Conformal non-reciprocal amplitude and phase independent adjustable digital coding metasurface

Abstract

The invention discloses a conformal non-reciprocal amplitude and phase independent adjustable digital coding metasurface, the coding metasurface is composed of a plurality of units, accurate regulation and control of the phase and the amplitude of transmission electromagnetic waves can be realized simultaneously by adjusting the opening and the orientation of a C-shaped circular ring of a middle layer of each unit, and the phase and the amplitude are mutually independent. The unit material can be bent to realize conformality, and the super surface is a conformal coding super surface. Two metasurface units are arranged in a staggered mode, amplitude phases of the two metasurface units are coded respectively, then the metasurface is integrally bent, the metasurface achieves different function regulation and control on electromagnetic waves incident in the forward direction and the reverse direction, and the non-reciprocal conformal metasurface is achieved. The conformal and nonreciprocal amplitude and phase independent adjustable digital coding metasurface provided by the invention is conformal and nonreciprocal, can effectively improve the information capacity and degree of freedom of the metasurface, realizes multifunctional multiplexing, and has important application prospects in the fields of wireless communication, radar, imaging, signal processing and the like.

Description

Technical Field

[0001] This invention is a conformal, non-reciprocal, amplitude- and phase-independently tunable digitally coded metasurface, belonging to the fields of antenna technology and novel artificial electromagnetic metamaterials. Background Technology

[0002] Metamaterials, sometimes also called novel artificial electromagnetic materials, novel artificial electromagnetic media, or special media, derive their English name from the Latin word "meta-," meaning "beyond." Metamaterials are artificial composite structures or composite materials created by arranging macroscopic basic units with specific geometric shapes periodically or aperiodically, giving them extraordinary electromagnetic properties not found in natural materials. Within the research branch of metamaterials, coded metasurfaces, with their excellent programmable electromagnetic control characteristics, have demonstrated outstanding technological advantages in the field of intelligent beamforming and have attracted widespread attention from the communications industry. In recent years, as one of the key development directions in metamaterials research, coded metasurfaces have shown significant application potential in realizing dynamically reconfigurable electromagnetic functions.

[0003] The conformal non-reciprocal amplitude-phase-independent tunable digitally coded metasurface proposed in this invention is a two-dimensional metamaterial, typically composed of an array of periodically or aperiodically arranged two-dimensional subwavelength structural units. Compared to ordinary coded metasurfaces, the unique advantage of the conformal non-reciprocal amplitude-phase-independent tunable digitally coded metasurface lies in its ability to simultaneously and independently control the amplitude and phase spatial distribution of the subwavelength structural units on the metasurface during electromagnetic wave transmission, thereby achieving flexible and precise control over the wavefront, polarization, and propagation direction of the transmitted wave. Furthermore, this metasurface possesses excellent bending properties, enabling its use in fabricating conformal metasurfaces; it can also exhibit different transmission effects for linearly polarized electromagnetic waves incident in the forward and reverse directions, thus achieving spatial angle multiplexing functionality and demonstrating non-reciprocal characteristics. Summary of the Invention

[0004] The purpose of this invention is to propose a conformal, non-reciprocal, amplitude-phase independently adjustable digitally coded metasurface. The materials constituting this metasurface, such as ITO, PET, and PMMA, have good bending characteristics. By adjusting the opening size and opening direction of the C-type ITO ring in the middle layer of the metasurface unit, the phase and amplitude of the incident linearly polarized electromagnetic wave can be independently controlled simultaneously. Furthermore, by arranging two types of metasurface units alternately on this metasurface, the different functions of the forward and reverse incident linearly polarized electromagnetic waves can be controlled, thereby realizing a non-reciprocal conformal metasurface.

[0005] To achieve the above objectives, the present invention provides a conformal non-reciprocal amplitude and phase independently adjustable digital coded metasurface using the following technical solution: the digital coded metasurface is composed of 60 × 60 basic units arranged periodically, each basic unit consisting of a first ITO-PET film layer (1), a first PMMA dielectric layer (2), a second ITO-PET film layer (3), a second PMMA dielectric layer (4), and a third ITO-PET film layer (5) stacked sequentially; the first ITO-PET film layer (1) is a rectangular strip of ITO processed on a PET substrate by laser processing, the second ITO-PET film layer (3) is a C-shaped pattern of ITO processed on a PET substrate by laser processing, and the third ITO-PET film layer (5) is a rectangular strip of ITO processed on a PET substrate by laser processing.

