3D-printed multi-sector multifunctional metasurfaces and design methods

Abstract

The application discloses a 3D printing multi-sector multifunctional metasurface and a design method thereof. The multi-sector multifunctional metasurface is designed based on five polarization multiplexing multifunctional metasurfaces with different phase control means, then the five metasurfaces are respectively faced to five different directions in space and integrated by using a 3D printing technology, and a multi-sector metasurface is formed. Finally, the designed multi-sector metasurface can integrate different electromagnetic functions in five directions in a 3D space. The application designs a polarization multi-sector metasurface based on the 3D printing technology. The polarization multi-sector metasurface can integrate electromagnetic functions of non-common polarization waves on a single device, and can complete wave front control in multiple directions in space, so that the electromagnetic wave control range is expanded from only transmission and reflection to multi-direction control, and the information capacity of the electromagnetic device and the space utilization rate of the wave front control are greatly improved.

Description

Technical Field

[0001] The present invention relates to the field of metasurface electromagnetic control technology, and in particular to a 3D printed multi-sector multifunctional metasurface and a design method thereof. Background Art

[0002] Full-space electromagnetic control is achieved within the transmission and reflection ranges. However, whether it is pure phase control or amplitude-phase modulation, it is difficult to break through multi-dimensional spatial control by relying solely on a single metasurface, and the working polarization state is also limited, making it difficult to meet the needs of more complex electromagnetic environments. More importantly, in practical applications, electromagnetic devices are often required to complete information transmission in as many directions as possible, which requires the designed metasurface to achieve independent control of electromagnetic waves in as many spatial orientations as possible. Due to processing technology limitations, the reported full-space multifunctional metasurface electromagnetic control is limited to the integration of transmission and reflection in a single orientation, making it difficult to achieve multi-directional electromagnetic control in 3D space. Summary of the Invention

[0003] The present invention discloses a 3D printed multi-sector multifunctional metasurface, wherein the 3D printed multi-sector multifunctional metasurface comprises azimuthal surfaces of first to fifth sectors;

[0004] Each azimuth surface includes a multifunctional metasurface, and the multifunctional metasurface of each azimuth surface includes the first to fifth metal structure layers, the first to fourth ABS dielectric layers, and the first to fifth F4B dielectric plates;

[0005] The first to fourth metal structures are identical cross-shaped metal structures, and the fifth metal structure is a metal plate with circular grooves. The first to fourth metal structures are respectively disposed on the first to fourth F4B dielectric plates, and the first to fourth metal structures and the first to fourth F4B dielectric plates are separated by the first to fourth ABS dielectric layers, respectively. The fifth metal structure is disposed at the bottom of the fifth F4B dielectric plate, and the fifth metal structure and the fifth F4B dielectric plate are separated from the top cascaded first to fourth metal structures by the fourth ABS dielectric layer.

[0006] The width of the cross-shaped metal structure is w, and the length in the x direction of the cross-shaped metal structure is l. x , the length in the y direction is l y , by changing the structural parameter l x and l y The transmission phase can be controlled under the incidence of two orthogonal linear polarization waves;

[0007] The circular groove of the metal plate with the circular groove has a radius of r and a width of g.

[0008] Furthermore, the two orthogonal linear polarization channels in the first sector are designed with three-beam radiation and double vortex beam generation functions respectively;

[0009] The second sector realizes the independent control function of two orthogonal rotational waves based on the rotational decoupling theory;

[0010] The third sector realizes the vortex beam generation function with mode number l=-2 based on the PB phase;

[0011] The fourth sector realizes the dual functions of co-polarization and cross-polarization decoupling under LCP wave incidence;

[0012] The fifth sector realizes the decoupling and control function of the co-polarized wave and the cross-polarized wave under the incidence of the RCP wave.

[0013] Furthermore, the azimuth planes of the first to fifth sectors respectively determine the functional phase distribution according to the function, and determine the transmission phase of the two orthogonal linear polarization waves according to the phase distribution. and and the geometric phase α;

[0014] And according to the transmission phase and Calculate the corresponding structural parameter l x and l y , and output the structural parameters l x and l y .

[0015] A method for designing a 3D printed multi-sector multifunctional metasurface is also provided. The method for designing a 3D printed multi-sector multifunctional metasurface comprises the following steps:

[0016] Step 1, designing a transmissive anisotropic unit with high transmittance and full-cycle phase coverage;

[0017] Step 2: Determine the structural parameter l in the transmission anisotropic unit x and l y ;

[0018] Step 3: Design the functions of the first to fifth sectors respectively.

[0019] Furthermore, in step 2, the following steps are also included:

[0020] Step 21: Determine the functional phase distribution according to the specific electromagnetic function in each polarization channel, and determine the transmission phase of the two orthogonal linear polarization waves according to the phase distribution. and and the geometric phase α = 2θ, where θ represents the unit rotation angle;

[0021] Step 22, traversing each structure parameter corresponding to the transmission phase in the established 2D structure unit database and and calculating the error δ of and ;

[0022] Step 23, if the calculated δ meets the error requirement, output l x and l y , otherwise, increase the variable of and respectively, and re-cycle steps 22-23 to gradually approach the target value.

[0023] Further, in step 3, the following steps are further included:

[0024] Step 31, three-beam radiation and double-vortex beam generation functions are respectively designed in the two orthogonal linear polarization channels of the first sector;

[0025] Step 32, the independent control function of two orthogonal rotational waves is realized in the second sector based on the rotational decoupling theory;

[0026] Step 33, vortex beam generation function with mode number l = -2 is designed in the third sector super surface based on PB phase;

[0027] Step 34, the co-polarization and cross-polarization decoupling double function of LCP wave in the fourth sector;

[0028] Step 35, the fifth sector has the co-polarization and cross-polarization decoupling control function under RCP wave incidence.

[0029] Further, in step 31, the three-beam radiation phase distribution is:

[0030]

[0031] In the formula, represents the unit phase at position (m, n) in the super surface, represents the phase distribution of the i-th beam, θ0 represents the beam elevation angle, represents the beam azimuth angle, ψ represents the initial phase, k0 is the free space wave number, S m,n is the distance of the (m, n) unit in the feed surface from the super surface, x m,n and y m,n represent the distance of the (m, n) unit from the x-axis and y-axis respectively;

[0032] The phase distribution of the vortex beam is:

[0033]

[0034] Where l = 1 represents the mode number of the vortex beam, x m,n and y m,n Represents the distance of the (m, n)th unit from the x-axis and y-axis respectively.

