Phase-only electromagnetic metasurface design method based on double-phase method

Abstract

The invention discloses a phase-only electromagnetic metasurface design method based on a double-phase method. The problem that in the prior art, an electromagnetic metasurface is complex in structure when amplitude and phase are regulated and controlled at the same time is mainly solved. According to the implementation scheme, parameters of the electromagnetic metasurface are initialized; calculating a phase-only matrix required by the electromagnetic metasurface unit by using a double-phase method; designing an electromagnetic metasurface unit comprising a metal grating layer, two dielectric layers and a metal patch, and drawing a phase table of the electromagnetic metasurface unit; adjusting the state of each unit of the electromagnetic metasurface according to the phase only required by each unit of the electromagnetic metasurface and the phase table of the electromagnetic metasurface units to obtain an adjusted electromagnetic metasurface; and placing a feed source horn above the adjusted electromagnetic metasurface, and adding a radio frequency signal to the feed source horn to generate a required wave beam so as to complete the phase-only electromagnetic metasurface design. The complexity of the electromagnetic metasurface structure can be reduced, the beam design capability of the electromagnetic metasurface is improved, and the electromagnetic metasurface structure can be used for wireless transmission and communication systems.

Description

Technical Field

[0001] The present invention belongs to the technical field of electromagnetic metasurface design, and further relates to a phase-only electromagnetic metasurface design method based on a dual-phase method, which can be used in wireless transmission and communication systems. Background Art

[0002] Two-dimensional electromagnetic metasurfaces can be regarded as two-dimensional forms of metamaterials, which are composed of subwavelength units arranged periodically or non-periodically. In recent years, electromagnetic metasurfaces have been widely used in electromagnetic wave polarization, amplitude and phase control due to their powerful electromagnetic manipulation capabilities, and have become candidate materials for designing electromagnetic functional devices. Electromagnetic metasurfaces can realize beam scanning, special beam generation, etc., and are used in various scenarios such as wireless transmission and communication systems.

[0003] The patent document with application number 202311019048.2 discloses a "rotation-independent amplitude and phase coherence method and reconfigurable multifunctional device", which is designed with an electromagnetic metasurface unit with a metal structure layer, which is an active adjustable circular arc metal resonator structure, a metal floor etched with a closed circular groove, and a variable resistance diode and a switch diode feeder layer. Although this method realizes the rotation-independent amplitude and phase coherence of the electromagnetic metasurface unit. However, in order to achieve the simultaneous regulation of the amplitude and phase of the electromagnetic metasurface unit, it adds a lot of variable resistance diodes and switch diodes to the electromagnetic metasurface unit, making the structure of the electromagnetic metasurface very complex and expensive.

[0004] The patent document with application number 202211310414.5 discloses a "two-dimensional enhanced focusing Airy OAM beam phase control method", which generates an enhanced Airy OAM beam by compensating the electromagnetic metasurface phase to be the same-direction superposition of the Airy OAM phase and the near-field focusing phase. However, this method only compensates for the phase required by the Airy OAM beam and ignores the amplitude information of the Airy OAM beam, which reduces the transmission efficiency of the electromagnetic metasurface and affects the beam performance. Summary of the invention

[0005] The purpose of the present invention is to address the deficiencies of the above-mentioned prior art and propose a design method for a phase-only electromagnetic metasurface based on a dual-phase method, so as to reduce the design complexity of the electromagnetic metasurface structure, simplify the electromagnetic metasurface design process, and improve the electromagnetic metasurface beam design capability.

[0006] The idea of ​​achieving the purpose of the present invention is to convert the amplitude and phase information required by the electromagnetic metasurface into pure phase information, so that the electromagnetic metasurface only needs to design a phase-adjustable unit, and realize the ability of the electromagnetic metasurface to simultaneously control the amplitude and phase of the electromagnetic wave. By incorporating amplitude information into the calculation of the pure phase information of the electromagnetic metasurface, the near-field and far-field control of the electromagnetic metasurface have better beam control effects, thereby improving the transmission efficiency of the electromagnetic metasurface.

