Ultra-thin dual-polarized lens antenna based on double-layered huygens super surface

Abstract

The application discloses an ultra-thin dual-polarized lens antenna based on a double-layer Huygens super surface, and relates to the technical field of planar transmission array antennas. The ultra-thin dual-polarized lens antenna based on the double-layer Huygens super surface is provided with a horn antenna feed source module and a double-layer Huygens super surface module, wherein the double-layer Huygens super surface module is composed of a middle dielectric support layer and top and bottom metal patch layers with the same structure. By arranging unit cells of the double-layer Huygens super surface module according to a hyperbolic phase distribution, the super lens function is formed, the quasi-spherical wave emitted by the horn antenna feed source module is converted into a plane wave emitted in a single direction, and thus the directivity and radiation gain of electromagnetic waves are improved. The application has the advantages of dual-polarized response, ultra-thin thickness less than one-tenth of a wavelength, easy integration, high radiation gain and high aperture efficiency, and can be widely applied to the fields of millimeter wave communication systems, wireless power transmission and the like.

Description

Technical Field

[0001] This invention relates to the field of planar transmission array antenna technology, specifically to an ultrathin dual-polarized lens antenna based on a double-layer Huygens metasurface. Background Technology

[0002] Because metasurfaces can locally control the amplitude, phase, and polarization of scattered waves on subwavelength scale scattering elements, they are able to flexibly control wave propagation. Furthermore, due to their small size, low cost, and ease of manufacturing, they are widely used in the field of lens antenna design.

[0003] Traditional superlens designs require a transmittance phase shift range of 360°. While maintaining high transmittance, many current studies only consider the electric resonance in metasurfaces and neglect the role of magnetic resonance, resulting in low transparency and low phase shift coverage of transmitted waves, which greatly limits their ability to manipulate transmitted waves. Therefore, further development of Huygens metasurfaces was undertaken. The resonance of a Huygens metasurface consists of spatially varying electric and magnetic dipole resonances, which can be used to manipulate electromagnetic waves passing arbitrarily through the surface. Generally, there are two methods to construct Huygens metasurfaces: vertical metal ring resonators and multilayer cascaded surface unit structures. The former is difficult to fabricate due to its very complex structure, while the latter introduces more dielectric layers or air gaps, which increases the metasurface thickness and introduces more losses.

[0004] In recent years, many double-layer Huygens metasurface lens antenna structures have been proposed, such as the double-layer dual-polarization high-gain metalens disclosed in "MR Akram, C. He, and W. Zhu, 'Bi-layer metasurface based on Huygens' principle for high gain antenna applications,' Optics Express, vol. 28, no. 11, pp. 15844-15854, May 25 2020," but with low aperture efficiency; and "P. Wang, G. Huang, W. Wang, Y. Shao, C. Zhou, and H. Jin, 'Wideband transmit-array antenna design with dual-layer ultrathin Huygens' meta-surface for vehicular sensing and communication,' IEEE Trans. Veh. Technol., vol. 72, no. 6, pp. 7469-7479, Jun." The patent 2023 discloses a dual-layer broadband Huygens metasurface lens antenna with good antenna performance and an ultrathin thickness of less than one-tenth of the wavelength, but it only involves single polarization. For example, Chinese patent CN114336072A discloses a dual-layer transmission unit and array antenna based on Huygens metasurface, which includes a single-layer dielectric substrate and metal patches. The metal patch structure includes a metal open square ring and a central arm. The upper and lower surface metal patch units are rotationally symmetrical. The transmission array antenna of this invention has a high aperture efficiency, but the gain is not high in comparison. It only involves single polarization and the thickness is also greater than one-tenth of the wavelength. For example, Chinese patent CN117039445A discloses a terahertz antenna based on a dual-polarized Huygens metasurface lens unit. The transmission array antenna of this invention has dual-polarization response and high radiation gain, but the thickness is still greater than one-tenth of the wavelength. Summary of the Invention

[0005] The purpose of this invention is to overcome some of the shortcomings of the prior art and to provide an ultrathin dual-polarized lens antenna based on a double-layer Huygens metasurface, in order to further reduce the thickness of the metasurface and shrink the lens volume while ensuring good antenna performance.

[0006] To achieve the above objectives, the present invention provides the following solutions.