[0035] Furthermore, in step 32, the independent control functions of the two orthogonal hand-direction waves are:

[0036] Under RCP wave incidence, high-gain, low-sidelobe single-beam radiation is achieved, and under LCP wave incidence, beam deflection function is realized. The phase distribution of each function, the corresponding transmission phase and geometric phase are:

[0037]

[0038] represents the co-polarization phase under x-polarized wave incidence, represents the co-polarization phase under the incidence of y-polarized wave, represents the functional phase of the cross-polarization channel under the incidence of right-hand circularly polarized wave, It represents the functional phase of the cross-polarization channel under the incidence of left-hand circularly polarized wave, α is the geometric phase, the geometric phase α = 2θ, and θ represents the unit rotation angle.

[0039] Furthermore, in step 34, when the fourth sector is incident with the LCP wave, the transmission coefficients of the co-polarized and cross-polarized outgoing waves of the metasurface are:

[0040]

[0041] r RL represents the cross-polarization coefficient under left-hand circularly polarized wave incidence, r LL represents the co-polarization coefficient under left-hand circularly polarized wave incidence; the corresponding transmission phase and geometric phase are further derived as:

[0042]

[0043] represents the functional phase of the cross-polarization channel under left-hand circular polarization incidence, It represents the phase corresponding to the co-polarization channel function under the incidence of left-hand circularly polarized wave, represents the phase difference, represents the co-polarization phase under x-polarized wave incidence, represents the co-polarization phase under the incidence of y-polarized wave, α is the geometric phase, the geometric phase α = 2θ, and θ represents the unit rotation angle.

[0044] Furthermore, in step 35, when the fifth sector is incident with the RCP wave, the transmission coefficients of the co-polarized and cross-polarized outgoing waves of the metasurface are:

[0045]

[0046] r LR represents the cross-polarization coefficient under right-hand circularly polarized wave incidence, r RR represents the co-polarization coefficient under right-hand circularly polarized wave incidence, and the corresponding transmission phase and geometric phase are further derived as:

[0047]

[0048] It represents the phase corresponding to the co-polarization channel function under the incidence of right-hand circularly polarized wave, represents the phase difference, represents the co-polarization phase under x-polarized wave incidence, represents the co-polarization phase under the incidence of y-polarized wave, α is the geometric phase, the geometric phase α = 2θ, and θ represents the unit rotation angle.

[0049] The beneficial effects achieved by the present invention are:

[0050] The present invention designs a polarized multi-sector metasurface based on 3D printing technology. The invented polarized multi-sector metasurface can integrate the electromagnetic functions of non-co-polarized waves on a single device and complete wavefront control in multiple directions in space, expanding the electromagnetic wave control range from only transmission and reflection to multi-directional control, greatly improving the information capacity of electromagnetic devices and the spatial utilization of wavefront control.

[0051] The present invention completes the integrated design of multi-sector integration, realizes the multi-sector multi-functional independent control of polarization multiplexing, further improves the multi-functional metasurface information capacity and electromagnetic control coverage, and has important application prospects in the future communication field.

[0052] The present invention introduces 3D printing technology into metasurface design, completing the integrated design of a multi-sector metasurface with five sectors. To meet the control needs of non-co-polarized waves and adapt to more complex electromagnetic environments, the metasurface of the five sectors respectively adopts the transmission phase control theory based on orthogonal linear polarization waves, the rotational decoupling theory, the PB phase theory, and the co-polarization and cross-polarization wave decoupling control theory of circularly polarized waves to complete the multifunctional electromagnetic control of polarization multiplexing. To achieve the above electromagnetic control, a multi-layer metal structure cascade transmission anisotropic unit is first designed. Then, the non-co-polarized wave control method is derived based on the transmission phase and geometric phase. Finally, based on the designed unit and the above theory, the polarization multi-sector multifunctional metasurface design is completed. Under the excitation of a non-co-polarized feed source, the designed multi-sector metasurface can realize the functions of three-beam radiation of non-co-polarized waves, dual vortex beam generation, single beam radiation, beam deflection, dual beam radiation and vortex beam generation with different mode numbers in five different directions in space. The invented polarized multi-sector metasurface can integrate the electromagnetic functions of non-co-polarized waves on a single device, and complete wavefront control in multiple directions in space, expanding the range of electromagnetic wave control from only transmission and reflection to multi-directional control, greatly improving the information capacity of electromagnetic devices and the spatial utilization of wavefront control. BRIEF DESCRIPTION OF THE DRAWINGS

[0053] Figure 1 This is a functional schematic diagram of a multi-sector multifunctional metasurface provided in an embodiment of the present invention;

[0054] Figure 2 A diagram showing the unit structure of a multi-sector multifunctional metasurface provided in an embodiment of the present invention, (a) the overall structure of the unit; (b) the first to fourth metal layers; (c) the fifth metal layer;

[0055] Figure 3 Transmission amplitude and phase of the multi-sector multifunctional metasurface with different structural parameter units at 11.3 GHz provided in an embodiment of the present invention; (a) Transmission phase under x-polarized wave incidence and (b) transmission amplitude (c) Transmission phase under y-polarized wave incidence and (b) transmission amplitude

[0056] Figure 4 Surface current distribution of a unit cell at 11.3 GHz for a multi-sector multifunctional metasurface provided in an embodiment of the present invention; (a) Surface current distribution of each metal layer; (b) Surface current distribution of the first to fourth metal layers; (c) Surface current distribution of the fifth metal layer;

[0057] Figure 5 A two-dimensional parameter scanning solution for a multi-sector multifunctional metasurface provided in an embodiment of the present invention;

[0058] Figure 6 The sample preparation process of the multi-sector multifunctional metasurface provided in the embodiment of the present invention; (a) ABS engineering resin; (b) flexible metasurface; (c) multi-sector metasurface sample;