[0007] According to the above ideas, the technical solution of the present invention includes the following steps:

[0008] (1) Initialization:

[0009] Assume that the working wavelength of the electromagnetic metasurface is λ, and the electromagnetic metasurface is composed of M rows and N columns of units; the row spacing between units is d M , the column spacing is d N， , where N ≥ 10, M ≥ 10, d M ∈[0.3λ,0.7λ],d N ∈[0.3λ,0.7λ];

[0010] The coordinates of the feed horn are set to (0,0,f z ), where (M×d M )≤f z ≤(1.5N×d N );

[0011] The control amplitude matrix of the electromagnetic metasurface unit is set to A and the compensation phase matrix is ​​set to P, where the value range of each element of the A matrix is ​​0-1, and the value range of each element of the P matrix is ​​0-360, and the size of these two matrices is M rows and N columns;

[0012] (2) According to the control amplitude matrix A and the compensation phase matrix P of the electromagnetic metasurface unit, the phase-only matrix required by the electromagnetic metasurface unit is calculated using the dual-phase method;

[0013] (3) designing an electromagnetic metasurface unit and drawing a phase table of the electromagnetic metasurface unit;

[0014] (4) adjusting the state of each unit of the electromagnetic metasurface according to the only phase required by each unit of the electromagnetic metasurface and the phase table of the electromagnetic metasurface unit to obtain an adjusted electromagnetic metasurface;

[0015] (5) A feed horn is placed above the adjusted electromagnetic metasurface and a radio frequency signal is supplied to the feed horn to generate the desired beam, thereby completing the phase-only electromagnetic metasurface design.

[0016] Compared with the prior art, the present invention has the following beneficial effects:

[0017] First, the present invention converts the control amplitude information and compensation phase information required by the electromagnetic metasurface into phase-only information through a dual-phase method, thereby avoiding the amplitude change of the electromagnetic metasurface unit, so that the electromagnetic metasurface only needs to design phase-adjustable units, greatly reducing the complexity and cost of the electromagnetic metasurface structure and simplifying the electromagnetic metasurface design process.

[0018] Second, the present invention incorporates amplitude information into the phase compensation calculation. Compared with the traditional method of only compensating the phase required by the electromagnetic metasurface, this method can make the near-field and far-field control of the electromagnetic metasurface have better beam control effects, thereby improving the transmission efficiency of the electromagnetic metasurface. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 is a flow chart of the present invention;

[0020] Figure 2 A schematic diagram of an electromagnetic metasurface unit designed in an embodiment of the present invention;

[0021] Figure 3 A schematic diagram of a metal patch in an electromagnetic metasurface unit designed in an embodiment of the present invention;

[0022] Figure 4 A schematic diagram of compensation amplitude A and compensation phase P of an electromagnetic metasurface generating OAM modes of l=+1 and l=+2 set in the first group of parameters of the present invention;

[0023] Figure 5 is the phase-only matrix calculated in the simulation experiment 1 of the present invention Schematic diagram of

[0024] Figure 6 Schematic diagram of the electric field amplitude, electric field phase and OAM modal spectrum on the observation surface obtained by simulation experiment 2 of the present invention;

[0025] Figure 7 A schematic diagram of compensation amplitude A and compensation phase P of an electromagnetic metasurface that simultaneously generates beams with pitch angles of +40° and -40° in the second set of parameters of the present invention;

[0026] Figure 8 is the phase-only matrix calculated in simulation experiment 3 of the present invention Schematic diagram of

[0027] Fig. 9 Schematic diagram of the far-field pattern of the beam obtained in simulation experiment 4 of the present invention. DETAILED DESCRIPTION

[0028] The present invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments.

[0029] Reference Figure 1 , the implementation steps of this embodiment include the following:

[0030] Step 1: Initialization:

[0031] 1.1) Set the working wavelength of the electromagnetic metasurface, the scale of the electromagnetic metasurface, the spacing of the electromagnetic metasurface units, and the position of the feed horn:

[0032] In this example, the working wavelength of the electromagnetic metasurface is set to λ = 10 mm. The scale of the electromagnetic metasurface is composed of M rows and N columns of units, and the row spacing between the units is d M =5mm, the row spacing is d N =5mm, where N≥10, M≥10, d M ∈[0.3λ,0.7λ],d N ∈[0.3λ,0.7λ],; the coordinates of the feed horn are set to (0,0,f in the Cartesian coordinate system with the center of the electromagnetic metasurface as the origin z ), where (M×d M )≤f z ≤(1.5N×d N ), the coordinates of the center of each unit of the electromagnetic metasurface are (x m ,y n ), 1≤m≤(M+1), 1≤n≤(N+1);

[0033] 1.2) Assume the control amplitude matrix A and compensation phase matrix P required by the electromagnetic metasurface unit:

[0034] In this example, the value range of each element in the control amplitude matrix A of the electromagnetic metasurface unit is set to 0-1, and the value range of each element in the P matrix is ​​set to 0-360. The size of these two matrices is M rows and N columns.

