to the lower surface of the glass layer by optically transparent adhesive, and the second metal layer is etched on the surface of the second PET layer.

[0010] Furthermore, the thickness of the first PET layer and the second PET layer are both 50 μm, and the thickness of the glass layer is 5 mm.

[0011] Furthermore, the first metal layer and the second metal layer respectively generate a first surface excitation current and a second surface excitation current under the condition of y-polarized incident electromagnetic waves, and at this time, the surface of the first metal layer and the surface of the second metal layer generate strong electric dipole resonance, and when the first surface excitation current and the second surface excitation current are in opposite directions, a strong magnetic dipole resonance is generated between the first metal layer and the second metal layer, and through the interaction of the strong electric dipole resonance and the strong magnetic dipole resonance, the Huygens metasurface is excited to generate Huygens resonance, so that the transparent transmission unit obtains a phase control range of 290° when the transmission amplitude is higher than -3 dB.

[0012] The third technical solution adopted by the present invention is: a transparent transmission array based on a Huygens metasurface, comprising a plurality of transparent transmission units of the Huygens metasurface arranged in a rectangular arrangement.

[0013] The third technical solution adopted by the present invention is: a method for preparing a transparent transmission unit based on a Huygens metasurface, comprising the following steps:

[0014] Determine the unit phase distribution of the Huygens metasurface according to the generalized Snell's law;

[0015] The parameters of the double arc structure are adjusted according to the unit phase distribution of the Huygens metasurface to obtain the double arc structure parameters;

[0016] A metal layer is prepared according to the double arc structure parameters and etched on the surface of the PET layer;

[0017] The target on the PET layer is positioned, and the PET layer etched with the metal layer is adhered to the glass by optically transparent adhesive to prepare a transparent transmission unit.

[0018] Further, the step of determining the unit phase distribution of the Huygens metasurface according to the generalized Snell's law specifically includes:

[0019] Determine the refractive index on both sides of the Huygens metasurface unit, the wavelength of the incident electromagnetic wave, and the incident angle of the incident electromagnetic wave;

[0020] According to the refractive index of both sides of the Huygens metasurface unit, the wavelength of the incident electromagnetic wave and the incident angle of the incident electromagnetic wave, the transmission angle of the Huygens metasurface is determined, and the relationship between the incident angle and the transmission angle of the Huygens metasurface is obtained;

[0021] Based on the generalized Snell's law and the relationship between the incident angle and the transmission angle of the Huygens metasurface, the unit phase distribution of the Huygens metasurface is determined.

[0022] Furthermore, the double arc structural parameters include the angle of the outer arc, the angle of the inner arc, the transmission amplitude of the transparent transmission unit and the phase control range of the transparent transmission unit.

[0023] The transparent transmission unit, transparent transmission array and preparation method of the present invention have the following beneficial effects: the present invention uses a metal layer with a double arc structure as a patch material, and the opening positions of the double arc structures of the upper and lower metal layers are in an antisymmetric relationship with each other, and uses an upper and lower layer of antisymmetric metal patch design to generate a strong magnetic dipole resonance; at the same time, the upper and lower layers of metal patches can independently generate a strong electric dipole resonance, and through the interaction between the electric dipole resonance and the magnetic dipole resonance, the metasurface can excite Huygens resonance, thereby achieving high transmittance of electromagnetic waves and being easy to deploy on existing windows, and enhancing the wireless signal reception range in a specific area. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is a structural schematic diagram of a transparent transmission unit based on Huygens metasurface of the present invention;

[0025] Figure 2 It is a schematic diagram of the preparation process of the transparent transmission unit based on the Huygens metasurface of the present invention;

[0026] Figure 3 It is a schematic diagram of the surface current distribution of an optically transparent Huygens metasurface unit under the condition of y-polarized incident electromagnetic wave provided by a specific embodiment of the present invention;

[0027] Figure 4 is a schematic diagram of an S-parameter curve of a Huygens metasurface provided by a specific embodiment of the present invention;

