Composite metasurface array for efficiently receiving dual-polarized microwave energy and receiving method

Abstract

The invention discloses a dual-polarization microwave energy efficient receiving composite metasurface array and a receiving method, and the method comprises the steps: enabling different polarization plane waves to irradiate a polarization selective waveform conversion function region composed of biaxial symmetric split-ring resonators, and carrying out the unit differential response and reflection phase gradient arrangement, converting the x-polarized plane wave and the y-polarized plane wave into surface waves propagating in the-x direction and the y direction respectively; the square ring-shaped artificial surface plasmon polariton structure is used for receiving the surface wave, and the surface wave is stably guided to the waveform focusing and energy extraction functional area through momentum matching; by means of gradient refractive index distribution focusing surface waves of a planar semi-Maxwell fisheye lens, an equiphase surface is bent into a spherical surface shape, and energy is converged to a focus; energy is led out through the microstrip line structure at the focus, efficient transmission is achieved through impedance matching, and collection and conversion of different polarization microwave energy are completed. The polarization sensitivity problem of a traditional scheme is solved, and the microwave energy collection efficiency is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of microwave hyperthermia, and in particular to a composite metasurface array for efficiently receiving dual-polarized microwave energy and a receiving method. Background Art

[0002] With the ever-increasing demand for energy and the pursuit of clean energy, space solar power stations have become a highly sought-after area. Compared to ground-based solar power stations, space solar power stations offer significant advantages in being unaffected by atmospheric attenuation, seasonal diurnal variations, and geographic location. Consequently, they have been designated as a key development industry in many countries. As a key component of space solar power stations, the performance of long-range wireless energy receivers (Microwave Power Reception, MPR) devices, particularly the functional characteristics of the key materials and structures upon which they rely, is crucial for achieving efficient solar energy utilization.

[0003] Traditional microwave energy reception solutions initially used microstrip antenna array technology, which has obvious shortcomings in terms of polarization-insensitive reception performance. Microstrip antenna arrays generally have high reception efficiency for electromagnetic waves in a specific polarization direction, while the reception efficiency for electromagnetic waves in the orthogonal polarization direction is significantly reduced, resulting in significant polarization dependence in practical applications. The subsequent development of dual-polarization or circularly polarized antenna design solutions, although improving the polarization reception characteristics of energy, also significantly increased the complexity of the array structure. In addition, the complex combining network and a large number of rectifier circuits not only significantly increase the manufacturing cost of the system, but also the inherent combining loss and impedance mismatch problems in large-area wireless energy reception have become key factors limiting the improvement of energy reception efficiency.

[0004] In response to the limitations of traditional solutions, researchers have proposed an MPR solution based on rectifying metasurfaces, which to some extent solves the problems of polarization sensitivity and the number of converging networks. By tightly integrating the receiving unit with the rectifying circuit, the rectifying metasurface enables the incident electromagnetic wave to be efficiently converted into DC power in any polarization direction. However, this energy receiving solution still faces the following severe challenges: First, the nonlinear characteristics of the rectifying diode cause the system's conversion efficiency to vary significantly at different power densities, making it difficult to maintain high efficiency over a wide power range; second, each unit requires an independent rectifying circuit, which greatly increases the system manufacturing cost and reduces the long-term reliability of the system; in addition, the introduction of the rectifying circuit will generate additional ohmic losses and harmonic interference, affecting the overall efficiency of the system. The above problems have prompted researchers to explore new energy receiving solutions based on passive functional materials.

[0005] In recent years, with the continuous deepening of research on new functional materials, especially electromagnetic metasurfaces (EMs), researchers have discovered that leveraging their unique ability to manipulate electromagnetic waves has opened up a new, material-based design approach for achieving high-performance microwave energy harvesting. Compared with traditional solutions that rely on discrete components and complex confluence networks, EM-based MPR systems have the following significant advantages: First, EMs embody the core concept of "structure is function" and can flexibly control parameters such as the phase, amplitude, and polarization of electromagnetic waves through carefully designed subwavelength units. Second, by constructing a specific gradient phase distribution, EMs can efficiently convert plane waves propagating in free space into surface waves, theoretically approaching the energy conversion efficiency limit, thereby significantly improving energy reception efficiency. Furthermore, their inherent planar configuration and lightweight properties not only facilitate large-scale manufacturing and reduce costs, but also allow seamless integration with other systems, demonstrating the great potential and advantages of this type of functional material. Based on this advanced design concept, researchers have designed gradient refractive index metasurfaces and phase gradient metasurface arrays, but their conversion efficiency is still not very high. Although researchers have recently designed two MPR composite metasurfaces using a combination of phase gradient and refractive index gradient, achieving energy reception efficiencies exceeding 70% at 5.8 GHz, a review of the designs of these advanced passive metasurface arrays reveals that they still suffer from polarization sensitivity, meaning they are only effective for plane waves in a single polarization direction. This severely limits the potential of these functional materials in practical engineering applications, such as space solar power stations, that require coping with complex and variable polarization environments. Summary of the Invention

[0006] Based on the above technical problems, the present application discloses a composite metasurface array and a receiving method for efficiently receiving dual-polarized microwave energy, wherein the composite metasurface array for efficiently receiving dual-polarized microwave energy is specifically:

[0007] A composite metasurface array for efficient reception of dual-polarized microwave energy includes a polarization-selective waveform conversion functional area, a surface wave guiding functional area, and a waveform focusing and energy extraction functional area; the polarization-selective waveform conversion functional area includes a dual-polarization phase gradient metasurface, and the dual-polarization phase gradient metasurface is composed of a plurality of biaxially symmetric split resonant ring units, which are reasonably arranged in the x and y directions to simultaneously generate mutually independent reflection phase gradients to convert x-polarized or y-polarized plane waves into surface waves propagating in the corresponding direction; the surface wave guiding functional area is an artificial surface plasmon structure, which is closely related to the polarization. The polarization-selective waveform conversion functional area is connected to receive and guide the propagation of surface waves; the waveform focusing and energy extraction functional area includes a planar half-Maxwell fisheye lens and an energy derivation port. The planar half-Maxwell fisheye lens realizes a gradient refractive index distribution by changing the size of the square ring unit, and is connected to the surface wave guiding functional area to converge surface waves. The energy derivation port is a microstrip line structure connected to the focus of the planar half-Maxwell fisheye lens, which is used to derivate the converged surface wave energy; the polarization-selective waveform conversion functional area, the surface wave guiding functional area, and the waveform focusing and energy extraction functional area are connected in sequence to form a composite metasurface array.