[0035] Step 2: According to the control amplitude matrix A and compensation phase matrix P of the electromagnetic metasurface unit, the dual-phase method is used to calculate the phase-only matrix required by the electromagnetic metasurface unit

[0036] 2.1) Encode the control amplitude matrix A and the compensation phase matrix P into two pure phase matrices:

[0037] θ(m,n)=P(m,n)+arccos(A(m,n) / max(A))

[0038] ω(m,n)=P(m,n)-arccos(A(m,n) / max(A))

[0039] Among them, θ(m,n) represents the element in the mth row and nth column of the θ matrix, ω(m,n) represents the element in the mth row and nth column of the ω matrix, 1≤m≤(M+1), 1≤n≤(N+1);

[0040] 2.2) Use a two-dimensional chessboard function to encode the θ matrix and the ω matrix to obtain the two encoded matrices:

[0041]

[0042]

[0043] Among them, U1(m,n) represents the element in the mth row and nth column of the U1 matrix, and U2(m,n) represents the element in the mth row and nth column of the U2 matrix, 1≤m≤(M+1), 1≤n≤(N+1);

[0044] 2.3) According to the U1 matrix and the U2 matrix, the phase-only matrix required by the electromagnetic metasurface unit is obtained

[0045]

[0046] in, represents the required unique phase of the m-th row and n-th column unit in the electromagnetic metasurface, 1≤m≤(M+1), 1≤n≤(N+1).

[0047] Step 3: Design the electromagnetic metasurface unit and draw a phase table of the electromagnetic metasurface unit.

[0048] 3.1) Design electromagnetic metasurface unit;

[0049] Reference Figure 2 The electromagnetic metasurface unit designed in this example includes two metal grating layers, two dielectric layers and a metal patch, and its structure is: the first metal grating layer, the first dielectric layer, the metal patch, the second dielectric layer, and the second metal grating layer are linked in sequence;

[0050] The two dielectric layers are cuboids of equal volume and shape. In this example, a cuboid of 5 mm in length, 5 mm in width and 2 mm in height is selected but not limited to F4B plate with a relative dielectric constant of 2.2 and a loss tangent of 0.0015;

[0051] The first metal grating is composed of three square metal sheets of the same size and equal spacing arranged in parallel along the x-axis direction of the substrate, and the spacing between two metal sheets is 1 mm;

[0052] The second metal grating is composed of three square metal sheets of the same size and equal spacing arranged in parallel along the y-axis direction of the substrate, and the spacing between two metal sheets is 1 mm; the two metal grating layers are printed on the upper and lower ends of the first dielectric layer and the second dielectric layer respectively;

[0053] The metal patch is printed between the first dielectric layer and the second dielectric layer, and its shape is an I-shaped patch with an opening size of α and an angle of 45° between the central axis and the x-axis, such as Figure 3 As shown, the opening angle of the metal patch is used to control the transmission phase of the electromagnetic metasurface unit, and the value range of α is [7°, 105°];

[0054] 3.2) Draw the phase table of the electromagnetic metasurface unit;

[0055] By changing the opening angle α of the metal patch through simulation, the transmission phase corresponding to each value of the opening angle α of the metal patch is obtained, and each value of the opening angle α of the metal patch and the corresponding transmission phase are plotted into a phase table.

[0056] In this example, when the opening angle α of the metal patch changes from 7° to 105°, the transmission phase of the electromagnetic metasurface unit changes linearly from 136° to 334°. When the metal patch rotates 90° around the z-axis, the transmission phase of the unit changes linearly from -44° to 158°. A phase table of the opening angle α of the metal patch and its corresponding transmission phase is obtained.

[0057] Step 4: adjust the state of each unit of the electromagnetic metasurface according to the only phase required by each unit of the electromagnetic metasurface and the phase table of the electromagnetic metasurface unit to obtain an adjusted electromagnetic metasurface.