[0059] Figure 7 Functional phase distribution of the multi-sector multifunctional metasurface provided in an embodiment of the present invention; (a) three-beam radiation functional phase distribution; (b) dual vortex beam functional phase distribution;

[0060] Figure 8 3D far-field electric field simulation results at 10.5, 11, 11.3, and 11.5 GHz for the multi-sector multifunctional metasurface provided in an embodiment of the present invention under excitation by an x-polarized feed source;

[0061] Figure 9 The multi-sector multifunctional metasurface provided in the embodiment of the present invention is excited by an x-polarized feed source. Normalized far-field electric field simulation results within the plane;

[0062] Figure 10 The multi-sector multifunctional metasurface provided in the embodiment of the present invention is excited by an x-polarized feed source. Normalized far-field electric field simulation results within the plane;

[0063] Figure 11 The multi-sector multifunctional metasurface provided in the embodiment of the present invention is excited by an x-polarized feed source. Normalized far-field electric field test results within the plane;

[0064] Figure 12 The multi-sector multifunctional metasurface provided in the embodiment of the present invention is excited by an x-polarized feed source. Normalized far-field electric field test results within the plane;

[0065] Figure 13 3D far-field electric field simulation results at 10.5, 11, 11.3, and 11.5 GHz for the multi-sector multifunctional metasurface provided in an embodiment of the present invention under y-polarized feed excitation;

[0066] Figure 14 The simulation and test results of the normalized radiation field at 10.5, 11, 11.3, and 11.5 GHz for the multi-sector multifunctional metasurface provided in an embodiment of the present invention under y-polarized feed excitation;

[0067] Figure 15Phase distribution and unit rotation angle of the multi-sector multifunctional metasurface provided in an embodiment of the present invention; (a) phase distribution of single-beam radiation function; (b) phase distribution of beam deflection function; (c) co-polarized wave transmission phase under x-polarized wave incidence; (d) co-polarized wave transmission phase under y-polarized wave incidence; (e) unit rotation angle;

[0068] Figure 16 3D far-field electric field simulation results at 10.5, 11, 11.3, and 11.5 GHz for the multi-sector multifunctional metasurface provided in an embodiment of the present invention under RCP feed excitation;

[0069] Figure 17 The 2D far-field electric field simulation and test results of the multi-sector multifunctional metasurface provided in an embodiment of the present invention under RCP feed excitation at 10.5, 11, 11.3, and 11.5 GHz;

[0070] Figure 18 The 3D far-field electric field simulation results of the multi-sector multifunctional metasurface provided in an embodiment of the present invention under LCP feed excitation at 10.5, 11, 11.3, and 11.5 GHz;

[0071] Figure 19 The multi-sector multifunctional metasurface provided in the embodiment of the present invention is excited by the LCP feed source. In-plane 2D far-field electric field simulation and test results;

[0072] Figure 20 3D far-field electric field simulation results at 10.5, 11, 11.3, and 11.5 GHz for the multi-sector multifunctional metasurface provided in an embodiment of the present invention under RCP feed excitation;

[0073] Figure 21 The xoy-in-plane near-field electric field simulation results of the multi-sector multifunctional metasurface provided in an embodiment of the present invention under RCP feed excitation at 10.5, 11, 11.3, and 11.5 GHz;

[0074] Figure 22 The xoy-in-plane near-field electric field test results of the multi-sector multifunctional metasurface provided in an embodiment of the present invention under RCP feed excitation at 10.5, 11, 11.3, and 11.5 GHz;

[0075] Figure 23 The xoy-in-plane phase distribution test results of the multi-sector multifunctional metasurface provided in an embodiment of the present invention under RCP feed excitation at 10.5, 11, 11.3, and 11.5 GHz;

[0076] Figure 243D far-field electric field simulation results of RCP waves at 10.5, 11, 11.3, and 11.5 GHz for the multi-sector multifunctional metasurface provided in an embodiment of the present invention under LCP feed excitation;

[0077] Figure 25 The near-field simulation results of xoy-in-plane RCP waves at 10.5, 11, 11.3, and 11.5 GHz for the multi-sector multifunctional metasurface provided in an embodiment of the present invention under LCP feed excitation.

[0078] Figure 26 The near-field test results of xoy-in-plane RCP waves at 10.5, 11, 11.3, and 11.5 GHz for the multi-sector multifunctional metasurface provided in an embodiment of the present invention under LCP feed excitation;

[0079] Figure 27 The xoy-in-plane RCP wave phase test results at 10.5, 11, 11.3, and 11.5 GHz for the multi-sector multifunctional metasurface provided in an embodiment of the present invention under LCP feed excitation;

[0080] Figure 28 3D far-field electric field simulation results of LCP waves at 10.5, 11, 11.3, and 11.5 GHz for the multi-sector multifunctional metasurface provided in an embodiment of the present invention under LCP feed excitation;

[0081] Figure 29 The near-field simulation results of xoy-in-plane LCP waves at 10.5, 11, 11.3, and 11.5 GHz for the multi-sector multifunctional metasurface provided in an embodiment of the present invention under LCP feed excitation;

[0082] Figure 30 The near-field test results of xoy-in-plane LCP waves at 10.5, 11, 11.3, and 11.5 GHz for the multi-sector multifunctional metasurface provided in an embodiment of the present invention under LCP feed excitation;

[0083] Figure 31 The xoy-in-plane LCP wave phase test results at 10.5, 11, 11.3, and 11.5 GHz for the multi-sector multifunctional metasurface provided in an embodiment of the present invention under LCP feed excitation;

[0084] Figure 32 3D far-field electric field simulation results of LCP waves at 10.5, 11, 11.3, and 11.5 GHz for the multi-sector multifunctional metasurface provided in an embodiment of the present invention under RCP feed excitation;

[0085] Figure 33The 2D far-field electric field simulation and test results of LCP waves of the multi-sector multifunctional metasurface provided in the embodiment of the present invention under the excitation of the RCP feed source;

[0086] Figure 34 3D far-field electric field simulation results of RCP waves at 10.5, 11, 11.3, and 11.5 GHz for the multi-sector multifunctional metasurface provided in an embodiment of the present invention under RCP feed excitation;

[0087] Figure 35 2D far-field electric field simulation and test results of RCP waves under RCP feed excitation of the multi-sector multifunctional metasurface provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0088] The present invention will be further described below with reference to specific embodiments, and the advantages and features of the present invention will become clearer as the description proceeds. However, these embodiments are merely exemplary and do not constitute any limitation to the scope of the present invention.