[0008] Preferably, the dual-polarization phase gradient metasurface is composed of a plurality of biaxially symmetric open resonant ring units arranged periodically, and realizes differentiated response to orthogonally polarized plane waves by constructing independent reflection phase gradients in the x and y directions respectively; when the x-polarized or y-polarized plane wave is vertically incident, the dual-polarization phase gradient metasurface induces a surface current propagating in the corresponding direction through the phase gradient, efficiently converting the plane wave into a surface wave, and the reflection phase gradients in the two polarization directions both meet the condition of being greater than the vacuum wave number, so as to suppress free space radiation and enhance the surface wave coupling efficiency; the unit arrangement of the dual-polarization phase gradient metasurface forms a polarization-dependent waveform conversion code, so that plane waves of different polarizations correspond to independent surface wave propagation paths.

[0009] Preferably, the biaxially symmetrical split resonant ring unit is a sandwich structure, including a top metal pattern, an intermediate FR4 dielectric layer and a bottom metal ground plane, and its geometric configuration exhibits anisotropic electromagnetic response to electromagnetic waves incident with different polarizations; by regulating the geometric parameters of the unit, the reflection phase in the x-polarization and y-polarization directions is independently adjusted, so that the unit can achieve equally spaced phase gradient distribution in the two polarization directions; the biaxially symmetrical split resonant ring unit is arranged in a subwavelength periodic arrangement to form the basic building block of the dual-polarization phase gradient metasurface, and a continuous reflection phase gradient is formed through the phase difference between adjacent units, thereby realizing polarization-selective conversion from plane wave to surface wave.

[0010] Preferably, the surface wave guiding functional area includes an artificial surface plasmon structure and an impedance matching layer, wherein the artificial surface plasmon structure is a periodic array of square ring metal patches, and the equivalent refractive index is controlled by unit size design so that it supports a surface wave mode in which the wave vector matches the dual-polarization phase gradient metasurface, thereby realizing efficient coupling and guidance of the surface waves excited by the dual-polarization phase gradient metasurface; the impedance matching layer is arranged between the artificial surface plasmon structure and the waveform focusing functional area, and adopts the same unit type as the artificial surface plasmon structure. Through the gradient refractive index design, its equivalent refractive index is between the artificial surface plasmon structure and the waveform focusing functional area, forming a gradual transition interface to reduce the reflection loss of the surface wave at the junction of different functional areas, thereby ensuring that the surface wave energy is transmitted to the planar half-Maxwell fisheye lens with low loss along the preset path.

[0011] Preferably, the artificial surface plasmon structure is a waveguide structure formed by a periodic arrangement of square ring metal patches, printed on a thin FR4 dielectric substrate, and its unit period matches the unit period of the dual-polarization phase gradient metasurface; by designing the square ring unit size to control the propagation constant and the equivalent refractive index, the artificial surface plasmon structure supports a surface wave mode with a wave vector smaller than the phase gradient of the dual-polarization phase gradient metasurface, thereby achieving momentum matching with the dual-polarization phase gradient metasurface; the artificial surface plasmon structure is used to receive the surface wave generated by the dual-polarization phase gradient metasurface conversion, guide the surface wave to propagate stably along a preset path, and reduce the reflection loss of the surface wave at the coupling interface through the gradual transition structure, ensuring that the surface wave energy is efficiently transmitted to the waveform focusing and energy extraction functional area.

[0012] Preferably, the impedance matching layer is arranged between the artificial surface plasmon structure and the planar half Maxwell fisheye lens, and is composed of the same periodic arrangement of square ring units as the artificial surface plasmon structure; its thickness is designed to meet the impedance matching condition of one-quarter of the surface wave wavelength, and the equivalent refractive index is gradient-controlled to form a geometric mean transition distribution between the equivalent refractive index of the artificial surface plasmon structure and the equivalent refractive index at the edge of the planar half Maxwell fisheye lens; the impedance matching layer eliminates the impedance mismatch of the surface wave at the interface of different functional areas through a continuous refractive index gradient interface, suppresses reflection loss, and realizes low-loss transmission of surface wave energy from the artificial surface plasmon structure to the planar half Maxwell fisheye lens.

[0013] Preferably, the waveform focusing and energy extraction functional area includes a planar half-Maxwell fisheye lens and an energy decoupling port, wherein the planar half-Maxwell fisheye lens is a gradient refractive index structure, and the gradient change of the internal equivalent refractive index from the center to the edge is realized through the spatial gradient distribution of the square ring unit size, so that the equiphase surface of the incident surface wave gradually changes from a plane to a spherical surface, thereby converging the surface wave energy to the lens focus; the energy decoupling port is an exponential gradient microstrip line structure connected to the lens focus, and its impedance matches the equivalent impedance of the lens, which is used to convert the converged surface wave energy into a microwave signal and decoupling it to an external load. At the same time, the gradient structure design reduces the reflection loss in the energy transmission process, thereby realizing efficient collection and output of surface wave energy.

[0014] Preferably, the planar half-Maxwell fisheye lens is a gradient refractive index structure for surface wave focusing, and its refractive index distribution satisfies a specific gradient formula. By regulating the size of the square ring unit used in the guiding area, a gradient refractive index change from the center to the edge of the lens is achieved, wherein the effective refractive index at the edge of the lens is consistent with the effective refractive index of the surface wave guiding functional area, so as to receive the surface waves transmitted by the surface wave guiding functional area, and the gradient refractive index distribution is used to gradually bend the equiphase surface of the surface wave, so as to converge the energy to the lens focus, and the lens focus is connected to a microstrip line structure to extract the converged surface wave energy.

[0015] Preferably, the microstrip line structure is an exponentially gradient metal structure, which is connected to the focus of the planar half-Maxwell fisheye lens and is used to extract the concentrated surface wave energy; it achieves impedance matching with the planar half-Maxwell fisheye lens through optimized design to reduce reflection loss during surface wave transmission, so that the surface wave energy can be efficiently transmitted to the wave port output, thereby realizing the collection of incident electromagnetic wave energy.