[0007] An ultrathin dual-polarized lens antenna based on a double-layer Huygens metasurface is disclosed. The antenna comprises a horn antenna feed module and a double-layer Huygens metasurface module. The double-layer Huygens metasurface module consists of an intermediate dielectric support layer and a top and bottom layer of metal patches with identical structures. By arranging the cell elements of the double-layer Huygens metasurface module according to a hyperbolic phase distribution, a superlens function is formed, which converts the quasi-spherical wave emitted by the horn antenna feed module into a plane wave emitted in a single direction, thereby improving the directivity and radiation gain of the electromagnetic wave.

[0008] The phase center of the horn antenna feed module of the Huygens metasurface-based ultrathin dual-polarized lens antenna is located at the focal point of the metasurface.

[0009] The intermediate dielectric support layer is made of dielectric materials such as Rogers material, polyethylene, polyimide, glass or silicon; the thickness of the intermediate dielectric support layer is less than one-tenth of the wavelength to ensure that effective support is achieved while meeting the requirements of ultra-thin antenna design.

[0010] The top and bottom layers are identical metal patch layers, located on the upper and lower surfaces of the intermediate dielectric support layer. Each cell substructure is composed of a combination of four L-shaped angular ring metal patches on the periphery and a grid-shaped metal patch in the center, exhibiting 90° rotational symmetry. The top and bottom layers of each cell are identical to ensure consistent electromagnetic performance.

[0011] The top and bottom layers, which have identical structures, are made of high-conductivity metals such as copper, silver, aluminum, or gold. Their excellent conductivity enhances the antenna's electromagnetic conversion efficiency.

[0012] The top and bottom layers are identical metal patch layers, with consistent dimensions for the double-layer metal patches within the same cell. The cell side length p, the corner ring side length s, the double-layer spacing d, the metal patch layer thickness h, the width w of the corner ring and grid-shaped metal patches, the grid-shaped metal patch length l, and the spacing t between the two metal strips of the grid-shaped metal patch are all fixed values ​​corresponding to the antenna's operating wavelength. The gap width g of the corner ring metal patch is an adjustable parameter of the Huygens resonance. The Huygens resonance of the metal patch layer ensures that each cell maintains a transmission coefficient amplitude of at least -2.3 dB, and the adjustment of the gap width g of the corner ring metal patch provides 360° full phase coverage. This significantly improves the flexibility and accuracy of the antenna's electromagnetic wave phase control.

[0013] The double-layer Huygens metasurface module is composed of multiple Huygens resonant cell elements. The N array has M and N sizes that ensure the metasurface lens side length D is not less than 10 times the wavelength. The Huygens resonant cell cells are arranged in the array according to the phase distribution required for the lens function, ensuring the effective realization of the metalens function.

[0014] The double-layer Huygens metasurface module is composed of Huygens resonant cell sub-arrangements, according to the following hyperbolic phase distribution formula:

[0015]

[0016] in, For operating frequency, The speed of light in a vacuum. These are the coordinates of the cell's location. This is represented as the phase at that coordinate. = 0, 1, 2,…, M; = 0, 1, 2, …, N. p is the side length of each cell, and F represents the focal length of the metasurface lens.

[0017] The focal length of the metasurface lens The ratio F / D to the side length D of the metasurface lens satisfies 0.7~1. Within this range, the antenna can achieve optimal radiation performance and focusing effect, effectively improving the overall performance of the antenna.

[0018] The principle of this invention is as follows:

[0019] When discontinuous fields and two spaces are separated by a metasurface, a magnetic field can be induced between two parallel currents on either side of the surface. These two currents act as both electric and magnetic dipoles, simultaneously inducing orthogonal currents and magnetocurrents. Their interaction excites Huygens resonances. Therefore, the unit cell structure consists of an electric resonance section and a magnetic resonance section, which respectively modulate the electric and magnetic fields. The electromagnetic properties of the Huygens metasurface can be expressed using its electric surface admittance. and magnetic surface impedance To describe them. They are related to the reflection coefficient. Transmission coefficient The relationship is:

[0020]

[0021]

[0022] in, For the wave impedance in free space, and Let be the normalized electrical surface admittance and magnetic surface impedance. When the real parts of the normalized electrical surface admittance and magnetic surface impedance are 0 and their imaginary parts are equal, Huygens resonance will be excited, and the metasurface will achieve high transmission performance.