[0006] The basic unit structure has a period of 4.5 mm.

[0007] The first ITO-PET film layer (1) has three rectangular ITO strips with a length of 4.5 mm, a width of 0.5 mm, and a spacing of 0.7 mm between the three rectangular strips.

[0008] The inner radius of the C-shaped ITO ring on the second ITO-PET film layer (3) is 1.5 mm, the outer radius is 2 mm, and the opening angle is between -45 degrees and +45 degrees.

[0009] The three rectangular ITO strips on the third ITO-PET film layer (5) are 4.5 mm long and 0.5 mm wide, and the interval between the three rectangular strips is 0.7 mm.

[0010] The first ITO-PET film layer (1) with rectangular ITO strips rotated 90 degrees clockwise coincides with the third ITO-PET film layer (5) with rectangular ITO strips.

[0011] The PET substrate in the ITO-PET film layer has a length of 4.5 mm, a width of 4.5 mm, and a thickness of 0.175 mm.

[0012] The thickness of the first PMMA dielectric layer (2) is 2 mm, the thickness of the second PMMA dielectric layer (4) is 2 mm, the dielectric constant of the two dielectric layers is 2.9, and the tangent loss angle is 0.001.

[0013] The metasurface unit structure consists of an ITO-PET thin film layer and a dielectric layer. The conformal metasurface, which is composed of 60×60 of these units arranged in a periodic manner, has a light transmittance of 38.5% and good optical transmittance.

[0014] The metasurface is composed of a combination of two encoding schemes. The first encoding scheme is used to control linearly polarized electromagnetic waves incident in the forward direction, and the second encoding scheme is used to control linearly polarized electromagnetic waves incident in the reverse direction. The two encoding schemes are arranged in an overlapping manner.

[0015] In the first encoding scheme, the opening direction and size of the C-shaped ITO ring of the second ITO-PET thin film layer (3) are changed, and the mapping with amplitude and phase is realized, so that the forward-incident linearly polarized electromagnetic wave is effectively modulated; in the second encoding scheme, the opening direction and size of the C-shaped ITO ring of the second ITO-PET thin film layer (3) are changed, and the mapping with amplitude and phase is realized, so that the reverse-incident linearly polarized electromagnetic wave is effectively modulated.

[0016] In the first encoding scheme, the long side of the rectangular ITO strip on the first ITO-PET film layer (1) is parallel to the X-axis, and the polarization direction of the electromagnetic wave incident in the forward direction is along the Y-axis; in the second encoding scheme, the long side of the rectangular ITO strip on the first ITO-PET film layer is parallel to the Y-axis, the polarization direction of the electromagnetic wave incident in the forward direction is along the X-axis, and the working frequency of the electromagnetic wave is 19GHz.

[0017] The conformal metasurface fabricated based on this metasurface unit consists of 60×60 basic unit structures arranged periodically, arranged along the X-axis and bent 180 degrees towards the -Z-axis, with a bending radius R of 84.2 mm. The pattern coverage area of ​​the first ITO-PET thin film layer (1) of this conformal metasurface is 270×270 mm. 2 Furthermore, the conformal metasurface's unit structure is divided into two groups, A and B, arranged in a checkerboard pattern. By designing these two groups and converting the designed amplitude and phase distributions into the unit's geometric parameters, multi-focusing can be achieved in the near-field reverse space when a Y-polarized electromagnetic wave is incident on the conformal metasurface along the +Z axis. The number and intensity of these focal points can be independently controlled. Conversely, when a Y-polarized electromagnetic wave is incident on the conformal metasurface along the -Z axis, multi-beam generation is achieved in the far-field forward space, with the direction and intensity of the beams also independently controllable.