[0016] A method for efficiently receiving dual-polarized microwave energy, comprising:

[0017] S1. Irradiating plane waves of different polarization directions onto a polarization-selective waveform conversion functional area composed of dual-axis symmetric split-ring resonant units. Utilizing the differentiated electromagnetic responses of the units to incident electromagnetic waves of different polarizations, and through a preset reflection phase gradient arrangement, the x-polarized plane wave is converted into a surface wave propagating along the -x direction, and the y-polarized plane wave is converted into a surface wave propagating along the y direction.

[0018] S2. Receive the generated surface waves through a square-ring artificial surface plasmon structure connected to the polarization-selective waveform conversion functional area, and use the momentum matching achieved by the artificial surface plasmon structure design to stably guide the surface waves to the waveform focusing and energy extraction functional area;

[0019] S3, focusing the guided surface wave through the gradient refractive index distribution of the planar half-Maxwell fisheye lens, so that the isophase surface of the surface wave gradually bends from a plane to a spherical surface, converging the energy to the lens focus;

[0020] S4. Through the microstrip line structure connected to the lens focus, the concentrated surface wave energy is extracted and efficiently transmitted through impedance matching design, completing the collection and conversion of incident microwave energy with different polarizations.

[0021] Compared with the prior art, the technical solution of this application has the following technical effects:

[0022] The present invention achieves differentiated responses to orthogonally polarized plane waves through the precise arrangement of biaxially symmetric split resonant ring units. Each biaxially symmetric split resonant ring unit adopts a sandwich structure. The combination of the top metal pattern, the middle FR4 dielectric layer and the bottom metal ground plane makes it present different reflection phases for x-polarized and y-polarized incident waves. By regulating the geometric parameters of the unit, independent reflection phase gradients are constructed in the x and y directions respectively. When the plane wave is incident vertically, the phase gradient induces surface currents along the polarization direction, efficiently converting the plane wave into a surface wave. For example, the x-polarized wave is converted into a surface wave propagating along the -x direction, and the y-polarized wave is converted into a surface wave propagating along the y direction, thereby breaking through the polarization sensitivity limitations of traditional solutions and laying the foundation for dual-polarized energy reception. This design integrates polarization-selective response and surface wave excitation into the same metasurface through the concept of "structure is function", simplifying the system complexity and improving energy conversion efficiency.

[0023] The efficient transmission of surface waves in this application relies on the synergy between the artificial surface plasmon structure and the impedance matching layer; the artificial surface plasmon structure uses a periodic array of square ring metal patches. By adjusting the unit size to control the equivalent refractive index, it supports surface wave modes with wave vectors smaller than the phase gradient of the dual-polarization phase gradient metasurface, achieving momentum matching with the dual-polarization phase gradient metasurface, and ensuring low-loss coupling of the surface wave from the dual-polarization phase gradient metasurface to the artificial surface plasmon structure. However, the refractive index difference between the artificial surface plasmon structure and the subsequent focusing functional area will lead to boundary reflection loss, so an impedance matching layer is introduced. The impedance matching layer uses the same square ring unit as the artificial surface plasmon, with a thickness designed to be one-quarter of the surface wave wavelength. The equivalent refractive index is gradient-controlled to form a geometric mean transition between the artificial surface plasmon structure and the focusing lens. This gradient interface eliminates the impedance mismatch at the interface between different functional areas, allowing the surface wave to smoothly transition to the planar half-Maxwell fisheye lens, avoiding energy loss due to reflection, thereby ensuring the phase consistency and energy integrity of the surface wave during transmission.

[0024] The waveform focusing and energy extraction functional area of ​​the present application is realized by a planar half-Maxwell fisheye lens and an exponential gradient microstrip line structure. The planar half-Maxwell fisheye lens is a gradient refractive index structure. It uses the spatial gradient distribution of the square ring unit size to gradually reduce the internal equivalent refractive index from the center to the edge, guiding the equiphase surface of the surface wave from a plane to a sphere, and focusing the energy to the lens focus. The exponential gradient microstrip line structure connected at the focus serves as an energy export port. Its impedance is precisely matched with the equivalent impedance of the lens, and the reflection loss is reduced by the gradient profile design. This design enables the concentrated surface wave energy to be efficiently converted into microwave signals and exported to the external load, while avoiding the complexity and loss problems of the traditional converging network, forming a complete link from polarization selective reception, surface wave transmission to energy focusing extraction, realizing the efficient collection and conversion of dual-polarized microwave energy, and providing a new solution based on structural engineering for the field of microwave wireless energy transmission.

[0025] The above description is only an overview of the technical solution of the present application. In order to more clearly understand the technical means of the present application so that it can be implemented in accordance with the contents of the specification, and to make the above and other purposes, features and advantages of the present application more obvious and easy to understand, the following is a detailed description of the preferred embodiment of the present application in conjunction with the accompanying drawings.

[0026] Based on the detailed description of the specific embodiments of the present application in conjunction with the accompanying drawings below, those skilled in the art will become more aware of the above and other objects, advantages and features of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the following will briefly introduce the drawings required for the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present application. For those of ordinary skill in the art, other drawings can also be obtained based on these drawings without inventive work. In all drawings, similar elements or parts are generally identified by similar reference numerals. In the drawings, the elements or parts are not necessarily drawn according to the actual scale.

[0028] Figure 1 Schematic diagram of the composite metasurface array for receiving microwave energy in dual polarization directions according to the present invention;

[0029] Figure 2 Figure 2. B-SRR structure and its reflection phase curve. (a) is a schematic diagram of the B-SRR structure. (b)-(g) are the reflection phase curves of the B-SRR under x-polarized wave excitation when the reflection phases are -170°, -110°, -50°, 10°, 70°, and 130°, and under y-polarized wave excitation.

[0030] Figure 3Basic modules for B-SRR;

[0031] Figure 4 The R-PGMs array and its PW-SW conversion, (a) is the R-PGMs array model, (b) is the E of the xoy plane when the plane wave is irradiated in the x-polarization direction and (c) in the y-polarization direction z Field strength;

[0032] Figure 5 To calculate η PS Schematic diagram of the reference plane;

[0033] Figure 6 Figure 3 is the square ring unit structure and its electromagnetic parameters. (a) is the unit model, (b) is the dispersion curve corresponding to different square ring sizes, and (c) is the fitting relationship between the refractive index n and the size a at 5.8 GHz.