[0023] In this invention, when the top or bottom metal patch layers generate surface currents in the same direction, an electric resonance mode is formed. When the top and bottom metal patch layers generate surface currents in opposite directions, a current loop with an electric displacement vector is formed, thereby inducing orthogonal magnetic fields and forming a magnetic resonance mode. When the induced orthogonal magnetic currents and currents interact to reach equilibrium, Huygens resonance is achieved, at which point a resonance peak with high transmission performance is induced.

[0024] Compared with existing technologies, the present invention has the following advantages: (1) The lens antenna has a dual polarization response, which improves polarization insensitivity and increases the signal channel. (2) The resonant frequency of electro-magnetic resonance can be adjusted by adjusting the gap width g of the metal patch of the cell sub-corner ring, and the transmission coefficient amplitude above -2.3 dB can be maintained and 360° phase coverage can be achieved. This precise phase and transmission coefficient control capability allows the antenna to accurately control and optimize electromagnetic waves according to different application requirements, providing strong support for achieving high-performance antenna functions. (3) The thickness of the lens antenna of the present invention is less than one-tenth of a wavelength, which is much thinner than that of traditional lenses. While maintaining high performance, the size of the antenna is greatly reduced, which is conducive to the integration of the antenna. The ultra-thin antenna structure is easier to integrate with other electronic components, meeting the needs of various portable devices and compact systems, and improving the overall performance and practicality of the device. (4) The lens antenna of the present invention greatly improves radiation gain, has high aperture efficiency, and can achieve high radiation gain within a certain frequency range. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of the ultrathin dual-polarized lens antenna based on a double-layer Huygens metasurface according to the present invention.

[0026] The numbers in the diagram are: 1-Double-layer Huygens metasurface module, 2-Horn antenna feed module, 3-Huygens resonator cell, 4-Top metal patch layer, 5-Intermediate dielectric support layer, 6-Bottom metal patch layer.

[0027] Figure 2 This is a schematic diagram of the structure of the Huygens resonant cell element of the present invention.

[0028] The numbers in the diagram are: 7 - top layer grid-shaped metal patch, 8 - top layer corner ring metal patch, 9 - bottom layer grid-shaped metal patch, 10 - bottom layer corner ring metal patch.

[0029] Figure 3This is a schematic diagram of the parameter names of the Huygens resonance cell element described in this invention.

[0030] Figure 4 This is a graph showing the amplitude and phase of the transmission coefficient of a Huygens resonant cell cell as a function of frequency, according to an embodiment of the present invention.

[0031] Figure 5 This is a graph showing the normalized electrical surface admittance and magnetic surface impedance of a Huygens resonant cell cell as a function of frequency, according to an embodiment of the present invention.

[0032] Figure 6 This is a surface current distribution diagram of the top and bottom metal patch layers when the Huygens resonant cell cell is operating at 25 GHz, according to an embodiment of the present invention.

[0033] Figure 7 This is a graph showing the amplitude and phase of the transmission coefficient of the Huygens resonant cell cell as a function of the gap width g of the angled ring metal patch, according to an embodiment of the present invention.

[0034] Figure 8 This is a theoretical phase distribution diagram of an ultrathin dual-polarized lens based on a double-layer Huygens metasurface according to an embodiment of the present invention.

[0035] Figure 9 This is an actual phase distribution diagram of an ultrathin dual-polarized lens based on a double-layer Huygens metasurface according to an embodiment of the present invention.

[0036] Figure 10 This is an error diagram showing the actual phase distribution versus the theoretical phase distribution of an ultrathin dual-polarized lens based on a double-layer Huygens metasurface, according to an embodiment of the present invention.

[0037] Figure 11 This is a three-dimensional radiation gain diagram of the ultrathin dual-polarized lens antenna based on a double-layer Huygens metasurface according to an embodiment of the present invention, operating at a center frequency of 25 GHz.

[0038] Figure 12 The graphs show the radiation gain of the ultrathin dual-polarized lens antenna based on a double-layer Huygens metasurface under x-polarized or y-polarized spherical wave excitation, and the radiation gain of the horn antenna feed source as a function of frequency, according to an embodiment of the present invention.