[0028] Figure 5 is a schematic diagram of normalized surface electrical admittance and normalized surface magnetic impedance curves of a Huygens metasurface provided by a specific embodiment of the present invention;

[0029] Figure 6 is a schematic diagram of symmetrically distributing the super surface units provided by a specific embodiment of the present invention;

[0030] Figure 7 It is a schematic diagram of a test scenario and electric field result of a metasurface provided by a specific embodiment of the present invention;

[0031] Figure 8 is a schematic structural diagram of a transparent transmission array of a Huygens metasurface provided by a specific embodiment of the present invention;

[0032] Fig. 9 It is a schematic diagram of the communication performance improvement result of the transparent transmission unit of the present invention compared with ordinary glass under vertical incidence of electromagnetic waves provided by a specific embodiment of the present invention;

[0033] Fig.10 It is a schematic diagram of the communication performance improvement result of the transparent transmission unit of the present invention compared with ordinary glass under the condition of 45° incidence of electromagnetic waves provided by a specific embodiment of the present invention;

[0034] Fig.11 It is a schematic diagram of the signal strength test result of the transparent transmission unit provided in a specific embodiment of the present invention. DETAILED DESCRIPTION

[0035] The present invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments. The step numbers in the following embodiments are only provided for the convenience of explanation and description, and the order between the steps is not limited in any way. The execution order of each step in the embodiment can be adaptively adjusted according to the understanding of those skilled in the art.

[0036] With the rapid development of mobile communication network technology, the demand for user transmission rate has increased significantly, prompting people to use higher frequency electromagnetic waves for communication. However, electromagnetic waves in high frequency bands have large attenuation and are difficult to diffract through obstacles, resulting in many signal coverage holes in high frequency wireless communication networks. Metasurfaces, as a new way to control wireless channels, have the characteristics of low cost, low power consumption, and easy deployment. Transparent metasurfaces, with their high light transmittance, have a wider range of application scenarios, and have therefore attracted widespread attention from industry and academia.

[0037] Based on this, refer to Figure 1 The present invention provides a transparent transmission unit based on a Huygens metasurface, the unit comprising an intermediate dielectric layer, a first metal layer and a second metal layer, the upper surface of the intermediate dielectric layer is provided with the first metal layer, the lower surface of the intermediate dielectric layer is provided with the second metal layer, wherein:

[0038] The intermediate medium layer is used for the propagation of light and electromagnetic waves;

[0039] Specifically, the intermediate medium layer includes a first PET layer, a glass layer and a second PET layer, wherein the first PET layer is adhered to the upper surface of the glass layer by optically transparent adhesive, the first metal layer is etched on the surface of the first PET layer, and the second PET layer is adhered to the lower surface of the glass layer by optically transparent adhesive, and the second metal layer is etched on the surface of the second PET layer.

[0040] The thickness of the first PET layer and the second PET layer are both 50 μm, and the thickness of the glass layer is 5 mm.

[0041] The first metal layer and the second metal layer are both double-arc structures, and the opening positions of the double-arc structure of the first metal layer and the double-arc structure of the second metal layer are antisymmetric to each other. The first metal layer and the second metal layer are used for modulating electromagnetic waves to generate surface excitation current to form Huygens resonance, so as to improve the electromagnetic wave transmittance of the transparent transmission unit.

[0042] Specifically, the first metal layer and the second metal layer respectively generate a first surface excitation current and a second surface excitation current under the condition of y-polarized incident electromagnetic waves, and at this time, strong electric dipole resonance is generated on the surface of the first metal layer and the surface of the second metal layer. When the first surface excitation current and the second surface excitation current are in opposite directions, strong magnetic dipole resonance is generated between the first metal layer and the second metal layer. Through the interaction of the strong electric dipole resonance and the strong magnetic dipole resonance, the Huygens metasurface is excited to generate Huygens resonance, so that the transparent transmission unit obtains a phase control range of 290° when the transmission amplitude is higher than -3 dB.