[0089] Example 1

[0090] As attached Figure 1 As shown, the present invention discloses a 3D printed multi-sector multifunctional metasurface, which has five different azimuthal surfaces, named as the first to fifth sectors in sequence. A feed source radiating non-co-polarized waves is placed in the central area surrounded by the five sectors. The first to fifth sectors have the same size, the angles between adjacent sectors are also the same, and the distances from the central feed source are the same.

[0091] After being manipulated by the five-sector metasurface, electromagnetic waves are radiated in five different azimuth regions in 3D space, significantly improving their coverage. Furthermore, to meet the control requirements for non-co-polarized waves, the five sectors implement different electromagnetic functions in non-co-polarized channels based on different phase control principles. The first sector implements three-beam radiation and dual-vortex beam generation based on the transmission phase under two orthogonal linearly polarized wave incidences. The second sector implements high-gain, low-sidelobe single-beam radiation and beam deflection based on the chirality decoupling theory in two orthogonal chirality channels. The third sector implements vortex beam generation with a mode number of l = -2 based on the PB phase. Under LCP wave incidence, the fourth sector implements vortex beam generation with l = 1 and l = 2 based on the decoupling control of co-polarized and cross-polarized waves. Under RCP wave incidence, the fifth sector implements dual-beam generation in two orthogonal planes based on the decoupling control of co-polarized and cross-polarized waves.

[0092] In order to realize the above multi-sector multifunctional metasurface, it is first necessary to design a transmissive anisotropic unit with high transmittance and full-period phase coverage. The transmissive anisotropic unit is square and has a period of P. Figure 2 As shown in (a), the designed metasurface unit consists of 5 layers of cascaded metal structures, 4 layers of ABS engineering resin medium and 5 layers of F4B ultra-thin medium. Figure 2 As shown in (b), the first to fourth metal structures of the top layer are identical cross-shaped metal structures, which are respectively placed on the first to fourth F4B dielectric plates with a thickness of h3. The dielectric constant of the F4B dielectric plate is 2.65 and the electric tangent loss value is 0.001. The fifth metal structure is a metal plate with circular grooves ( Figure 2 (as shown in (c)), the inner diameter of the circular groove is r and the width is g. The fifth metal structure is separated from the first to fourth metal structures of the top cascade by the fifth ABS dielectric layer with a thickness of h1, and the first to fourth metal structures are separated by the first to fourth ABS dielectric layers with a thickness of h2, respectively, where the dielectric constant of the ABS material is 2.7 and the electric tangent loss value is 0.005. The use of multi-layer cascaded metal structures can improve the phase coverage range of the metasurface unit. The bottom slotted metal plate structure and the top cascaded cross-shaped metal structure together constitute the FP resonant cavity, which further increases the transmittance of the metasurface unit. When the electromagnetic wave is incident along the +z direction, by changing the unit size l along the x direction x and the unit size l along the y direction y The parameters can realize the transmission phase control under the incidence of two orthogonal linear polarization waves.

[0093] In one embodiment, the structural parameter values ​​of the metasurface unit are:

[0094] h1 is 1.7mm, h2 is 1mm, h3 is 0.2mm, w is 1mm, g is 0.9mm, p is 9mm, and r is 3.5mm.

[0095] After the optimization design of the metasurface unit was completed, the CST (2018) electromagnetic simulation software was used to study its transmission amplitude and phase response. During the simulation, the designed metasurface unit was excited by x- and y-polarized waves, and the structure parameters l were changed. x and l y Obtain the transmission amplitude and phase. First, as Figure 3 As shown in (a), under the incident x-polarized wave, when the structural parameter l x When the length changes from 4mm to 8mm, the unit transmits the phase at 11.3GHz. A change from 0 to 2π is achieved. At the same time, the structural parameter l y The change of the transmission phase The effect produced is almost negligible, proving that the metasurface unit has excellent birefringence effect. Figure 3 In (b), the transmission amplitude under different structural parameters All are kept above 0.8. Using the same method, Figure 3 As shown in (c), under the y-polarized wave incident, when the structural parameter l y When the transmission phase changes from 4mm to 8mm, Achieved full phase coverage of 2π, and It will not follow l x changes with the change of , proving the isolation of polarization. Figure 3 As shown in (d), the transmission amplitude The above simulation results show that the metasurface unit can achieve 2π full phase coverage in the co-polarization channel under the incidence of orthogonal linearly polarized waves, while maintaining a transmittance above 0.8 and good polarization isolation, laying the foundation for the subsequent design of multi-polarization control metasurfaces.

[0096] The working mechanism of the unit is studied by simulating the surface current of the metasurface unit. During the simulation, the designed metasurface unit is excited by RCP wave. The simulation results are shown in Figure 2. Figure 4 As shown in (a), each layer of the metal structure has a surface current distributed, proving that the designed unit achieves the ultimate phase control through the joint action of each layer of metal. Figure 4 Figures (b) and (c) show the surface currents of the cross-shaped metal structure and the circular groove metal floor structure, respectively. The simulation results clearly show that the surface currents converge at the edges of the cross-shaped metal structure and the circular groove, respectively. This demonstrates that the first to fourth metal layers of the top cascade, along with the fifth metal layer, together form a resonant structure, resulting in high transmittance and wide phase coverage.

[0097] Example 2

[0098] The present invention also provides a design method for a 3D-printed multi-sector multifunctional metasurface. The designed metasurface consists of five sectors, each of which adopts a different phase control mechanism. The method specifically includes the following steps:

[0099] Step 1, designing a transmissive anisotropic unit with high transmittance and full-cycle phase coverage;

[0100] In this embodiment, the transmission anisotropic unit structure adopts the unit described in the first embodiment.