[0039] Figure 13 This is a graph showing the aperture efficiency of an ultrathin dual-polarized lens antenna based on a double-layer Huygens metasurface, as a function of frequency under x-polarized or y-polarized spherical wave excitation, according to an embodiment of the present invention. Detailed Implementation

[0040] To make the objectives, technical solutions, and advantages of this invention clearer, the following embodiments will be used in conjunction with the accompanying drawings to further illustrate the invention. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

[0041] like Figure 1 As shown in the schematic diagram of the ultrathin dual-polarized lens antenna based on a double-layer Huygens metasurface, the ultrathin dual-polarized lens antenna of this embodiment includes a double-layer Huygens metasurface module 1 and a horn antenna feed module 2. The double-layer Huygens metasurface module 1 is composed of multiple Huygens resonant cell elements 3, which are arranged from top to bottom as a top metal patch layer 4, an intermediate dielectric support layer 5, and a bottom metal patch layer 6. The phase center of the horn antenna feed module 2 is located at the focal point of the metalens. By arranging the cell elements of the double-layer Huygens metasurface module according to a hyperbolic phase distribution, a metalens function is formed. This double-layer Huygens metasurface can convert the quasi-spherical wave emitted by the horn antenna into a plane wave emitted in a single direction, thereby improving the radiation gain of the horn antenna.

[0042] Specifically, in the embodiments of the present invention, the top metal patch layer 4 and the bottom metal patch layer 6 are both composed of multiple Huygens resonance cell sub-structures 3. Each Huygens resonance cell sub-structure is composed of a combination of four L-shaped angular ring metal patches on the periphery and a grid-shaped metal patch in the center, exhibiting 90° rotational symmetry. Furthermore, the top and bottom structures of each cell sub-structure are completely identical.

[0043] Figure 2 The schematic diagram of the structure of the Huygens resonant cell of the present invention is shown. The top layer of the designed Huygens resonant cell consists of a grid-shaped metal patch 7 and a angular ring metal patch 8, and the bottom layer consists of a grid-shaped metal patch 9 and a angular ring metal patch 10. The top and bottom layers of each Huygens resonant cell are 90° rotationally symmetrical and have the same structural dimensions.

[0044] The top and bottom metal patch layers are made of high-conductivity metals such as copper, silver, aluminum, or gold. The intermediate dielectric support layer is made of dielectric materials such as Rogers material, polyethylene, polyimide, glass, or silicon. In an embodiment of the invention, the intermediate dielectric support layer is made of Rogers RT5880 material with a relative permittivity of 2.2. The top and bottom metal patch layers are made of copper with a conductivity of 5.8. 10 7 s / m has good conductivity, which helps improve antenna performance, while the cost is relatively controllable.

[0045] In the top and bottom metal patch layers, the structural dimensions of the double-layer metal patches in the same cell are consistent. The cell side length p, the corner ring side length s, the double-layer spacing d, the metal patch layer thickness h, the width w of the corner ring metal patch and the grid-shaped metal patch, the grid-shaped metal patch length l, and the spacing t between the two metal strips of the grid-shaped metal patch are all fixed values ​​corresponding to the antenna operating wavelength. The corner ring gap width g is an adjustable parameter of the Huygens resonance. The Huygens resonance of the metal patch layer provides each cell with a transmission coefficient amplitude of -2.3 dB or higher, and the adjustment of the corner ring gap width g provides 360° full phase coverage.

[0046] Figure 3 The parameter names of the Huygens resonant cell substructure described in this invention are shown. In a further embodiment, the side length of the Huygens resonant cell substructure is p = 4.8 mm, the double-layer spacing is d = 0.8 mm, the metal patch layer thickness is h = 0.018 mm, the side length of the angular ring is s = 4.6 mm, the width of the angular ring metal patch and the grid-shaped metal patch is w = 0.2 mm, the length of the grid-shaped metal patch is l = 3.05 mm, and the two metal strips of the grid-shaped metal patch are t = 0.4 mm.

[0047] Figure 4 The graphs showing the transmission coefficient amplitude and phase of the Huygens resonant cell element according to an embodiment of the present invention are presented as a function of frequency. It can be seen that within the frequency range of 25–31 GHz, the Huygens resonant cell element maintains a high transmission coefficient amplitude while covering a 360° phase range. This indicates that the design can achieve good phase modulation and high transmission performance over a wide frequency range, ensuring efficient antenna operation.