[0043] In this embodiment, the high-transmittance Huygens metasurface unit includes a medium and metal layers located on the upper and lower surfaces of the medium. Both the upper and lower metal layers include double arc structures. The opening positions of the upper and lower double arc structures are antisymmetric, and the upper and lower patches partially overlap at the openings. By adjusting the arc lengths of the inner and outer arcs, the Huygens metasurface unit can achieve 290° phase control while keeping the transmission amplitude higher than -3dB.

[0044] In order to achieve high transmittance, the metal layer patch is made of metal grid, and the medium is polyethylene terephthalate (PET) and glass. During the preparation process, the metal grid patch needs to be etched on PET first, and then the PET is attached to the glass with optically transparent adhesive. The use of these materials and preparation methods makes it easy to deploy the metasurface on existing windows and has a transmittance of more than 80%.

[0045] When electromagnetic waves are irradiated on the metasurface, the surface currents of the upper and lower metal layers are stimulated. Since there is a phase difference between the surface currents of the upper and lower metal layers, the surface currents of the upper and lower metal layers will flow in the same direction and in the opposite direction respectively within one cycle. When the surface currents of the upper and lower metal layers are opposite, the upper and lower metal layers will produce equivalent current loops, thereby forming a magnetic dipole resonance. The patches of the upper and lower metal layers form electric dipole resonances respectively. The interaction between the electric dipole resonance and the magnetic dipole resonance stimulates the Huygens resonance, thereby achieving high transmittance of electromagnetic waves.

[0046] According to the generalized Snell's law, the proposed optically transparent metasurface can generate -45° and 45° transmitted electromagnetic waves respectively when the electromagnetic waves are incident vertically, so as to improve the wireless signal coverage in a specific area.

[0047] Further, the structural details of the transparent transmission unit provided in the embodiment of the present invention are described. In the embodiment of the present invention, the metal grid patch of the Huygens metasurface unit is first etched on PET, and then the PET is respectively attached to the upper and lower surfaces of the glass using optical transparent adhesive. The metal grid patch structures of the upper and lower layers both adopt a double arc structure, and the upper and lower layers of patches have antisymmetric structural characteristics. Figure 1 The figure is a schematic diagram of the Huygens metasurface structure disclosed in the present invention. The metasurface unit dielectric materials are glass and PET, and their thicknesses are H1=5 mm and H2=50μm respectively. The metasurface unit adopts a square structure with a side length of P=18 mm. The patch adopts a double arc structure, and the radii of the outer and inner arcs are R1=8.5 mm and R2=7 mm respectively. The distance between the two layers of arcs is G=0.5 mm, and the patch line width is W=1 mm. and For the above patch, we use a metal grid with a line width of 10μm, a spacing of 200μm, and a thickness of 2μm. The square resistance of the metal grid under these parameters is 0.24Ω / sq.

[0048] Figure 3 : This is the surface current distribution diagram of the optically transparent Huygens metasurface unit under the condition of y-polarized incident electromagnetic wave. It can be obtained that when the surface currents of the upper and lower layers of metal grid patches flow in opposite directions, the upper and lower layers of metal patches introduce equivalent electric dipoles with opposite electric dipole moment directions (along the y-axis direction). This electric dipole with opposite directions can generate an equivalent current ring between the upper and lower layers of circular arcs, that is, magnetic dipole resonance (along the x-axis direction). Therefore, the optically transparent Huygens metasurface unit proposed in the embodiment of the present invention generates mutually orthogonal electric dipole resonance and magnetic dipole resonance under the condition of y-polarized electromagnetic wave incidence, thereby generating Huygens resonance and achieving high electromagnetic wave transmittance.

[0049] In order to better demonstrate the characteristics of Huygens metasurface units, Figure 4 The S-parameter curve of the proposed Huygens metasurface is shown. As can be seen from the figure, Huygens resonance allows the proposed Huygens metasurface unit to obtain a phase control range of about 290° while ensuring high transmittance.