[0101] Step 2: Determine the structural parameter l in the transmission anisotropic unit x and l y ;

[0102] The metasurface design method based on transmission phase and geometric phase has been mature. This paper will focus on the design method of metasurface for decoupling control between different circularly polarized channels. Since the decoupling control of non-co-polarized waves involves transmission phase and geometric phase, it is necessary to perform two-dimensional structural parameter scanning. The design difficulty and complexity are much higher than one-dimensional structural parameter scanning. Therefore, in order to find the two-dimensional structural parameter more accurately and conveniently, x and l y , this paper summarizes the Figure 5 The two-dimensional parameter scanning scheme shown in the figure specifically includes the following steps:

[0103] Step 21, before finding the structural parameters of each unit in the metasurface, first determine the functional phase distribution according to the specific electromagnetic function in each polarization channel, and then determine the transmission phase of the two orthogonal linear polarization waves according to the phase distribution and And the geometric phase α=2θ, where θ represents the unit rotation angle.

[0104] Step 22: traverse the transmission phase corresponding to each structural parameter in the established 2D structural unit database. and And calculate with and The error δ.

[0105] Step 23: If the calculated δ meets the error requirement, output l x and l y Otherwise, and Increase variable A respectively and recycle steps 22-23 to gradually approach the target value.

[0106] In this embodiment, five metasurfaces consisting of 27×27 units were designed in sequence, and then the five metasurfaces were integrated into one design using 3D printing technology. The production process and the final multi-sector metasurface sample are shown in Figure 2. Figure 6 First, a 3D printer was used to print an integrated framework with five sectors. Then, multi-layer dielectric plates were printed separately, and a flexible metasurface with a metal structure was processed using PCB technology. Finally, each layer of dielectric plate and metasurface were assembled together to form the final multi-sector metasurface sample.

[0107] Step 3, design the functions of the first to fifth sectors respectively;

[0108] The specific steps include:

[0109] In step 31, three-beam radiation and double-vortex beam generation functions are designed in the two orthogonal linear polarization channels of the first sector, and simulation and experimental verification are carried out.

[0110] Under the excitation of x-polarized feed, the three beams are pointed as follows: (30°, 90°) and (-30°, 0°). Its phase distribution can be calculated by the following formula:

[0111]

[0112] Formula (1) shows that the final three-beam radiation function phase comes from the complex superposition of each beam phase. represents the unit phase at position (m,n) in the metasurface, represents the phase distribution of the i-th beam, θ0 represents the beam pitch angle, represents the beam azimuth, which is obtained by formula (2), ψ represents the initial phase, k0 is the free space beam, S m,n is the distance between the feed source and the unit at the (m, n)th position in the metasurface.

[0113] In this design, the feed is placed at a distance of F = 146 mm from the center of the metasurface. m,n and y m,n Represent the distance of the (m, n)th unit from the x-axis and y-axis respectively. According to formulas (1) and (2), the phase distribution of each beam and the final metasurface phase distribution are calculated as follows: Figure 7 As shown in (a). The phase distribution of the vortex beam can be obtained by the following formula:

[0114]

[0115] Where l = 1 represents the mode number of the vortex beam. Due to the feed source excitation, the vortex beam phase is directly superimposed on the calculated direction. The phase distribution of the two beams in the direction of (-30°, 0°) is obtained by complex superposition. The final phase distribution of the double vortex beam is as follows: Figure 7 As shown in (b).

[0116] After completing the design of the first sector metasurface based on the above phase distribution, we used simulation and experiments to study its performance. First, we used a feed source that radiated x-polarized waves to excite the designed metasurface. The 3D far-field simulation results Figure 8 As shown in the simulation results, it can be seen that in the range of 10.5 to 11.5 GHz, the metasurface achieves directional radiation of beams in three target directions, and the gain at the operating frequency of 11.3 GHz reaches 18.7 dB. Although at θ0 = 30°, The sidelobe level in the direction is relatively high, but still more than 10dB lower than the main beam. This phenomenon will be confirmed in the following 2D far-field electric field simulation results. To further verify its performance, we calculated The 2D far-field electric field of the two surfaces at 90° and 90° are as follows: Figure 9 and Figure 10 As shown. Figure 9 As shown in the simulation results of the normalized far-field electric field, it can be clearly seen that In the 2D plane, beams pointing to the directions of θ0 = -30° and 30° appear, which is consistent with the 3D far-field simulation results. Figure 10 The simulation results show that in Only a single main beam appears in the 2D cross-section, fully consistent with design expectations. Furthermore, in all 2D far-field electric field simulation results, the sidelobe levels are more than 10 dB lower than the main beam, and the electric field of the cross-polarized wave is more than 20 dB lower than that of the co-polarized wave.

[0117] After the simulation is completed, the metasurface sample is experimentally verified. The metasurface sample is placed in the center of the turntable, and a linearly polarized feed source operating at 6 to 18 GHz is placed in the center of the sample. A linearly polarized horn antenna operating at 2 to 18 GHz is placed at the end of the mechanical rotating arm as a receiving antenna. The feed source and the receiving antenna are respectively connected to the two ports of the vector network analyzer through microwave cables for transmitting and receiving electromagnetic wave signals. The 2D electric field test results in the two orthogonal planes are shown as follows: Figure 11 and Figure 12 As shown. From the test results, it can be clearly seen that Two main beams appear in the target direction within the plane, and A single beam appeared in the target direction within the plane, and the sidelobe level was more than 10dB lower than the main beam, and the electric field of the cross-polarized wave was more than 20dB lower than the main polarized wave, which was completely consistent with the simulation results, and strongly proved that the first-sector metasurface can achieve three-beam radiation function under the incidence of x-polarized waves.