[0048] Figure 5 The graphs showing the normalized electrical surface admittance and magnetic surface impedance of the Huygens resonant cell sub-element as a function of frequency are presented according to an embodiment of the present invention. At frequencies of 25 GHz and 30.5 GHz, the real parts of the normalized electrical surface admittance and magnetic surface impedance are 0, while the imaginary parts are equal, representing Huygens resonance points. At these resonance points, the metasurface achieves high transmission performance, further validating the design principles and performance advantages of the present invention.

[0049] Figure 6 This invention illustrates the surface current distribution of the top and bottom metal patch layers when the Huygens resonant cell cell operates at 25 GHz, showing the top current J generated on the top corner ring metal patch and the grid-shaped metal patch. top The underlying current J generated on the top corner ring metal patch and the grid-shaped metal patch botTo counteract the asymmetric current, a current loop is formed, generating orthogonal magnetic fields and creating magnetic resonance. The same-direction surface currents generated on the grid-shaped metal patches in the same layer of the top and bottom layers create electrical resonance. This, combined with… Figure 4 and Figure 5 It can be determined that the electric resonance and magnetic resonance have reached a state of equilibrium, and the Huygens resonance is excited.

[0050] Figure 7 The graphs illustrating the transmission coefficient amplitude and phase of the Huygens resonator cell according to an embodiment of the present invention are shown as a function of the gap g of the angular ring metal patch. The gap width g of the angular ring metal patch varies from 0.1 to 1 mm, achieving phase coverage of 0–360° and a transmission coefficient amplitude at least higher than -2.3 dB. By adjusting this parameter, the phase and transmission coefficient of the antenna can be flexibly controlled to meet the needs of different application scenarios.

[0051] The double-layer Huygens metasurface module is composed of multiple Huygens resonant cell elements. The N-array has M and N values ​​such that the metasurface lens side length D is not less than 10 times the wavelength. Huygens resonant cell elements are arranged in the array according to the phase distribution required for the lens function. In a further embodiment, both M and N are set to 33. The double-layer Huygens metasurface module consists of 33×33 Huygens resonant cell elements, the metasurface lens side length D = 158.4 mm, the metasurface lens focal length F = 150 mm, and the ratio of the metasurface lens focal length F to the metasurface lens side length D, F / D, is 0.95.

[0052] Figures 8-10 These are, respectively, the theoretical phase distribution diagram of the ultrathin dual-polarized lens based on a double-layer Huygens metasurface according to an embodiment of the present invention, the actual phase distribution diagram of the constructed metasurface lens, and the error diagram between the actual and theoretical phases. From Figures 8-10 It can be seen that the error between the actual phase and the theoretical phase is no more than 15°, which basically meets the theoretical requirements. This verifies the accuracy and reliability of the metasurface lens module construction.

[0053] In a further embodiment, by adjusting the Huygens resonance cell sub-based Figure 9 The designed phase distribution is arranged to construct a double-layer Huygens metasurface module. Then, the phase center of the horn antenna feed module is placed at the focal point of the metalens. This converts the x-polarized or y-polarized quasi-spherical wave emitted by the horn antenna feed module into a plane wave emitted in a single direction after passing through the metalens, thereby improving the radiation gain of the horn antenna. The calculation results are as follows... Figure 11 The diagram shows the three-dimensional radiation gain of the metasurface lens antenna, with a radiation gain of up to 30.2 dBi.

[0054] Figure 12 The graphs showing the radiation gain of the ultrathin dual-polarized lens antenna based on a double-layer Huygens metasurface under x-polarized or y-polarized spherical wave excitation and the radiation gain of the horn antenna feed module as a function of frequency clearly demonstrate that the metasurface lens antenna of the present invention can significantly improve the radiation gain of the horn antenna, has a dual-polarized response, and possesses a certain bandwidth and high aperture efficiency. The highest radiation gain at the center frequency of 25 GHz is 30.2 dBi, and the -3 dB bandwidth of the lens antenna is approximately 8.6%.

[0055] Figure 13 The graphs show the aperture efficiency of the ultrathin dual-polarized lens antenna based on a double-layer Huygens metasurface under x-polarized or y-polarized spherical wave excitation, according to an embodiment of the present invention. It can be seen that the lens antenna has the same aperture efficiency under x-polarized or y-polarized spherical wave excitation, and the maximum aperture efficiency obtained at the center frequency of 25 GHz is about 47.8%.