[0034] Figure 7 Composite array composed of PGMs and SPP structure; (a) is the model schematic, (b) is the E of xoy plane z Field intensity distribution, (c) E in the xoz plane z Field intensity distribution;

[0035] Figure 8 is the effective refractive index distribution diagram of the planar half-Maxwell fisheye lens;

[0036] Figure 9 Surface wave integrated collection port, (a) is the structural model, (b) is the S11 curve, and (c) is the E curve of the surface wave integrated collection port in the xoy plane under the excitation of the wave port. z Field distribution;

[0037] Figure 10 is the theoretical refractive index distribution of IML and BLP;

[0038] Figure 11 To realize the composite metasurface array for receiving microwave energy in dual polarization directions, (a) is the structural model, and (b) is the xoy plane E under y polarization wave irradiation. z Field distribution; (c) xoy plane E under x-polarized wave irradiation z Field distribution;

[0039] Figure 12 (a) The current density distribution on the load resistor R of the composite array under the incident wave in the x-polarization direction and (b) the incident wave in the y-polarization direction;

[0040] Figure 13 This is the MPR composite metasurface array experiment; (a) is the test environment; (b) is the energy collection efficiency curve under the irradiation of the incident wave in the x-polarization direction; (c) is the energy collection efficiency curve under the irradiation of the incident wave in the y-polarization direction. DETAILED DESCRIPTION

[0041] In order to make the purpose, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, rather than all of the embodiments. In the following description, specific details such as specific configurations and components are provided only to help fully understand the embodiments of the present application. Therefore, it should be clear to those skilled in the art that various changes and modifications can be made to the embodiments described herein without departing from the scope and spirit of the present application. In addition, for clarity and brevity, the description of known functions and structures has been omitted in the embodiments.

[0042] It should be understood that references throughout this specification to "one embodiment" or "this embodiment" mean that a particular feature, structure, or characteristic associated with the embodiment is included in at least one embodiment of the present application. Therefore, the appearance of "one embodiment" or "this embodiment" throughout this specification does not necessarily refer to the same embodiment. Furthermore, these particular features, structures, or characteristics may be combined in any suitable manner in one or more embodiments.

[0043] In addition, the present application may repeat reference numerals and / or letters in different examples. This repetition is for the purpose of simplicity and clarity and does not in itself indicate the relationship between the various embodiments and / or settings discussed.

[0044] The term "and / or" in this article is only a description of the association relationship of associated objects, indicating that three relationships can exist. For example, A and / or B can mean: A exists alone, B exists alone, and A and B exist at the same time. The term " / and" in this article describes another type of association object relationship, indicating that two relationships can exist. For example, A / and B can mean: A exists alone, and A and B exist alone. In addition, the character " / " in this article generally indicates that the previous and subsequent associated objects are in an "or" relationship.

[0045] The term "at least one" in this article is merely a description of the association relationship between associated objects, indicating that three relationships may exist. For example, at least one of A and B can mean: A exists alone, A and B exist at the same time, and B exists alone.

[0046] It should also be noted that, in this document, relational terms such as first and second are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "include," "comprises," or any other variations thereof are intended to cover non-exclusive inclusion.

[0047] Example 1

[0048] This embodiment mainly describes a composite metasurface array for efficient reception of dual-polarized microwave energy and a polarization-selective waveform conversion functional area, specifically:

[0049] The dual-polarization microwave energy receiving composite metasurface array is composed of Figure 1 The three main components shown are: a dual-polarization phase gradient metasurface (PGM), a surface wave converging array, and an energy extraction port. The principle is as follows: when plane waves with different polarization directions impinge on the PGMs, the incoming waves with x polarization are converted into surface waves propagating in the -x direction, and the incoming waves with y polarization are converted into surface waves propagating in the y direction, because the PGM units have different response characteristics to electromagnetic waves incident with different polarization directions. These surface waves are then guided to the corresponding surface wave converging arrays, where they are efficiently converged through a half-Maxwell fisheye lens structure. Finally, a microstrip line structure connected at the lens focal point extracts the surface wave energy, achieving efficient reception of the incident electromagnetic waves.

[0050] Furthermore, the key to achieving polarization-selective response lies in the engineering design of the unit structure; Figure 2 The biaxially symmetric split ring resonator (B-SRR) structure shown in (a) exhibits distinct electromagnetic responses to incident electromagnetic waves of different polarizations. The unit cell adopts a sandwich structure, consisting of a top B-SRR metal pattern, a middle FR4 dielectric layer, and a bottom metal ground plane. The metal used is copper with a thickness of 0.035 mm. By precisely controlling the geometric parameters l1 and l2, the reflection phase of the unit cell in the x- and y-polarization directions can be independently adjusted.

[0051] After optimization, the selected unit model parameter dimensions were: h = 2 mm, p1 = 8 mm, b = 7.8 mm, and w = 0.1 mm. To efficiently determine the optimal unit dimensions, a hybrid optimization method combining a particle swarm optimization algorithm with the electromagnetic simulation software Ansys HFSS was employed during the design process. The particle swarm optimization algorithm iteratively searches for the optimal solution starting from a random solution, finding the global optimum by following the currently found optimal value.

[0052] When designing PGMs using B-SRR units, independent reflection phase gradients ξ can be generated simultaneously in the x and y directions through reasonable unit arrangement. x With ξ yWhen microwave energy is incident perpendicularly on PGMs, they exhibit unique reflection characteristics based on their reflection phase gradient. When the reflection phase gradient ξ > k0 (k0 is the vacuum wave number), the reflection phases between adjacent metasurface units differ significantly, preventing the formation of an isophase surface radiating into free space. At this point, the PGMs induce surface currents along the reflection phase gradient, enabling efficient coupling of microwave energy into surface waves.

[0053] At 5.8GHz frequency, Figure 2 Figures (b)-(g) demonstrate that by carefully selecting l1 and l2 based on the optimization results, the B-SRR unit structure can achieve six different reflection phase values: -170°, -110°, -50°, 10°, 70°, and 130° for x-polarized incident waves, with a reflection phase difference of ΔΦ = 60° between adjacent units. Furthermore, at the same frequency, a reflection phase difference of ΔΦ = 60° is also achieved for y-polarized excitation.