[0058] In this example, adjusting the state of each unit of the electromagnetic metasurface refers to changing the opening angle α of the electromagnetic metasurface unit, by looking up the metal patch opening angle α corresponding to the only phase required by each unit of the electromagnetic metasurface in the phase table of the electromagnetic metasurface unit, and adjusting the opening angle α of the metal patch of each unit of the electromagnetic metasurface accordingly, and the value range of α is [7°, 105°];

[0059] The adjusted electromagnetic metasurface unit center is adjusted according to its rectangular coordinate system position (x m ,y n ) are placed to obtain an electromagnetic metasurface with an adjusted scale of M×N, 1≤m≤(M+1), 1≤n≤(N+1).

[0060] Step 5: Place a feed horn above the adjusted electromagnetic metasurface and add a radio frequency signal to the feed horn to generate the required beam, thereby completing the phase-only electromagnetic metasurface design.

[0061] In this example, a spatial coordinate system is constructed with the center of the electromagnetic metasurface as the origin, and the feed horn is placed at (0,0,f z ) and add an RF signal to the feed horn to generate the desired beam.

[0062] The technical effects of the present invention are further described below in combination with simulation experiments and sampling result analysis.

[0063] 1. Simulation experiment conditions:

[0064] The hardware platform of the simulation experiment of the present invention is: the processor is Intel(R) Core(TM) i7-10700 CPU, the main frequency is 2.90GHz, and the memory is 16GB.

[0065] The software platforms for the simulation experiment of the present invention are: Windows 10 operating system, Ansys HFSS2021 and MATLAB R2020b.

[0066] The data of the simulation experiment of the present invention is set to two groups, where:

[0067] The first set of parameters is set as follows: the beam generated by the electromagnetic metasurface is set to be a vortex beam with multiple OAM modes of -1 and -2, the electromagnetic metasurface is set to be located in the xoy plane of the Cartesian coordinate system, the electromagnetic metasurface operating frequency f = 30GHz, and the operating wavelength λ = 10mm. The electromagnetic metasurface is composed of 20 rows and 20 columns of units, the row spacing between each unit is 5mm, the column spacing between each unit is 5mm, and the coordinates of the feed horn in the Cartesian coordinate system are set to (0, 0, 120mm). By setting the electric field distribution of the beam, the control amplitude matrix of the electromagnetic metasurface unit can be obtained as A, such as Figure 4 As shown in (a), the horizontal axis represents the position coordinate of the unit in the x direction, and the vertical axis represents the position coordinate of the unit in the y direction, and the amplitude is distributed between 0 and 1. The electromagnetic metasurface unit compensation phase matrix required for this beam is P, as shown in Figure 4 (b), where the horizontal axis represents the position coordinate of the unit in the x direction, the vertical axis represents the position coordinate of the unit in the y direction, and the phase distribution is between 0° and 360°.

[0068] The second set of parameters is set as follows: Set the electromagnetic metasurface to generate a beam with a pitch angle of +40° and -40°, and an azimuth angle of 0°. Set the electromagnetic metasurface to be located in the xoy plane of the Cartesian coordinate system. The electromagnetic metasurface operating frequency f = 30GHz, and the operating wavelength λ = 10mm. The electromagnetic metasurface is composed of 40 rows and 40 columns of units. The row spacing between each unit is 5mm, and the column spacing between each unit is 5mm. The coordinates of the feed horn in the Cartesian coordinate system are set to (0, 0, 150mm). Set the control amplitude matrix of the electromagnetic metasurface unit required for the beam to A, such as Figure 7 As shown in (a), the horizontal axis represents the position coordinate of the unit in the x direction, and the vertical axis represents the position coordinate of the unit in the y direction, and the amplitude is distributed between 0 and 1. The electromagnetic metasurface unit compensation phase matrix required for this beam is P, as shown in Figure 7 (b), where the horizontal axis represents the position coordinate of the unit in the x direction, the vertical axis represents the position coordinate of the unit in the y direction, and the phase distribution is between 0° and 360°.

[0069] 2. Simulation content and results analysis:

[0070] Simulation experiment 1: Under the above first set of parameter conditions, the method of the present invention is used through the simulation software MATLABR2020b to calculate the phase-only matrix required by the electromagnetic metasurface unit according to the set control amplitude matrix A and compensation phase matrix P. like Figure 5 As shown, the horizontal axis represents the position coordinate of the unit in the x direction, the vertical axis represents the position coordinate of the unit in the y direction, and the phase distribution is between 0° and 360°.