[0050] A transparent transmission array based on a Huygens metasurface includes a plurality of transparent transmission units of Huygens metasurfaces arranged in a rectangular manner.

[0051] Specifically, the transparent transmission array based on the Huygens metasurface includes 24×24 Huygens metasurface units polarized along the y-axis, and the arrangement is as follows: Figure 8 As shown, transmission beams along -45° and 45° are obtained respectively.

[0052] In summary, the embodiments of the present invention provide a Huygens metasurface unit with high optical transmittance. The generalized Snell's law can be used to generate two electromagnetic waves pointing at -45° and 45° respectively when the electromagnetic wave is incident vertically, so as to enhance the wireless signal coverage in a specific area. Due to the symmetry of passive devices, the proposed metasurface may generate vertically transmitted electromagnetic waves under the conditions of -45° or 45° incidence, which can enhance the wireless signal reception range in a specific area. The embodiments of the present invention have a high transmittance and ultra-thin single-layer dielectric structure, which is easy to process and deploy on existing windows, and can be effectively applied to beam deflection, electromagnetic stealth and other aspects.

[0053] Therefore, the transparent transmission unit based on the Huygens metasurface and the transparent transmission array based on the Huygens metasurface in the embodiments of the present invention have the following advantages over the prior art:

[0054] 1) Metal mesh is used as the patch material, and PET and glass are used as the medium. Through the structure of "patch-PET-glass-PET-patch", the metasurface proposed in the embodiment of the present invention has a light transmittance of more than 80% and is easy to deploy on existing windows.

[0055] 2) Use two layers of antisymmetric metal patches to generate strong magnetic dipole resonance; at the same time, the two layers of metal patches can independently generate strong electric dipole resonance. Through the interaction of electric dipole resonance and magnetic dipole resonance, the metasurface can stimulate Huygens resonance, thereby achieving high transmittance of electromagnetic waves. The metasurface unit can achieve 290° transmission phase control. And because the proposed design method does not require cutting or stacking of media, it is more conducive to deployment on existing glass.

[0056] 3) The embodiment of the present invention also discloses a beam steering metasurface designed using the high-transmittance Huygens metasurface unit, which can enhance the wireless signal coverage in a specific area.

[0057] Reference Figure 2 , a method for preparing a transparent transmission unit based on a Huygens metasurface comprises the following steps:

[0058] S100, determining the unit phase distribution of the Huygens metasurface according to the generalized Snell's law;

[0059] Specifically, the refractive index on both sides of the Huygens metasurface unit, the wavelength of the incident electromagnetic wave and the incident angle of the incident electromagnetic wave are determined; the transmission angle of the Huygens metasurface is determined according to the refractive index on both sides of the Huygens metasurface unit, the wavelength of the incident electromagnetic wave and the incident angle of the incident electromagnetic wave, and the relationship between the incident angle and the transmission angle of the Huygens metasurface is obtained; based on the generalized Snell's law, the unit phase distribution of the Huygens metasurface is determined according to the relationship between the incident angle and the transmission angle of the Huygens metasurface.

[0060] S200, adjusting the parameters of the double arc structure according to the unit phase distribution of the Huygens metasurface to obtain the double arc structure parameters;

[0061] The double arc structure parameters include the angle of the outer arc, the angle of the inner arc, the transmission amplitude of the transparent transmission unit and the phase control range of the transparent transmission unit.

[0062] S300, preparing a metal layer according to the double arc structure parameters and etching the metal layer on the surface of the PET layer;

[0063] S400, positioning the target on the PET layer, and pasting the PET layer etched with the metal layer on the glass by optically transparent adhesive to prepare a transparent transmission unit.