[0054] After parameter optimization, a B-SRR unit library was established that can achieve a reflection phase difference of ΔΦ = 60° in both the x and y directions. Based on this, the following Figure 3 The basic building block of the functional area shown in the figure contains 6×6 B-SRR units to achieve the required phase gradient independently along the x and y directions; specifically, in this functional module, the reflection phase of the units along the x direction is distributed from -170° to 130° at intervals of 60°, and the phase distribution along the y direction is also carried out at intervals of 60°. Under normal incidence conditions, this functional module can generate ξ x =ΔΦ / p1≈1.1k0>k0, which results in a reflection phase gradient that converts the plane wave into a surface wave propagating in the -x direction. Similarly, it generates ξ for the plane wave incident in the y-polarization direction. y The phase gradient of ≈1.1k0>k0 also achieves efficient conversion to surface waves propagating in the y direction; through structural design, Figure 3 The module shown implements polarization-dependent waveform conversion coding.

[0055] Furthermore, in order to construct a functional area of ​​a practical device size and keep the structural order of the super unit unchanged, a finite-size PGMs array was designed; the array consists of 4×4 super units with an array size of 196mm×196mm, as shown in Figure 2. Figure 4As shown in (a); In the electromagnetic simulation software Ansys HFSS, x-polarized plane waves and y-polarized plane waves are set to illuminate the PGMs array vertically from the z direction, and radiation boundary conditions are set in the x and y directions of the array, as well as at 0.5λ in the -z direction and 3λ in the +z direction. Through full-wave simulation calculations, when the incident wave frequency is 5.8GHz and the field strength is 1V / m under the irradiation of x-polarized and y-polarized plane waves, the Ez vector field distribution of the array in the xoy plane is as follows Figure 4 (b) and 4(c). Under the irradiation of plane waves, surface waves are excited on PGMs and propagate along the -x and y directions. According to the modified figure, it can be found that the intensity of Ez gradually increases along the propagation path, proving that the structural material can perform the functions of waveform conversion and initial guidance; the performance of this functional area is converted from plane wave to surface wave (PW-SW) by the conversion efficiency η PS To quantify, the formula is: Where, P in is the electromagnetic wave power incident on the PGMs array, P r is the reflected power, P t is the transmitted power; the specific calculation method is as follows Figure 5 As shown: In the electromagnetic simulation software Ansys HFSS, first establish a reference plane P1 on the surface of the PGMs array, and calculate the energy at P1 through the field calculator to obtain the incident power P in Then, a reference plane P2 is established at 2 wavelengths above the PGMs array, and the energy at P2 is calculated, which is the reflected power Pr. Since the array ground is a metal ground plane, the transmitted power P is verified by simulation. t Therefore, when the electric field strength of the incident plane wave is 1V / m, the PW-SW conversion efficiency of the array can be obtained by the above method: when the incident direction is x-polarization, η PSx =92.28%, when y-polarization incident, η PSy =91.43%; The above results show that the designed PGMs can effectively realize the efficient conversion of plane waves into surface waves in two polarization directions.

[0056] This implementation details the polarization-selective waveform conversion functional area in this application, which presents differentiated electromagnetic responses to electromagnetic waves incident with different polarizations through a sandwich structure design of dual-axis symmetric split resonant ring (B-SRR) units. The units are rationally arranged in the x and y directions to form independent reflection phase gradients, which can efficiently convert x-polarized and y-polarized plane waves into surface waves propagating along the -x and y directions, respectively. This breaks through the polarization sensitivity limitations of traditional schemes, realizes independent response and surface wave excitation of orthogonally polarized waves, lays the foundation for efficient reception of dual-polarized microwave energy, simplifies the system structure, and improves the targetedness and efficiency of energy conversion.

[0057] This embodiment describes the surface wave guiding functional area in detail, specifically:

[0058] like Figure 6 The artificial SPP structure (a) is a square ring metal patch structure printed on a thin FR4 dielectric substrate with a period of p² = 8 mm. The substrate and metal layer thicknesses are the same as those of the PGMs unit. Using the eigenmode solver in Ansys HFSS electromagnetic simulation software, the propagation constant β for different square ring unit sizes was calculated, and the corresponding refractive index n = β / k0 was determined.

[0059] Figure 6 (b) shows the dispersion curves corresponding to different square ring side lengths a. Figure 6 (c) shows the exponential fitting relationship curve between the ring patch size a and the refractive index n at the 5.8 GHz frequency. The fitting results show that for any refractive index n within the value range, the corresponding unit size a can be uniquely determined by the following formula: n = 0.0006657e 1.525a +61.61, and the coefficient of determination of the fitting equation reaches 0.9914, demonstrating the ability to precisely control the waveguide properties of materials through structural design.

[0060] Effective waveguiding requires momentum matching between the conversion region and the guiding region, therefore, the artificial SPP structure is designed to support a mode with a wave vector k < ξ x =ξ=1.1k0, the corresponding refractive index n SPP <ξ=1.1; This is achieved by selecting a suitable geometric parameter a; To verify the effectiveness of the SPP system, a full-wave simulation was performed, such as Figure 7 As shown in (a), when the incident wave is perpendicularly irradiated onto the PGMs array and converted into a surface wave, the surface wave is effectively coupled to the square ring SPP structure and propagates along the structure in the SPP mode. The simulation results are shown in Figure 7 As shown in Figures (b)-(c), the surface wave is successfully guided into the square ring structure and propagates stably in the SPP mode, demonstrating the effectiveness of the designed SPP structure. Furthermore, in actual simulations and experiments, since the incident wave acts only on the PGMs region, the SPP observed on the square ring structure must be generated after coupling through the PGMs. If a plane wave is directly incident on the square ring structure, the SPP mode will not be excited due to the mismatch between the incident wave and the SPP mode wave vector, further confirming the rationality of the system design.

[0061] This embodiment describes in detail how the surface wave guiding functional area in this application achieves low-loss transmission of surface waves through the synergistic effect of the artificial surface plasmon (SPP) structure and the impedance matching layer (IML). The SPP structure adopts a square ring unit array, and by adjusting the unit size to match the surface wave mode of the dual-polarization phase gradient metasurface (PGMs), it ensures efficient energy coupling. The impedance matching layer eliminates the impedance mismatch between the SPP and the focusing lens and suppresses reflection loss through the gradient refractive index design. The combination of the two enables the surface wave energy to propagate stably along the preset path, laying the foundation for subsequent focusing and energy extraction, and significantly improving the transmission efficiency and stability of the dual-polarization microwave energy receiving system.