[0071] from Figure 5 It can be seen that the present invention Figure 4 (a) The control amplitude matrix A and Figure 4 The compensation phase matrix P of (b) can obtain the only phase matrix required by the electromagnetic metasurface unit. According to the phase-only matrix Electromagnetic metasurfaces can be designed.

[0072] In simulation experiment 2, after obtaining the designed electromagnetic metasurface under the above first set of parameter conditions, the feed horn is RF excited by the simulation software Ansys HFSS2021, and a 200mm×200mm observation surface is added at (0,0,-200m). The electric field distribution and OAM mode distribution of the beam on the observation surface are simulated, as shown in Figure 2. Figure 6 As shown. Among them:

[0073] Figure 6 (a) is the electric field amplitude distribution, and the side axis represents the magnitude of the electric field amplitude;

[0074] Figure 6 (b) is the electric field phase distribution, and the side axis represents the phase value of the electric field;

[0075] Figure 6 (c) is the OAM modal spectrum distribution, the horizontal axis represents the OAM modal value, and the vertical axis represents the modal purity of OAM.

[0076] from Figure 6 It can be seen that the electromagnetic metasurface designed in the present invention successfully generates OAM mode -1, OAM mode -2 and multiple OAM mode vortex beams, and the generated beams are in the shape of a hollow ring, and the near-field beam effect is good.

[0077] Simulation experiment 3, under the above second set of parameter conditions, the method of the present invention is used through the simulation software MATLABR2020b to calculate the phase-only matrix required by the electromagnetic metasurface unit according to the set control amplitude matrix A and compensation phase matrix P like Figure 8 As shown, the horizontal axis represents the position coordinate of the unit in the x direction, the vertical axis represents the position coordinate of the unit in the y direction, and the phase distribution is between 0° and 360°.

[0078] from Figure 8 It can be seen that the present invention Figure 7 (a) The control amplitude matrix A and Figure 7 The compensation phase matrix P of (b) can obtain the only phase matrix required by the electromagnetic metasurface unit. According to the phase-only matrix Electromagnetic metasurfaces can be designed.

[0079] In simulation experiment 4, after obtaining the designed electromagnetic metasurface under the above second set of parameter conditions, the feed horn is subjected to RF excitation through the simulation software Ansys HFSS2021, and the far-field pattern when the azimuth angle is 0° is simulated, as shown in Fig. 9 As shown, the ordinate represents the gain of the beam, the abscissa represents the elevation angle of the far field, and the elevation angle is between -180° and +180°.

[0080] from Fig. 9 It can be seen that the electromagnetic metasurface designed in the present invention successfully generates beams with pitch angles of +40° and -40°, and the gains of the two beams are 23dB, and the difference between the sidelobe gain and the main beam gain is 15dB, achieving excellent far-field beam performance.

[0081] The above simulation results show that the electromagnetic metasurface designed by the present invention can realize the generation of near-field beams and far-field beams.

[0082] The above description is only a specific example of the present invention and does not constitute any limitation to the present invention. It is obvious that for professionals in this field, after understanding the content and principles of the present invention, it is possible to make various modifications and changes in form and details without departing from the principles and structures of the present invention. However, these modifications and changes based on the ideas of the present invention are still within the scope of protection of the claims of the present invention.

[0083] It should be noted that the step numbers in the specification and claims of the present invention are only for a clear description of the implementation scheme of the present invention to facilitate understanding, and the order of the step numbers is not limited.

Claims

1. A phase-only electromagnetic metasurface design method based on a dual-phase method, characterized in that: The steps include: (1) Initialization: Assume that the working wavelength of the electromagnetic metasurface is λ, and the electromagnetic metasurface is composed of M rows and N columns of units; the row spacing between units is d M , the column spacing is d N , where N ≥ 10, M ≥ 10, d M ∈[0.3λ,0.7λ],d N ∈[0.3λ,0.7λ]; The coordinates of the feed horn are set to (0,0,f z ), where (M×d M )≤f z ≤(1.5N×d N ); The control amplitude matrix of the electromagnetic metasurface unit is set to A and the compensation phase matrix is ​​set to P, where the value range of each element of the A matrix is ​​0-1, and the value range of each element of the P matrix is ​​0-360, and the size of these two matrices is M rows and N columns; (2) According to the control amplitude matrix A and the compensation phase matrix P of the electromagnetic metasurface unit, the phase-only matrix required by the electromagnetic metasurface unit is calculated using the dual-phase method; (3) Designing an electromagnetic metasurface unit including a metal grating layer, a dielectric layer and a metal patch, and drawing a phase table of the electromagnetic metasurface unit; (4) adjusting the state of each unit of the electromagnetic metasurface according to the only phase required by each unit of the electromagnetic metasurface and the phase table of the electromagnetic metasurface unit to obtain an adjusted electromagnetic metasurface; (5) A feed horn is placed above the adjusted electromagnetic metasurface and a radio frequency signal is supplied to the feed horn to generate the desired beam, thereby completing the phase-only electromagnetic metasurface design.