[0118] After completing the characterization of the three-beam radiation performance under x-polarized wave incidence, the same method was used to verify the dual vortex beam generation function under y-polarized wave incidence. In the simulation process, the designed metasurface was excited by the feed antenna radiating y-polarized wave, and the far-field electric field distribution of the metasurface was obtained by setting a far-field monitor. Among them, the 3D far-field electric field simulation results are shown in Figure 2. Figure 13 As shown in the simulation results, it can be clearly seen that in the frequency range of 10.5GHz to 11.5GHz, the two vortex beams point to the space. and (-30°, 0°) directions, which is completely consistent with the design expectations. Next, the 2D far-field electric field performance of the metasurface is characterized by simulation and experiment respectively. The experimental setup is still the same as before, the only difference is that the feed polarization and the receiving antenna polarization are changed to y-polarization. The comparison results of simulation and test are shown in Figure 2. Figure 14 As shown, the simulation results agree well with the test results. The zero depth occurs at θ0 = 30° and -30°, fully consistent with the theoretical design. Furthermore, the electric field level in the surrounding sidelobes is more than 10 dB lower than that in the main beam, strongly demonstrating the correctness of the design. The discrepancy between the simulation and test results is primarily due to processing errors introduced during 3D printing and sample assembly, as well as the influence of the experimental environment.

[0119] The above simulation and experimental results prove that the designed first-sector metasurface can realize three-beam radiation and dual-vortex beam generation functions based on transmission phase control under the incidence of orthogonal linear polarization waves.

[0120] In step 32, the second sector realizes the independent control function of two orthogonal rotational waves based on the rotational decoupling theory.

[0121] Among them, high-gain low-sidelobe single-beam radiation is completed under RCP wave incidence, and beam deflection function is realized under LCP wave incidence. According to the phase distribution of each function ( and ), the corresponding transmission phase ( and ) and the geometric phase (α) can be calculated using the following rotational decoupling formula:

[0122]

[0123] represents the co-polarization phase under x-polarized wave incidence, represents the co-polarization phase under the incidence of y-polarized wave, represents the functional phase of the cross-polarization channel under the incidence of right-hand circularly polarized wave, It represents the functional phase of the cross-polarization channel under the incidence of left-hand circularly polarized wave.

[0124] The calculation results are as follows Figure 15 shown.

[0125] According to the above phase distribution, the second sector metasurface was designed and simulated and experimentally verified. The designed metasurface model was simulated in the time domain using the CST (2018) electromagnetic simulation software. In the simulation setting, the RCP feed source was used to excite the metasurface, and the far-field electric field results at different frequencies were obtained by setting a far-field monitor. Figure 16As shown in Fig. 11, from the 3D far-field simulation results, it can be seen that the electromagnetic wave emitted by the RCP feed source realizes low-sidelobe high-gain radiation after being regulated by the metasurface, and its gain reaches 25.3 dB at 11.3 GHz. To further prove its function, the far-field electric field in the 2D plane is simulated and tested respectively. The experimental setup is still as before, and the RCP feed source is used to excite the metasurface, while the LCP wave horn antenna is used as the receiving antenna. As shown in Fig. 12, the simulation and test results are in good agreement, and the sidelobe level is more than 10 dB lower than the main beam, which powerfully proves that the designed metasurface can realize high-gain low-sidelobe beam radiation under RCP wave incidence. Figure 17

[0126] Next, the beam deflection function under LCP wave incidence is simulated and experimentally verified. Here, the deflection direction of the beam is preset to θ0=-30°, The 3D far-field simulation results are shown in Fig. 15. Figure 18 As shown in Fig. 15, a pen-shaped tilted beam accurately points to the target direction, and the gain reaches 24.5 dB. At the same time, from the normalized far-field electric field simulation and test results in Fig. 16, Figure 19 In the 2D plane of Fig. 16, the main beam appears in the direction of θ0=-30°, and the sidelobe level is 10 dB lower than the main beam, which powerfully verifies the beam deflection function under LCP wave incidence.

[0127] The above simulation and test results prove that the second sector metasurface realizes independent wavefront regulation under RCP wave and LCP wave incidence respectively, which has important application in polarization multiplexing multifunctional metasurfaces.

[0128] Step 33, the vortex beam generation function of mode number l=-2 in the third sector metasurface is designed based on the PB phase, and its performance is verified by simulation and experiment.

[0129] The vortex beam generation function of mode number l=-2 in the third sector metasurface is designed based on the PB phase, and the calculation process is the same as that in step 32, by solving the phase distribution and determining the corresponding structure parameters and unit rotation angle.

[0130] The 3D far-field simulation results are shown in Fig. 19. Figure 20 As can be clearly seen from the simulation results, an ideal vortex beam is generated around the working frequency of 11.3 GHz. Figure 21 The near-field simulation results in Fig. 20 also show that a "donut" shaped electric field distribution appears in the xoy-plane at a distance of z=120 mm from the metasurface, which is completely consistent with the characteristics of the vortex beam.

[0131] ​​Next, the performance of the metasurface was further verified by testing its near-field distribution. A feed source radiating RCP waves was placed at the center of the sample, and a probe was placed 120 mm away from the metasurface. The probe was placed on a 240×240 mm 2 The near-field electric field test results are shown in Figure 1. Figure 22 As shown in the figure, the test results show a "donut"-shaped electric field distribution that is consistent with the simulation results, proving the vortex beam generation function. In addition, Figure 23 The results of the phase distribution test show that the two vortex arms rotate counterclockwise, proving that the mode number of the vortex beam is l = -2. The above simulation and test results show that the designed third-sector metasurface can achieve the l = -2 vortex beam generation function based on the PB phase control mechanism.

[0132] Step 34, dual functions of co-polarization and cross-polarization decoupling of LCP waves in the fourth sector;

[0133] Under LCP wave incidence, the transmission coefficients of the co-polarized and cross-polarized outgoing waves of the metasurface can be expressed by the following formula:

[0134]

[0135] r RL represents the cross-polarization coefficient under left-hand circularly polarized wave incidence, r LL represents the co-polarization coefficient under the incidence of left-hand circularly polarized wave.

[0136] According to the above formula, when the functional phase distribution of each channel is known, and Afterwards, the corresponding transmission phase and geometric phase expressions can be further derived:

[0137]

[0138] represents the functional phase of the cross-polarization channel under left-hand circular polarization incidence, It represents the phase corresponding to the co-polarization channel function under the incidence of left-hand circularly polarized wave, Indicates the phase difference.

[0139] The function in the cross-polarization channel is designed as a vortex beam with l = 2, while the function in the co-polarization channel is designed as a vortex beam with l = 1. All functions are excited by a feed source, and the distance between the feed source and the metasurface is 146 mm. The corresponding transmission phase and geometric phase distribution are calculated using formula (7), and according to Figure 5 The metasurface design process shown completes the metasurface design.