[0062] This embodiment describes the waveform focusing and energy extraction functional areas in detail, specifically:

[0063] A planar half-Maxwell fisheye lens with a gradient refractive index structure is designed for focusing surface waves. When a surface wave propagates in a homogeneous medium at the front, its isophase surface is flat. However, when it enters the planar half-Maxwell fisheye lens, the gradient distribution of the refractive index inside the lens causes the isophase surface to gradually bend, eventually forming a spherical isophase surface at the edge of the lens, thereby focusing the energy to the focal point. The refractive index distribution of the lens satisfies the following formula: Where n1(0,0) is the equivalent refractive index at the center of the plane half-Maxwell fisheye lens, is the distance from any point on the lens to the center of the circle, and a is the radius of the lens. According to the above design, the effective refractive index of the surface wave excited by PGMs is n SPP =1.1, so the effective refractive index at the edge of the lens is set to 1.1, that is, the equivalent refractive index n1(0) at the center of the circle is determined to be 2.2. The setting radius of the lens is a = 92mm; at each position (x, y) in space, the required change in the equivalent refractive index n1(x, y) is achieved by the size of the square ring unit used in the guide area. The effective refractive index distribution of the final designed planar half-Maxwell fisheye lens is as follows Figure 8 shown.

[0064] At the focus of the lens, a surface wave integrated collection port is further designed; Figure 9 As shown in (a), a metal microstrip line with an exponential gradient is connected at the lens focus to efficiently transmit the concentrated surface wave energy to the wave port output. In order to minimize the reflection loss caused by the surface wave during the transmission between the lens and the microstrip line, the Ansys HFSS electromagnetic simulation software is used to optimize the design. Figure 9 In (a), carrier port excitation is applied at "port" and the port impedance is set to 50Ω.

[0065] By optimizing the parameters of the exponential gradient microstrip line, the impedance matching between the half-Maxwell fisheye lens and the microstrip line was finally achieved. The optimized geometric parameters are: w1 = 3.565mm, w2 = 27mm, l1 = 23mm, l2 = 36mm. 11 The simulation results are as follows Figure 9 As shown in (b), the results show that the reflection coefficient at 5.8 GHz reaches -32.1 dB, indicating that there is almost no reflection loss when the surface wave enters the microstrip line structure from the lens, achieving efficient energy collection and transmission.

[0066] like Figure 9 (c) shows the E of the xoy plane near the integrated collection port in the case of wave port feeding. z The results clearly show that the electromagnetic energy fed into the port is smoothly transmitted into the surface wave lens and ultimately forms a planar equiphase surface at the boundary layer of the planar half Maxwell fisheye lens (BLP), verifying the effectiveness and practicality of the designed integrated collection port.

[0067] In the uniform guiding area, the effective refractive index of the SPP system is 1.1, while in the focusing area, the effective refractive index at the edge of the BLP is greater than the refractive index at the boundary of the SPP system, resulting in an impedance mismatch at the interface between the electromagnetic wave and the BLP, leading to reflection loss. In order to reduce this loss, an impedance matching layer (IML) is designed between the PGMs and the BLP. According to the transmission line theory, the thickness of the IML needs to be as close to λ as possible. g / 4(λ g is the surface wave wavelength in the IML), and its refractive index should be the geometric mean of the BLP equivalent refractive index and the SPP equivalent refractive index, that is: n2(x) and n1(x,0) are the effective refractive indices of IML and BLP at the same x coordinate, respectively. The thickness of IML is set to 8 mm and it is composed of the same square ring unit as BLP. The theoretical refractive index distributions of IML and BLP are calculated as follows: Figure 10 shown.

[0068] This embodiment describes in detail how the waveform focusing and energy extraction functional area in this application achieves efficient energy convergence and extraction through a planar half-Maxwell fisheye lens and an exponentially gradient microstrip line structure. The planar half-Maxwell fisheye lens, as a gradient refractive index structure, uses the gradual change in the size of the square ring unit to control the refractive index distribution, so that the surface wave isophase surface is transformed from a plane to a sphere, focusing the energy at the focal point. The exponentially gradient microstrip line at the focal point significantly reduces reflection loss through impedance matching design, and efficiently extracts the concentrated surface wave energy to the load. This functional area realizes low-loss transmission of surface waves from focusing to collection, significantly improving the collection efficiency of dual-polarized microwave energy and the practicality of the system.

[0069] This embodiment describes in detail the simulation and experimental verification of energy collection efficiency, specifically:

[0070] The SPP system, IML and surface wave integrated collection port are integrated at the two surface wave output ends of PGMs to construct a complete MPR composite metasurface array, such as Figure 11 (a) As shown. In the electromagnetic simulation software Ansys HFSS, x- and y-polarized plane waves with electric field strengths of 1V / m were set to illuminate the PGMs array vertically from the z direction, and 50Ω load resistors R1 and R2 were loaded at "Port1" and "Port2" respectively to evaluate the overall energy harvesting performance. The electric field distribution results obtained by simulation under the two polarization directions of incidence are shown as follows Figure 11 (b) and Figure 11 (c) The simulation results show that the MPR device of this design can effectively convert the incident plane wave into a surface wave propagating along the corresponding polarization direction and introduce it into the load through the integrated collecting port. At the same time, it can be observed from the field distribution diagram that the surface wave produces almost no significant reflection when passing through the SPP system and IML, verifying the good matching performance of the designed impedance matching layer. However, as the surface wave converges toward the integrated port, some energy still escapes from the array boundary into the dielectric layer, resulting in a certain amount of energy loss.

[0071] In order to evaluate the energy collection efficiency of the composite metasurface array, it is necessary to calculate the energy loss loaded on the load resistors R1 and R2, which are recorded as Ploss1 and Ploss2 respectively. Since this composite array does not require a rectifier circuit and a complex energy convergence network, its performance is almost unaffected by changes in the incident wave power. Therefore, under ideal conditions, the energy loss Ploss can be considered to be directly equal to the energy collection power and is only related to the incident power Pin. Based on this, the energy receiving efficiency of the array is defined as follows: η col =(P loss1 +P loss2 ) / P in ; Under the condition of vertical irradiation of x-polarized wave and y-polarized wave with electric field strength of 1V / m, Figure 12The current density distribution on the load resistors R1 and R2 of the MPR composite array "Port1" and "Port2" is shown. The power dissipated on the load resistors can be calculated by the following formula: loss =I 2 R, where R is the load resistance value and I is the current on the load resistance, which can be obtained by the following formula: I = wJ surf , where J surf is the current density on the surface of the load resistor, in mA / m; w is the width of the load resistor, which is the same as the width of the 50Ω microstrip line, both are 3.47mm;