[0018] Beneficial Effects: This invention proposes a conformal, non-reciprocal amplitude-phase independently tunable digitally coded metasurface, which possesses the ability to simultaneously and independently adjust both amplitude and phase. It also exhibits both conformal and non-reciprocal characteristics. When the operating frequency of the incident linearly polarized electromagnetic wave is 19 GHz, by adjusting the amplitude and phase response of the A and B group unit structures on the conformal metasurface, the propagation direction of the incident electromagnetic wave can be multiplexed, allowing the same incident electromagnetic wave to exhibit different transmission effects when incident from the forward / reverse direction. This invention's conformal, non-reciprocal amplitude-phase independently tunable digitally coded metasurface achieves, for the first time, precise and independent control of the amplitude and phase of electromagnetic waves on a conformal substrate. Simultaneously, by utilizing the staggered arrangement of non-reciprocal units, different functional responses of electromagnetic waves incident from the forward / reverse direction are successfully realized, and the metasurface can maintain excellent electromagnetic performance even under bending conditions. The multifunctional integration characteristics of this invention significantly enhance the application potential of metasurfaces in 5G / 6G communication, smart sensing, conformal antennas, and other fields, opening up new avenues for the development of next-generation wearable electromagnetic devices. Attached Figure Description

[0019] Figure 1 is a perspective view of the basic unit.

[0020] Figure 2 shows the structural dimensions of the basic unit. By changing the opening direction α and opening size β of the C-shaped ITO ring in the unit structure, the amplitude and phase response of the unit can be independently controlled.

[0021] Figure 3a The simulated phase response diagrams of the designed unit at a working frequency of 19 GHz, with different β values ​​as a function of α, are shown. Figure 3b This is a simulation of the amplitude response.

[0022] Figure 4 shows the ratio of the transmission coefficients of the basic unit under forward / reverse incident wave illumination.

[0023] Figure 5 shows the light transmittance test results for different materials.

[0024] Figure 6 shows the light transmittance test results of a conformal metasurface.

[0025] Figure 7 is a schematic diagram of the transmission results of the conformal metasurface under forward / reverse incident wave irradiation, with the incident wave operating frequency being 19 GHz.

[0026] Figure 8 shows the simulation results of the conformable metasurface under forward / reverse Y-polarized wave irradiation, with the incident wave operating frequency being 19 GHz. Detailed Implementation

[0027] The conformal non-reciprocal amplitude and phase independently adjustable digital coded metasurface of the present invention is composed of 60 × 60 basic units arranged periodically. Each basic unit is composed of a first ITO-PET film layer (1), a first PMMA dielectric layer (2), a second ITO-PET film layer (3), a second PMMA dielectric layer (4), and a third ITO-PET film layer (5) stacked in sequence. The first ITO-PET film layer (1) is a rectangular strip of ITO processed on a PET substrate by laser processing. The second ITO-PET film layer (3) is a C-shaped pattern of ITO processed on a PET substrate by laser processing. The third ITO-PET film layer (5) is a rectangular strip of ITO processed on a PET substrate by laser processing.

[0028] The basic unit structure has a period of 4.5 mm.

[0029] The thickness of the first PMMA dielectric layer (2) is 2 mm, the thickness of the second PMMA dielectric layer (4) is 2 mm, the dielectric constant of the two dielectric layers is 2.9, and the tangent loss angle is 0.001.

[0030] The three rectangular ITO strips on the first ITO-PET film layer (1) are 4.5 mm long and 0.5 mm wide, with a spacing of 0.7 mm between them. The geometric dimensions of the rectangular ITO strips on the third ITO-PET film layer (5) are the same as those on the first ITO-PET film layer (1). The rectangular ITO strips of the first ITO-PET film layer are rotated 90 degrees clockwise and then coincide with the rectangular ITO strips of the third ITO-PET film layer.

[0031] The metasurface unit structure uses polyethylene terephthalate (PET) as the substrate for the ITO layer pattern and polymethyl methacrylate (PMMA) as the dielectric layer in the middle of the ITO-PET film layer. The metasurface composed of this unit structure can be bent with a bending angle between 0 and 180 degrees.

[0032] The metasurface is composed of two encoding schemes. The first encoding scheme is used to control linearly polarized electromagnetic waves incident in the forward direction, and the second encoding scheme is used to control linearly polarized electromagnetic waves incident in the reverse direction. The two encoding schemes are arranged in an overlapping manner.