[0064] Specifically, for a given electromagnetic wave polarization direction, the electric dipole resonance and magnetic dipole resonance of the Huygens metasurface can be expressed by the normalized surface electrical admittance ( ) and the normalized surface magnetoresistance ( ) characterization, where is the free space wave impedance. Based on the above characterization method, the normalized surface electrical admittance, normalized surface magnetic impedance and transmission coefficient (T) and reflection coefficient (R) have the following relationship, and the expression is:

[0065] ;

[0066] ;

[0067] in, is the free space wave impedance, is the electrical surface admittance, is the magnetic surface impedance.

[0068] From the expressions of normalized surface electrical admittance and normalized surface magnetic impedance, it can be obtained that when the real part of the normalized surface electrical admittance and the normalized surface magnetic impedance is zero and the imaginary part is equal, the Huygens metasurface unit achieves full transmission characteristics. Figure 5 The normalized surface electrical admittance and normalized surface magnetoimpedance curves of the proposed Huygens metasurface are shown. Figure 4 and Figure 5 It can be obtained that when the frequency is 5.5 GHz and 6.7 GHz, the real part of the normalized surface electrical admittance and the normalized surface magnetic impedance of the Huygens metasurface is basically zero, and the imaginary part is equal, so high electromagnetic wave transmittance is achieved at these two frequency points. Since the two high transmittance frequency points are close to each other, an electromagnetic wave passband is formed near them, and the unit can achieve 290° phase coverage in this passband.

[0069] Based on the above metasurface unit structure, an embodiment of the present invention provides a beam deflection metasurface structure with an operating frequency band near the 5.9 GHz communication frequency band, and the transmission angles of the deflected beam are -45° and 45° respectively, and the calculation process is as follows;

[0070] Based on the generalized Snell's law, the angle of incidence and the angle of transmission are related as follows:

[0071] ;

[0072] in and are the transmission angle and the incident angle, is the wavelength of the incident electromagnetic wave. Since both sides of the metasurface are air, Characterize the refractive index on both sides of the metasurface, is the phase gradient of the designed metasurface, where P is the side length of the metasurface unit. When the incident wave is incident vertically on the metasurface, the incident angle , and the medium on both sides of the metasurface is air ( ) can get:

[0073] ;

[0074] From the above formula, we can get that when the phase difference between adjacent units is When About 45°. Figure 6 The method shown distributes the metasurface units symmetrically, and beams transmitted to -45° and 45° can be obtained. According to the above method, Table 1 gives the specific reference values ​​of the Huygens metasurface to achieve a 45° deflection of the transmission beam while maintaining a high transmittance (-3dB) standard, as shown in Table 1:

[0075] Table 1 Reference values ​​of double arc structure parameters

[0076]

[0077] Based on the above Huygens metasurface structure design and the adjacent unit phase design, the optically transparent transmission metasurface proposed in the present invention has a total of 24*24 units. Figure 7 The test scenario and electric field result diagram of the metasurface proposed in the present invention are given. It can be seen that when the electromagnetic wave is incident vertically, the transmitted beam basically propagates along the -45° and 45° directions. When the electromagnetic wave is incident at 45°, the transmitted electromagnetic wave basically verifies that the metasurface propagates in the vertical direction. In addition, the optically transparent metasurface achieves a transmittance of 82% in the visible light range.

[0078] Fig. 9 , Fig.10 and Fig.11 The proposed metasurface shows improved communication performance compared to ordinary glass. When the transmission power is 15dBm, the received signal strength at points B1, B4, C1, and C4 at approximately -45° and 45° increases by 11.55dB, 10.9 dB, 11.33 dB, and 10.28 dB, respectively. For points B1 and B4, at a transmission power of -5dBm, the symbol error rate (SER) is reduced by 80% and 85%, respectively.

[0079] The contents of the above method embodiments are all applicable to the present system embodiments. The functions specifically implemented by the present system embodiments are the same as those of the above method embodiments, and the beneficial effects achieved are also the same as those achieved by the above method embodiments.

[0080] The above is a specific description of the preferred implementation of the present invention, but the invention is not limited to the embodiments. Those skilled in the art may make various equivalent modifications or substitutions without violating the spirit of the present invention. These equivalent modifications or substitutions are all included in the scope defined by the claims of this application.