[0056] The advantages of this invention are its dual polarization response, ultrathin thickness of less than one-tenth of the wavelength, ease of integration, high radiation gain, and high aperture efficiency, which can be widely used in millimeter-wave communication systems, wireless power transmission, and other fields.

[0057] The above embodiments are merely for illustration and to help understand the principles of the present invention and demonstrate the final effect. All those who understand or are familiar with the technology involved in this invention may modify or change the above embodiments without departing from the spirit and scope of the present invention, and should not be construed as limiting the present invention.

Claims

1. An ultra-thin dual-polarized lens antenna based on double-layered Huygens super surface, characterized in that The device includes a horn antenna feed module and a double-layer Huygens metasurface module. The double-layer Huygens metasurface module consists of an intermediate dielectric support layer and a top and bottom metal patch layer tightly bonded to the upper and lower surfaces of the intermediate dielectric support layer. The top and bottom metal patch layers have identical structures. By arranging the cell elements of the double-layer Huygens metasurface module in a hyperbolic phase distribution, a superlens function is formed. The phase center of the horn antenna feed module is located at the focal point of the superlens. When the horn antenna feed module emits a quasi-spherical wave, based on the double-layer Huygens metasurface module and the cell element arrangement, the quasi-spherical wave is efficiently converted into a plane wave emitted in a single direction, thereby improving the directivity and radiation gain of the electromagnetic wave. The top metal patch layer and the bottom metal patch layer are located on the upper and lower surfaces of the intermediate dielectric support layer, respectively. Both the top metal patch layer and the bottom metal patch layer are composed of multiple Huygens resonant cell substructures arranged in an orderly manner. Each Huygens resonant cell substructure is composed of a angular ring metal patch consisting of 4 L-shaped elements on the periphery and a grid-shaped metal patch in the center, exhibiting 90° rotational symmetry. The top and bottom structures of each Huygens resonant cell substructure are completely identical.

2. The ultra-thin dual-polarized lens antenna based on double-layered Huygens super surface according to claim 1, wherein The intermediate dielectric support layer is made of Rogers material, polyethylene, polyimide, glass or silicon dielectric material; the thickness of the intermediate dielectric support layer is less than one-tenth of the wavelength.

3. The ultra-thin dual-polarized lens antenna based on double-layered Huygens super surface according to claim 1, wherein Both the top and bottom metal patch layers are made of high-conductivity metal materials, including copper, silver, aluminum, or gold.

4. The ultra-thin dual-polarized lens antenna based on double-layered Huygens super surface according to claim 1, wherein In the top and bottom metal patch layers, the double-layer metal patches of the same Huygens resonant cell have the same structural dimensions. The cell side length p, the corner ring side length s, the double-layer spacing d, the metal patch layer thickness h, the width w of the corner ring metal patch and the grid-shaped metal patch, the grid-shaped metal patch length l, and the spacing t between the two metal strips of the grid-shaped metal patch are all fixed values ​​corresponding to the antenna operating wavelength. The gap width g of the corner ring metal patch is an adjustable parameter of the Huygens resonance. The Huygens resonance of the metal patch layer provides each cell with a transmission coefficient amplitude of more than -2.3 dB, and the adjustment of the corner ring gap width g provides 360° full phase coverage.

5. The ultrathin dual-polarized lens antenna based on a double-layer Huygens metasurface as described in claim 1, characterized in that... The double-layer Huygens super surface module is M N array, the size of M and N meets the requirement that the super surface lens side length D is not less than 10 times the wavelength, and the Huygens resonant unit cell is arranged in the array according to the required phase distribution of the lens function.

6. The ultrathin dual-polarized lens antenna based on a double-layer Huygens metasurface as described in claim 1, characterized in that... The double-layer Huygens metasurface module is composed of Huygens resonant cell sub-arrangements, according to the following hyperbolic phase distribution formula: in, For operating frequency, The speed of light in a vacuum. These are the coordinates of the cell's location. This is represented as the phase at that coordinate. = 0, 1, 2, …, M; = 0, 1, 2, …, N; p is the side length of each cell, and F represents the focal length of the metasurface lens.

7. An ultrathin dual-polarized lens antenna based on a double-layer Huygens metasurface as described in any one of claims 5 and 6, characterized in that... The ratio of the focal length F of a metasurface lens to the side length D of the metasurface lens, F / D, satisfies 0.7~1.

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