[0033] The following detailed description, with reference to the accompanying drawings, describes a conformal, non-reciprocal, amplitude- and phase-independently tunable digitally coded metasurface proposed in this invention: First, a unit cell with fully spaced amplitude- and phase-independently tunable parameters is designed. This unit cell is simulated using CST MWS electromagnetic simulation software. At an operating frequency of 19 GHz, the simulation yields the relationship between the phase response and amplitude response of the metasurface unit cell as a function of α and β.

[0034] like Figures 3a-3b As shown, at an electromagnetic wave operating frequency of 19 GHz, the phase response and amplitude response of this metasurface unit vary with the value of β at different α values. The simulation results in the figure show that by setting appropriate α and β values, the phase of this metasurface unit can cover a range from 0 to 2. The amplitude can vary between 0 and 0.77, and by setting the values ​​of α and β, the metasurface unit can be made into a 3-bit discrete phase code.

[0035] Secondly, for this metasurface unit, when an X-polarized incident wave is incident along the -Z axis, its output is a Y-polarized outgoing wave. The complex amplitude of this outgoing wave is set as the positive transmission coefficient. When an X-polarized incident wave is incident along the +Z axis, its output is a Y-polarized outgoing wave. The complex amplitude of this outgoing wave is set to the reverse transmission coefficient. For this metasurface unit, its forward and reverse transmission coefficients are compared under different encoding states, such as... Figure 4 As shown, the ratio of its forward transmission coefficient to its reverse transmission coefficient is greater than 160 under different encoding conditions, which proves that the metasurface unit has good asymmetric transmission characteristics.

[0036] Next, as Figure 5 As shown, in a planar state, the average light transmittance of a single ITO-PET film layer in this metasurface unit is approximately 75.2%, the average light transmittance of two ITO-PET film layers is approximately 56.5%, the average light transmittance of three ITO-PET film layers is approximately 46.2%, and the average light transmittance of the metasurface unit obtained by combining ITO-PET film layers and PMMA dielectric layers is approximately 39.1%. Subsequently, the average light transmittance of the prepared conformal metasurface sample was tested. This conformal metasurface is composed of 60×60 basic units and is bent at 180°, as shown... Figure 6 As shown, the average light transmittance of the conformal metasurface was 38.5% as measured by the LS116 transmittance meter, which proves that the conformal metasurface still has good optical transmittance even in the conformal bending state.

[0037] The conformal non-reciprocal amplitude and phase independently adjustable digital coded metasurface proposed in this invention is composed of an ITO-PET thin film layer and a PMMA dielectric layer. The metasurface composed of this metasurface unit can maintain excellent performance under bending conditions. Based on its material properties, a conformal metasurface was constructed to verify the metasurface's control over multi-beam deflection and multi-focusing under bending conditions.

[0038] When the state of a metasurface changes from planar to conformal, accurately determining the amplitude and phase distribution of its surface is crucial. For conformal metasurfaces, in order to enable the manipulation of electromagnetic waves, it is first necessary to analyze the geometry of the metasurface, and then calculate the propagation phase distribution of the electromagnetic waves arriving at the metasurface. The propagation phase distribution at different locations on the metasurface is determined by calculating the path length and path difference of the electromagnetic wave at each point. Then, the required phase distribution is calculated. Finally, its actual phase distribution is obtained, and the actual phase is equal to .

[0039] The following constructs a cylindrical conformal metasurface consisting of 60×60 basic elements, bent 180° from the X-axis to the +Z-axis with a bending radius of R = 84.2 mm. Since this conformal metasurface is no longer a simple planar structure, its far-field calculation parameters need to be adjusted. This conformal structure introduces variables on the Z-axis, so the element position vector in the m-th row and n-th column on the modified metasurface... and the unit vector in the direction of the metasurface beam target It can be written in the following form:

[0040] (1) (2)

[0041] In equation (1), Represents the spatial position on the metasurface The unit position vector at that location, , , These represent the element position vectors along the x-axis, y-axis, and z-axis in a three-dimensional Cartesian coordinate system, respectively. , , These represent the coordinate components of the m-th row and n-th column element on the hypersurface in the x-axis, y-axis, and z-axis of the three-dimensional Cartesian coordinate system.