Claims

1. A transparent transmission unit based on Huygens metasurface, characterized in that: It comprises an intermediate dielectric layer, a first metal layer and a second metal layer, wherein the first metal layer is disposed on the upper surface of the intermediate dielectric layer and the second metal layer is disposed on the lower surface of the intermediate dielectric layer, wherein: The intermediate medium layer is used for the propagation of light and electromagnetic waves; The intermediate medium layer comprises a first PET layer, a glass layer and a second PET layer, wherein the first PET layer is attached to the upper surface of the glass layer by optically transparent adhesive, the first metal layer is etched on the surface of the first PET layer, the second PET layer is attached to the lower surface of the glass layer by optically transparent adhesive, and the second metal layer is etched on the surface of the second PET layer; The first metal layer and the second metal layer are both double-arc structures, and the opening positions of the double-arc structure of the first metal layer and the double-arc structure of the second metal layer are antisymmetric to each other. The first metal layer and the second metal layer are used for modulating electromagnetic waves to generate surface excitation current to form Huygens resonance, so as to improve the electromagnetic wave transmittance of the transparent transmission unit, wherein the first metal layer is prepared by a metal grid.

2. The transparent transmission unit based on the Huygens metasurface according to claim 1, characterized in that: The thickness of the first PET layer and the second PET layer are both 50 μm, and the thickness of the glass layer is 5 mm.

3. The transparent transmission unit based on Huygens metasurface according to claim 2, characterized in that: The first metal layer and the second metal layer respectively generate a first surface excitation current and a second surface excitation current under the condition of y-polarized incident electromagnetic waves. At this time, strong electric dipole resonance is generated on the surface of the first metal layer and the surface of the second metal layer. When the first surface excitation current and the second surface excitation current are in opposite directions, strong magnetic dipole resonance is generated between the first metal layer and the second metal layer. Through the interaction of the strong electric dipole resonance and the strong magnetic dipole resonance, the Huygens metasurface is excited to generate Huygens resonance, so that the transparent transmission unit obtains a phase control range of 290° when the transmission amplitude is higher than -3 dB.

4. A transparent transmission array based on Huygens metasurface, characterized in that: A transparent transmission unit based on the Huygens metasurface as claimed in claim 1 comprising a plurality of rectangularly arranged units.

5. A method for preparing a transparent transmission unit based on a Huygens metasurface according to claim 1, characterized in that: The following steps are involved: Determine the unit phase distribution of the Huygens metasurface according to the generalized Snell's law; The parameters of the double arc structure are adjusted according to the unit phase distribution of the Huygens metasurface to obtain the double arc structure parameters; A metal layer is prepared according to the double arc structure parameters and etched on the surface of the PET layer; The target on the PET layer is positioned, and the PET layer etched with the metal layer is adhered to the glass by optically transparent adhesive to prepare a transparent transmission unit.

6. The method for preparing a transparent transmission unit based on a Huygens metasurface according to claim 5, characterized in that: The step of determining the unit phase distribution of the Huygens metasurface according to the generalized Snell's law specifically includes: Determine the refractive index on both sides of the Huygens metasurface unit, the wavelength of the incident electromagnetic wave, and the incident angle of the incident electromagnetic wave; According to the refractive index of both sides of the Huygens metasurface unit, the wavelength of the incident electromagnetic wave and the incident angle of the incident electromagnetic wave, the transmission angle of the Huygens metasurface is determined, and the relationship between the incident angle and the transmission angle of the Huygens metasurface is obtained; Based on the generalized Snell's law and the relationship between the incident angle and the transmission angle of the Huygens metasurface, the unit phase distribution of the Huygens metasurface is determined.

7. The method for preparing a transparent transmission unit based on a Huygens metasurface according to claim 6, characterized in that: The double arc structural parameters include the angle of the outer arc, the angle of the inner arc, the transmission amplitude of the transparent transmission unit and the phase control range of the transparent transmission unit.

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