[0072] The energy collection efficiency of the composite array under different polarization directions can be calculated according to the above formula. Under the condition of plane wave irradiation in the x-polarization direction: η colx =P lossx / P in =33.25μW / 48.94μW=67.94%. Under the condition of y-polarized incident wave illumination: η coly =P lossy / P in =32.14μW / 48.94μW=65.67%. The results show that the designed dual-polarization MPR device has good energy receiving performance;

[0073] In order to further verify the actual performance of the composite array in MPR applications, an experimental prototype was prepared and tested. Figure 13 (a) shows the experimental test process under the condition of plane wave irradiation in the y-polarization direction. The 5.8GHz different power signals generated by the signal source are first amplified by the power amplifier and then input to the power meter to achieve input power P A After calibration, connect the output of the power amplifier to a standard gain horn antenna operating at 5.8 GHz. The output power of the horn antenna is the calibrated P A To simulate the plane wave illumination scenario, the composite array to be tested is placed in the far field area about 1.2m away from the horn antenna, and the center of the antenna is ensured to be on the same horizontal line as the center of the array. A rectangular waveguide is used to measure the electromagnetic power density in different areas of the array, and the incident power P is calculated based on the array surface area. in Solder 50Ω standard RF connectors to the two energy collection ports of the composite array and connect them to a power meter to test the energy collection efficiency η. out By rotating the horn antenna direction, the MPR device is simulated with different polarized waves.

[0074] The test results are as follows Figure 13 (b) and Figure 13As shown in (c), it can be found that as the input power Pin changes, the energy collection efficiency of the composite array remains basically unchanged, indicating that the energy receiving efficiency is not affected by the incident wave power. In the experimental test, the measurement was carried out in a step size of 0.1GHz in the 5-6GHz frequency band. The results show that the MPR device has good energy collection performance in the range of 5.8-6.0GHz. Among them, under the irradiation of the incident wave in the x-polarization direction, the energy receiving efficiency can reach up to 61.43% (P in =1W). Compare Figure 13 (b) and Figure 13 (c) It can be seen that the receiving efficiency under the y-polarized wave is slightly lower. This is mainly because during the test in the y-polarized direction, Port2 is interfered by the external environment such as the tripod, resulting in additional energy loss, such as Figure 13 (a). In addition, due to factors such as manufacturing tolerance and experimental error, the energy receiving efficiency in the actual test is slightly lower than the simulation result, and as Pin changes, η out Despite this, the MPR device proposed in this study can still achieve a measured energy reception efficiency of over 50% in the 5.8–6.0 GHz frequency band, fully demonstrating its good adaptability and stability to incident waves of different polarizations.

[0075] The detailed description of this embodiment verifies that it can achieve an energy receiving efficiency of more than 50% in the 5.6-6.0GHz frequency band, with the highest value of 61.43% reached at 5.8GHz, demonstrating excellent broadband characteristics and robustness. The solution of this application has a simple structure, high energy conversion efficiency, and low manufacturing cost. It has significant advantages over traditional polarization-insensitive PGMs devices and provides a new technical path and theoretical reference for future related research.

[0076] The above are only preferred embodiments of the present invention, which do not limit the scope of protection of the present invention. For those skilled in the art, the present invention can be modified and varied in various ways. Any changes, modifications, replacements, integrations and parameter changes to these embodiments through conventional substitutions or that can achieve the same functions without departing from the principles and spirit of the present invention fall within the scope of protection of the present invention.

Claims

1. A composite metasurface array for efficient reception of dual-polarized microwave energy, characterized in that: It includes a polarization-selective waveform conversion functional area, a surface wave guiding functional area, and a waveform focusing and energy extraction functional area; the polarization-selective waveform conversion functional area includes a dual-polarization phase gradient metasurface, which is composed of a plurality of biaxially symmetrical split resonant ring units. The plurality of biaxially symmetrical split resonant ring units are reasonably arranged in the x and y directions to simultaneously generate independent reflection phase gradients to convert x-polarized or y-polarized plane waves into surface waves propagating in the corresponding direction; the surface wave guiding functional area is an artificial surface plasmon structure, which is consistent with the polarization-selective waveform conversion functional area. The waveform focusing and energy extraction functional area is connected to the surface wave guiding functional area for receiving and guiding the propagation of surface waves; the waveform focusing and energy extraction functional area includes a planar half-Maxwell fisheye lens and an energy derivation port. The planar half-Maxwell fisheye lens realizes a gradient refractive index distribution by changing the size of the square ring unit, and is connected to the surface wave guiding functional area to converge the surface waves. The energy derivation port is a microstrip line structure connected to the focus of the planar half-Maxwell fisheye lens, which is used to derivate the converged surface wave energy; the polarization selective waveform conversion functional area, the surface wave guiding functional area, and the waveform focusing and energy extraction functional area are connected in sequence to form a composite metasurface array.

2. The composite metasurface array for efficient dual-polarized microwave energy reception according to claim 1, characterized in that: The dual-polarization phase gradient metasurface is composed of a plurality of biaxially symmetric open resonant ring units arranged periodically. By constructing independent reflection phase gradients in the x and y directions respectively, it achieves differentiated responses to orthogonally polarized plane waves. When an x-polarized or y-polarized plane wave is vertically incident, the dual-polarization phase gradient metasurface induces a surface current propagating in the corresponding direction through the phase gradient, efficiently converting the plane wave into a surface wave. Moreover, the reflection phase gradients in the two polarization directions both meet the condition of being greater than the vacuum wave number, thereby suppressing free-space radiation and enhancing the surface wave coupling efficiency. The unit arrangement of the dual-polarization phase gradient metasurface forms a polarization-dependent waveform conversion code, so that plane waves of different polarizations correspond to independent surface wave propagation paths.

3. The composite metasurface array for efficient dual-polarized microwave energy reception according to claim 2, characterized in that: The biaxially symmetric split resonant ring unit is a sandwich structure, including a top metal pattern, an intermediate FR4 dielectric layer, and a bottom metal ground plane. Its geometric configuration exhibits anisotropic electromagnetic response to electromagnetic waves incident with different polarizations. By regulating the geometric parameters of the unit, the reflection phase in the x-polarization and y-polarization directions is independently adjusted, so that the unit can achieve equally spaced phase gradient distribution in the two polarization directions. The biaxially symmetric split resonant ring units are arranged in a subwavelength periodic arrangement to form the basic building block of the dual-polarization phase gradient metasurface. A continuous reflection phase gradient is formed through the phase difference between adjacent units, thereby realizing polarization-selective conversion from plane waves to surface waves.