[0042] In equation (2), Represents the unit vector along the target direction of the metasurface beam. , , These represent the element position vectors along the x-axis, y-axis, and z-axis in a three-dimensional Cartesian coordinate system, respectively. , These represent the angle between the target direction and the z-axis, and the angle between the projection of the target direction onto the xy-plane and the x-axis, respectively.

[0043] Because coordinates along the Z-axis are introduced, the far-field radiation pattern of a conformal metasurface can be expressed by the following formula:

[0044] (3)

[0045] In equation (3), The image shows the far-field scattering pattern of the metasurface, where M and N represent the number of elements in the row and column directions of the metasurface, respectively. Represents the spatial position on the metasurface Amplitude distribution at that location, Represents the spatial position on the metasurface Phase distribution at that location, The wave number represents electromagnetic waves. , , These represent the coordinate components of the m-th row and n-th column element on the hypersurface along the x, y, and z axes in a three-dimensional Cartesian coordinate system. , These represent the angle between the target direction and the z-axis, and the angle between the projection of the target direction onto the xy-plane and the x-axis, respectively.

[0046] By combining this with the principle of complex amplitude superposition, multiple beams can be generated simultaneously, and the energy of each beam can be controlled independently. For conformal metasurfaces, the amplitude and phase required to generate and control multiple beams can be obtained by the following formulas:

[0047]

[0048] (4)

[0049] In equation (4), To generate multi-beam metasurface spatial position Complex amplitude distribution at point A n (m,n) represents the spatial position when the nth beam is generated on the metasurface. The amplitude response at that point, This represents the geometric phase compensation response of the metasurface to an incident linearly polarized electromagnetic wave. The spatial position when the nth beam is generated on the metasurface The phase modulation amount at that point.

[0050] For this conformal metasurface, dual-beam output is achieved by setting the amplitude and phase distribution of the metasurface unit structure. The two beams are symmetrically distributed along the +Z axis and emitted at angles of θ = ±20°. Due to the superposition of different complex amplitudes set before the design, there is a 5.5dB intensity difference between beam 1 and beam 2. Experiments have verified that the conformal metasurface can achieve beam scanning within the range of θ = ±10° to θ = ±40°. Moreover, the conformal metasurface can not only output dual beams but also be extended to achieve multi-beam output, while precisely controlling the intensity and direction of the multi-beams.

[0051] Next, a cylindrical conformal metasurface composed of 60×60 basic units was constructed, which was bent 180° from the X-axis to the -Z-axis with a bending radius of R = 84.2 mm. Complex addition was applied to this conformal metasurface using the following complex amplitude formula. This allows it to generate multiple focal points.

[0052]

[0053] (5)

[0054] In equation (5), focal plane Complex amplitude distribution at the location, This represents generating N focal points. This represents the complex amplitude corresponding to the nth focus on the metasurface. The spatial position when the nth focus is generated on the metasurface. The corresponding phase modulation amount, , , These represent the spatial coordinates of the nth focus in a three-dimensional Cartesian coordinate system. The spatial position when the nth focus is generated on the metasurface. Phase response at that point, , , These represent the spatial coordinate variables along the x-axis, y-axis, and Z-axis in a three-dimensional Cartesian coordinate system, respectively. , , , where is the focal length of the nth focus on the focal plane and the coordinates of the focus on the focal plane.

[0055] By arranging the unit structures on a conformal metasurface according to a specific coding sequence, two focal points can be presented on an 85mm focal plane. Due to the superposition of different complex amplitudes, the energy intensities of the two focal points differ, thus confirming that the conformal metasurface design facilitates precise multi-parameter control of far-field beams and can manipulate the near-field electromagnetic energy distribution. Subsequent experiments verified that this conformal metasurface can not only control two focal points but also perform fine and independent control of multiple focal points.