[0140] After completing the metasurface design, the CST (2018) electromagnetic simulation software was used to perform time domain simulation calculations of the electromagnetic functions in the cross-polarization channel. Figure 24 The 3D far-field simulation results in show that under the incidence of LCP waves, the transmitted RCP waves form vortex beams. Figure 25 The near-field simulation results in

[15] further demonstrate the functionality of the designed vortex beam. Figure 26 The near-field electric field test results in the simulation are in good agreement with the results obtained in Figure 27 Two clockwise rotating vortex arms appeared in the phase distribution test results, which strongly proved that the l=2 vortex beam was realized in the cross-polarization channel.

[0141] The vortex beam function with l=1 in the co-polarization channel is verified. Figure 28 The 3D simulation results in the figure show that under the incident LCP wave, the transmitted LCP wave forms a vortex beam, and its diameter is smaller than that of the vortex beam when l=2, which is consistent with the expected effect. Figure 29 The near-field simulation results in the figure also agree with the vortex beam characteristics of l = 1. The vortex beam performance in the co-polarization channel is tested, and the performance is characterized by calculating the LCP wave amplitude and phase in the co-polarization channel. The electric field distribution test results are shown in Figure 2. Figure 30 As shown in the figure, a "donut"-shaped electric field distribution phenomenon appears in the xoy-plane, which is consistent with the vortex beam function and is in good agreement with the corresponding electric field simulation results. At the same time, the "donut" diameter is smaller than the vortex beam diameter of l = 2, which is consistent with the vortex beam characteristics of l = 1. To further verify the vortex beam performance, the phase distribution results in the xoy-plane are given. Figure 31 A clear vortex arm can be seen in the phase distribution results shown, which is completely consistent with the vortex beam function with l = 1. In summary, all the above simulation and experimental results prove that the fourth-sector metasurface can achieve decoupling control of co-polarized waves and cross-polarized waves under LCP wave incidence.

[0142] Step 35: The fifth sector performs a decoupling control function on the co-polarized wave and the cross-polarized wave under the incidence of the RCP wave.

[0143] Under RCP wave incidence, the transmission coefficients of the co-polarized and cross-polarized outgoing waves of the metasurface can be expressed by the following formula:

[0144]

[0145] r LR represents the cross-polarization coefficient under right-hand circularly polarized wave incidence, r RR represents the co-polarization coefficient under the incidence of right-hand circularly polarized wave.

[0146] According to the above formula, when the functional phase distribution of each channel is known, and Afterwards, the corresponding transmission phase and geometric phase expressions can be further derived:

[0147]

[0148] It represents the phase corresponding to the co-polarization channel function under the incidence of right-hand circularly polarized wave.

[0149] The function of the cross-polarization channel is designed to be dual-beam radiation in the xoz-plane, while the function of the co-polarization channel is dual-beam radiation in the yoz-plane. The beams in both polarization channels are pointed in the directions of θ0 = 30° and -30°, and both are excited by feed sources, which are 146 mm away from the metasurface. The corresponding transmission phase and geometric phase distribution are calculated using formula (10), and according to Figure 5 The metasurface design process shown completes the metasurface design.

[0150] After completing the metasurface design, we first simulated and experimentally verified the dual-beam radiation function in the cross-polarization channel. Under the excitation of the RCP feed, the 3D far-field simulation results of the LCP wave are as follows: Figure 32 As shown in Figure 2, two obvious main beams appear in the target direction in the xoz-plane, and their gain reaches 21.9dB at the operating frequency. In addition, the dual-beam radiation function under the cross-polarization channel is also Figure 33 This is confirmed by the 2D electric field simulation and test results in .

[0151] Finally, the same method is used to verify the dual-beam radiation function in the co-polarization channel. The 3D far-field simulation results of RCP waves are shown in Figure 2. Figure 34 As shown, main beams pointing to θ0 = 30° and -30° directions appeared in the yoz-plane, and the gain at the operating frequency of 11.3 GHz reached 21.9 dB. Figure 35 The 2D far-field electric field simulation and test results further show that the co-polarized wave in the yoz-plane achieves highly directional dual-beam radiation, and the electric field level in the xoz-plane is much lower than the main beam in the yoz-plane by more than 10dB, proving the correctness of the design.

[0152] The above simulation and test results prove that the fifth-sector metasurface can achieve decoupling control of cross-polarization waves and co-polarization waves under RCP wave incidence.

[0153] The above are only specific steps of the present invention and do not constitute any limitation to the scope of protection of the present invention; any technical solutions formed by equivalent transformation or equivalent replacement fall within the scope of protection of the present invention; the parts not elaborated in detail in the present invention belong to the common knowledge of those skilled in the art.

Claims

1. A 3D printed multi-sector multifunctional metasurface, characterized in that: The 3D-printed multi-sector multifunctional metasurface includes five different azimuthal surfaces, named sectors 1 to 5, respectively. A feed source radiating non-co-polarized waves is placed in the central area surrounded by the five sectors. The first to fifth sectors have the same size, the same angle between adjacent sectors, and the same distance from the central feed source. Each azimuthal surface includes a multifunctional metasurface, and the multifunctional metasurface of each azimuthal surface includes a plurality of transmission anisotropic units, and each transmission anisotropic unit includes first to fifth metal structures, first to fourth ABS dielectric layers, and first to fifth F4B dielectric plates. The first to fourth metal structures are identical cross-shaped metal structures, and the fifth metal structure is a metal plate with circular grooves. The first to fourth metal structures are respectively disposed on the first to fourth F4B dielectric plates, and the first to fourth metal structures and the first to fourth F4B dielectric plates are separated by the first to fourth ABS dielectric layers, respectively. The fifth metal structure is arranged at the bottom of the fifth F4B dielectric plate, and the fifth metal structure and the fifth F4B dielectric plate are separated from the top-layer cascaded first to fourth metal structures by the fourth ABS dielectric layer; The width of the cross-shaped metal structure is w, and the length in the x direction of the cross-shaped metal structure is l. x , the length in the y direction is l y , by changing the structural parameter l x and l y The transmission phase can be controlled under the incidence of two orthogonal linear polarization waves; The circular groove of the metal plate with the circular groove has a radius of r and a width of g.