4. The composite metasurface array for efficient dual-polarized microwave energy reception according to claim 1, characterized in that: The surface wave guiding functional area includes an artificial surface plasmon structure and an impedance matching layer, wherein the artificial surface plasmon structure is a periodic array of square ring metal patches. The equivalent refractive index is controlled by unit size design to support a surface wave mode in which the wave vector matches the dual-polarization phase gradient metasurface, thereby achieving efficient coupling and guidance of surface waves excited by the dual-polarization phase gradient metasurface; the impedance matching layer is arranged between the artificial surface plasmon structure and the waveform focusing functional area, using the same unit type as the artificial surface plasmon structure. The equivalent refractive index is designed to be between the artificial surface plasmon structure and the waveform focusing functional area through a gradient refractive index design, forming a gradual transition interface to reduce the reflection loss of the surface wave at the junction of different functional areas, ensuring that the surface wave energy is transmitted to the planar half-Maxwell fisheye lens with low loss along a preset path.

5. The composite metasurface array for efficient dual-polarized microwave energy reception according to claim 1, characterized in that: The artificial surface plasmon structure is a waveguide structure formed by a periodic arrangement of square ring metal patches, printed on a thin FR4 dielectric substrate, and its unit period matches the unit period of the dual-polarization phase gradient metasurface. By designing the square ring unit size to control the propagation constant and equivalent refractive index, the artificial surface plasmon structure supports surface wave modes with wave vectors smaller than the phase gradient of the dual-polarization phase gradient metasurface, achieving momentum matching with the dual-polarization phase gradient metasurface. The artificial surface plasmon structure is used to receive surface waves generated by the dual-polarization phase gradient metasurface conversion, guide the surface waves to propagate stably along a preset path, and reduce the reflection loss of the surface waves at the coupling interface through a gradual transition structure, ensuring that the surface wave energy is efficiently transmitted to the waveform focusing and energy extraction functional areas.

6. The composite metasurface array for efficient dual-polarized microwave energy reception according to claim 1, characterized in that: The impedance matching layer is arranged between the artificial surface plasmon structure and the planar half-Maxwell fisheye lens, and is composed of a periodic arrangement of square ring units identical to those of the artificial surface plasmon structure. Its thickness is designed to meet an impedance matching condition of one-quarter of the surface wave wavelength, and its equivalent refractive index is gradient-controlled to form a geometric mean transition distribution between the equivalent refractive index of the artificial surface plasmon structure and the equivalent refractive index at the edge of the planar half-Maxwell fisheye lens. The impedance matching layer eliminates impedance mismatch at the interface of different functional zones of the surface wave through a continuous refractive index gradient interface, suppresses reflection loss, and achieves low-loss transmission of surface wave energy from the artificial surface plasmon structure to the planar half-Maxwell fisheye lens.

7. The composite metasurface array for efficient dual-polarized microwave energy reception according to claim 1, characterized in that: The waveform focusing and energy extraction functional area includes a planar half-Maxwell fisheye lens and an energy output port, wherein the planar half-Maxwell fisheye lens is a gradient refractive index structure, which realizes a gradient change of the internal equivalent refractive index from the center to the edge through the spatial gradient distribution of the square ring unit size, so that the equiphase surface of the incident surface wave gradually changes from a plane to a spherical surface, thereby converging the surface wave energy to the lens focus; The energy export port is an exponentially tapered microstrip line structure connected to the focus of the lens. Its impedance matches the equivalent impedance of the lens. It is used to convert the concentrated surface wave energy into a microwave signal and export it to an external load. At the same time, the gradient structure design reduces the reflection loss during energy transmission, thereby achieving efficient collection and output of surface wave energy.

8. The composite metasurface array for efficient dual-polarized microwave energy reception according to claim 7, characterized in that: The planar half-Maxwell fisheye lens is a gradient refractive index structure used for surface wave focusing. Its refractive index distribution satisfies a specific gradient formula. By regulating the size of the square ring units used in the guiding area, a gradient refractive index change from the center to the edge of the lens is achieved. The effective refractive index at the edge of the lens is consistent with the effective refractive index of the surface wave guiding functional area, so as to receive the surface waves transmitted by the surface wave guiding functional area. The gradient refractive index distribution gradually bends the isophase plane of the surface wave, converging the energy to the lens focus. The lens focus is connected to a microstrip line structure to extract the concentrated surface wave energy.

9. The composite metasurface array for efficient dual-polarized microwave energy reception according to claim 7, characterized in that: The microstrip line structure is an exponentially gradient metal structure, connected to the focus of the planar half-Maxwell fisheye lens, and is used to guide the concentrated surface wave energy out; It achieves impedance matching with the planar half-Maxwell fisheye lens through optimized design to reduce reflection loss during surface wave transmission, so that the surface wave energy can be efficiently transmitted to the wave port output, thereby realizing the collection of incident electromagnetic wave energy.

10. A method for efficiently receiving dual-polarized microwave energy, applicable to any one of claims 1 to 9, characterized in that: include: S1. Irradiating plane waves of different polarization directions onto a polarization-selective waveform conversion functional area composed of dual-axis symmetric split-ring resonant units. Utilizing the differentiated electromagnetic responses of the units to incident electromagnetic waves of different polarizations, and through a preset reflection phase gradient arrangement, the x-polarized plane wave is converted into a surface wave propagating along the -x direction, and the y-polarized plane wave is converted into a surface wave propagating along the y direction. S2. Receive the generated surface waves through a square-ring artificial surface plasmon structure connected to the polarization-selective waveform conversion functional area, and use the momentum matching achieved by the artificial surface plasmon structure design to stably guide the surface waves to the waveform focusing and energy extraction functional area; S3, focusing the guided surface wave through the gradient refractive index distribution of the planar half-Maxwell fisheye lens, so that the isophase surface of the surface wave gradually bends from a plane to a spherical surface, converging the energy to the lens focus; S4. Through the microstrip line structure connected to the lens focus, the concentrated surface wave energy is extracted and efficiently transmitted through impedance matching design, completing the collection and conversion of incident microwave energy with different polarizations.

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