[0056] like Figure 7 As shown, based on the experimentally verified conclusions of this metasurface unit, an optically transparent conformal double-sided metasurface was designed. By setting appropriate unit encoding for this conformal double-sided metasurface, different transmission effects can be achieved for Y-polarized electromagnetic waves incident from different directions. This optically transparent conformal double-sided metasurface consists of 60×60 unit structures, arranged along the X-axis and bent 180° towards the -Z-axis. Its surface unit structures are divided into groups A and B. According to the previously given formula, by reasonably setting the amplitude and phase response of group A and group B unit structures, angle reuse can be achieved on this metasurface. Figure 8 As shown, for this metasurface, when a Y-polarized electromagnetic wave is incident along the +Z axis, two focal points with different energy intensities are generated in the near field of the opposite direction. Conversely, when a Y-polarized electromagnetic wave is incident along the -Z axis, two beams with different energy distributions are formed in the far field of the forward direction. Subsequent experiments have verified that this optically transparent conformal double-sided metasurface can also achieve multi-focal focusing in the near field and multi-beam generation in the far field on both sides, and the number and intensity of the focal points can be independently controlled, as can the direction and intensity of the beams.

[0057] In summary, compared with existing technologies, the conformal non-reciprocal amplitude and phase independently tunable digitally coded metasurface proposed in this invention improves the bending performance of the unit structure by utilizing a design combination of three ITO-PET thin film layers and two PMMA dielectric layers, while exhibiting good light transmittance. By changing the opening angle and opening direction of the C-shaped ITO ring in the second ITO-PET thin film layer (3) of the unit structure, the phase and amplitude of the incident linearly polarized electromagnetic wave can be controlled. Furthermore, the amplitude control range of the incident linearly polarized electromagnetic wave is 0 to 0.77, and the phase control range is 0 to 2. Furthermore, the metasurface constructed from this basic unit exhibits excellent bending performance. By arranging the unit structures on the metasurface into checkerboard-like A and B group unit structures, and then rationally setting the amplitude and phase response of the A and B group unit structures, the conformal metasurface can achieve angle reuse. That is, linearly polarized electromagnetic waves incident from the forward and reverse directions will have different exit effects when passing through the metasurface, thus demonstrating the metasurface's multi-beam generation and multi-focus focusing control capabilities. This confirms that the conformal non-reciprocal amplitude and phase independently adjustable digitally coded metasurface proposed in this invention integrates multiple functions. Moreover, it significantly enhances the application potential of metasurfaces in 5G / 6G communication, intelligent sensing, conformal antennas, and other fields, opening up new avenues for the development of next-generation wearable electromagnetic devices.

Claims

1. A conformal, non-reciprocal, amplitude-phase independently adjustable digitally coded metasurface, characterized in that: The digitally encoded metasurface is composed of 60 × 60 basic units arranged in a periodic manner. Each basic unit is composed of a first ITO-PET film layer (1), a first PMMA dielectric layer (2), a second ITO-PET film layer (3), a second PMMA dielectric layer (4), and a third ITO-PET film layer (5) stacked in sequence. The first ITO-PET film layer (1) is a rectangular strip of ITO processed on a PET substrate by laser processing. The second ITO-PET film layer (3) is a C-shaped pattern of ITO processed on a PET substrate by laser processing. The third ITO-PET film layer (5) is a rectangular strip of ITO processed on a PET substrate by laser processing. The rectangular strip of ITO in the first ITO-PET film layer (1) and the rectangular strip of ITO in the third ITO-PET film layer (5) have the same geometric size. The rectangular strip of ITO in the first ITO-PET film layer (1) coincides with the rectangular strip of ITO in the third ITO-PET film layer (5) after being rotated 90 degrees clockwise. In the second ITO-PET film layer (3), the opening angle of all C-type ITO rings is between -45 degrees and +45 degrees.

2. The conformal non-reciprocal amplitude-phase independently adjustable digitally coded metasurface according to claim 1, characterized in that: The three rectangular ITO strips on the first ITO-PET film layer (1) are 4.5 mm long and 0.5 mm wide, with a spacing of 0.7 mm between them. The geometric dimensions of the rectangular ITO strips on the third ITO-PET film layer (5) are the same as those on the first ITO-PET film layer (1). The rectangular ITO strips of the first ITO-PET film layer (1) are rotated 90 degrees clockwise and then coincide with the rectangular ITO strips of the third ITO-PET film layer (5).