2. The 3D printed multi-sector multifunctional metasurface according to claim 1, characterized in that: The two orthogonal linear polarization channels in the first sector are designed with three-beam radiation and double vortex beam generation functions respectively; The second sector realizes the independent control function of two orthogonal rotational waves based on the rotational decoupling theory; The third sector realizes the vortex beam generation function with mode number l=-2 based on the PB phase; The fourth sector realizes the dual functions of co-polarization and cross-polarization decoupling under LCP wave incidence; The fifth sector realizes the decoupling and control function of the co-polarized wave and the cross-polarized wave under the incidence of the RCP wave.

3. The 3D printed multi-sector multifunctional metasurface according to claim 2, characterized in that: The azimuth planes of the first to fifth sectors respectively determine the functional phase distribution according to the function, and determine the transmission phase of the two orthogonal linear polarization waves according to the phase distribution and and the geometric phase α; And according to the transmission phase and Calculate the corresponding structural parameter l x and l y , and output the structural parameters l x and l y .

4. A method for designing a 3D printed multi-sector multifunctional metasurface according to any one of claims 1 to 3, characterized in that: The design method of the 3D printed multi-sector multifunctional metasurface comprises the following steps: Step 1, designing a transmissive anisotropic unit with high transmittance and full-cycle phase coverage; Step 2: Determine the structural parameter l in the transmission anisotropic unit x and l y ; Step 3: Design the functions of the first to fifth sectors respectively.

5. The 3D printing multi-sector multifunctional metasurface design method according to claim 4, characterized in that: Step 2 also includes the following steps: Step 21: Determine the functional phase distribution according to the specific electromagnetic function in each polarization channel, and determine the transmission phase of the two orthogonal linear polarization waves according to the phase distribution. and and the geometric phase α = 2θ, where θ represents the unit rotation angle; Step 22: traverse the transmission phase corresponding to each structural parameter in the established 2D structural unit database. and And calculate with and The error δ; Step 23: If the calculated δ meets the error requirement, output l x and l y Otherwise, and Increase the variables separately and recycle steps 22-23 to gradually approach the target value.

6. The 3D printing multi-sector multifunctional metasurface design method according to claim 4, characterized in that: Step 3 also includes the following steps: Step 31: Three-beam radiation and dual-vortex beam generation functions are designed in the two orthogonal linear polarization channels of the first sector respectively; Step 32: The second sector realizes the independent control function of two orthogonal rotational waves based on the rotational decoupling theory; Step 33, based on the PB phase, a vortex beam generation function with mode number l=-2 in the third sector metasurface is designed; Step 34, dual functions of co-polarization and cross-polarization decoupling of LCP waves in the fourth sector; Step 35: The fifth sector performs a decoupling control function on the co-polarized wave and the cross-polarized wave under the incident RCP wave.

7. The 3D printing multi-sector multifunctional metasurface design method according to claim 6, characterized in that: In step 31, the three-beam radiation phase distribution is: Where, represents the unit phase at position (m,n) in the metasurface, represents the phase distribution of the i-th beam, θ0 represents the beam pitch angle, represents the beam azimuth, ψ represents the initial phase, k0 is the free space beam, S m,n is the distance between the feed source and the unit at the (m, n)th position in the metasurface, x m,n and y m,n Represents the distance of the (m, n)th unit from the x-axis and y-axis respectively; The phase distribution of the vortex beam is: Where l = 1 represents the mode number of the vortex beam, x m,n and y m,n Represent the distances of the (m, n)th unit from the x-axis and y-axis respectively.

8. The 3D printing multi-sector multifunctional metasurface design method according to claim 6, characterized in that: In step 32, the independent control functions of the two orthogonal gyratory waves are: Under RCP wave incidence, high-gain, low-sidelobe single-beam radiation is achieved, and under LCP wave incidence, beam deflection function is realized. The phase distribution of each function, the corresponding transmission phase and geometric phase are: represents the co-polarization phase under x-polarized wave incidence, represents the co-polarization phase under the incidence of y-polarized wave, represents the functional phase of the cross-polarization channel under the incidence of right-hand circularly polarized wave, It represents the functional phase of the cross-polarization channel under the incidence of left-hand circularly polarized wave, α is the geometric phase, the geometric phase α = 2θ, and θ represents the unit rotation angle.

9. The 3D printing multi-sector multifunctional metasurface design method according to claim 6, characterized in that: In step 34, when the LCP wave is incident on the fourth sector, the transmission coefficients of the co-polarized and cross-polarized outgoing waves of the metasurface are: r RL represents the cross-polarization coefficient under left-hand circularly polarized wave incidence, r LL represents the co-polarization coefficient under left-hand circularly polarized wave incidence; the corresponding transmission phase and geometric phase are further derived as: represents the functional phase of the cross-polarization channel under left-hand circular polarization incidence, It represents the phase corresponding to the co-polarization channel function under the incidence of left-hand circularly polarized wave, represents the phase difference, represents the co-polarization phase under x-polarized wave incidence, represents the co-polarization phase under the incidence of y-polarized wave, α is the geometric phase, the geometric phase α = 2θ, and θ represents the unit rotation angle.

10. The 3D printing multi-sector multifunctional metasurface design method according to claim 6, characterized in that: In step 35, when the RCP wave is incident on the fifth sector, the transmission coefficients of the co-polarized and cross-polarized outgoing waves of the metasurface are: r LR represents the cross-polarization coefficient under right-hand circularly polarized wave incidence, r RR represents the co-polarization coefficient under right-hand circularly polarized wave incidence, and the corresponding transmission phase and geometric phase are further derived as: It represents the phase corresponding to the co-polarization channel function under the incidence of right-hand circularly polarized wave, represents the phase difference, represents the co-polarization phase under x-polarized wave incidence, represents the co-polarization phase under the incidence of y-polarized wave, α is the geometric phase, the geometric phase α = 2θ, and θ represents the unit rotation angle.

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