3. The conformal non-reciprocal amplitude-phase independently adjustable digitally coded metasurface according to claim 1, characterized in that: The unit structure uses PMMA as the dielectric substrate, and the metasurface composed of this unit can be bent at an angle between 0 and 180 degrees.

4. The conformal non-reciprocal amplitude-phase independently adjustable digitally coded metasurface according to claim 1, characterized in that: The transmission coefficient can be controlled by changing the opening direction α and the opening size β of the C-type ITO ring in the second ITO-PET film layer (3).

5. The conformal non-reciprocal amplitude-phase independently adjustable digitally coded metasurface according to claim 1, characterized in that: The metasurface is composed of two coding schemes. The first coding scheme is used to control the forward incident linearly polarized electromagnetic waves, and the second coding scheme is used to control the reverse incident linearly polarized electromagnetic waves. The two coding schemes are arranged in an overlapping manner.

6. The conformal non-reciprocal amplitude-phase independently adjustable digitally coded metasurface according to claim 5, characterized in that: In the first encoding scheme, the opening direction and size of the C-shaped ITO ring of the second ITO-PET thin film layer (3) are changed, and the mapping with amplitude and phase is realized, so that the forward-incident linearly polarized electromagnetic wave is effectively modulated; in the second encoding scheme, the opening direction and size of the C-shaped ITO ring of the second ITO-PET thin film layer (3) are changed, and the mapping with amplitude and phase is realized, so that the reverse-incident linearly polarized electromagnetic wave is effectively modulated.

7. The conformal non-reciprocal amplitude-phase independently adjustable digitally coded metasurface according to claim 5, characterized in that: In the first encoding scheme, the long side of the rectangular strip on the first ITO-PET thin film layer (1) is parallel to the X-axis, and the polarization direction of the linearly polarized electromagnetic wave incident in the forward direction is along the Y-axis; in the second encoding scheme, the long side of the rectangular strip on the first ITO-PET thin film layer (2) is parallel to the Y-axis, the polarization direction of the linearly polarized electromagnetic wave incident in the forward direction is along the X-axis, and the working frequency of the electromagnetic wave is 19GHz.

8. The conformal non-reciprocal amplitude-phase independently adjustable digitally coded metasurface according to claim 5, characterized in that: The amplitude and phase design criteria for the C-type ITO ring of the second ITO-PET film layer (3) in the first encoding scheme are as follows: In the formula: focal plane The complex amplitude distribution at point N is given, where N is the number of foci and An is the complex amplitude at the nth foci on the metasurface. , Let be the focal length of the nth focus on the focal plane and the coordinates of the focus's position within the focal plane. y represents the axial position of the conformal metasurface.

9. The conformal non-reciprocal amplitude-phase independently adjustable digitally coded metasurface according to claim 5, characterized in that: The amplitude and phase design criteria for the C-type ITO ring of the second ITO-PET film layer (3) in the second encoding scheme are as follows: In the formula: To generate multi-beam metasurface spatial position The complex amplitude distribution at point N, where N is the number of independent beams, and A n (m,n) represents the spatial position when the nth beam is generated on the metasurface. The amplitude response at that point, When generating the nth beam for the metasurface, the spatial position Phase modulation amount at the location This represents the geometric phase compensation response of the metasurface to an incident linearly polarized electromagnetic wave.

10. The conformal non-reciprocal amplitude-phase independently tunable digitally encoded metasurface according to claim 5, characterized in that: The amplitude and phase design criteria of the unit structure can be mapped to the opening direction and opening size of the C-type ITO ring of the second ITO-PET thin film layer (3). According to the obtained opening direction and opening size, the C-type ITO ring of the second ITO-PET thin film layer (3) on the designed metasurface containing N×N units is arranged in an orderly manner. For linearly polarized electromagnetic waves incident from different directions, the multi-focus focusing function in the near field and the multi-beam generation in the far field are realized on both sides of the designed metasurface. At the same time, the number and intensity of the focus can be controlled independently, and the direction and intensity of the beam are controllable.

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