2. The method according to claim 1, characterized in that: The control amplitude matrix A of the electromagnetic metasurface unit set in step (1) is expressed as follows: A(m,n)=mag(E(x m ,y n )) Among them, A(m,n) represents the element in the mth row and nth column of the A matrix, E(x m ,y n ) represents the electromagnetic metasurface at (x m ,y m ) required electric field distribution, (x m ,y n ) indicates that the coordinates of the center of the mth row and nth column unit of the electromagnetic metasurface in the plane coordinate system are (x m ,y n ), 1≤m≤(M+1), 1≤n≤(N+1).

3. The method according to claim 1, characterized in that: The compensation phase matrix P set in step (1) is expressed as follows: P=arg(E(x m ,y n )) Wherein, P(m,n) represents the element in the m-th row and n-th column of the P matrix, 1≤m≤(M+1), 1≤n≤(N+1).

4. The method according to claim 1, characterized in that In step (2), the dual-phase method is used to calculate the phase-only matrix required by the electromagnetic metasurface unit, and the implementation steps include the following: 2a) Encode the control amplitude matrix A and the compensation phase matrix P into two pure phase matrices: θ(m,n)=P(m,n)+arccos(A(m,n) / max(A)) ω(m,n)=P(m,n)-arccos(A(m,n) / max(A)) Wherein, θ(m,n) represents the element in the mth row and nth column of the θ matrix, ω(m,n) represents the element in the mth row and nth column of the ω matrix, 1≤m≤(M+1), 1≤n≤(N+1); 2b) Encode the θ matrix and the ω matrix using a two-dimensional chessboard function to obtain two encoded matrices: Among them, U1(m,n) represents the element in the mth row and nth column of the U1 matrix, and U2(m,n) represents the element in the mth row and nth column of the U2 matrix, 1≤m≤(M+1), 1≤n≤(N+1); 2c) According to the U1 matrix and the U2 matrix, the phase-only matrix required by the electromagnetic metasurface unit is obtained in, represents the required unique phase of the m-th row and n-th column unit in the electromagnetic metasurface, 1≤m≤(M+1), 1≤n≤(N+1).

5. The method according to claim 1, characterized in that The electromagnetic metasurface unit designed in step (3) comprises two metal grating layers, two dielectric layers and a metal patch, and its structure is: a first metal grating layer, a second metal grating layer, a metal patch, a first dielectric layer and a second dielectric layer; The two dielectric layers are cuboids of equal volume and same shape; The first metal grating is composed of three square metal sheets of the same size and equal spacing arranged in parallel along the x-axis direction of the substrate; the second metal grating is composed of three square metal sheets of the same size and equal spacing arranged in parallel along the y-axis direction of the substrate; the two metal grating layers are printed on the upper and lower ends of the first and second dielectric layers respectively; The metal patch is printed between the first dielectric layer and the second dielectric layer, and its shape is any one of an open ring type and an I type. The opening angle of the metal patch is used to control the transmission phase of the electromagnetic metasurface unit.

6. The method according to claim 1, characterized in that Step (3) draws the phase table of the designed electromagnetic metasurface unit by simulating the change of the opening angle of the metal patch to obtain the transmission phase corresponding to each value of the opening angle of the metal patch, and draws each value of the opening angle of the metal patch and the corresponding transmission phase into a phase table.

7. The method according to claim 1, characterized in that In step (4), the state of each unit of the electromagnetic metasurface is adjusted according to the unique phase required by each unit of the electromagnetic metasurface and the phase table of the electromagnetic metasurface unit. The metal patch opening angle corresponding to the unique phase of each unit of the electromagnetic metasurface is found from the phase table, and the opening angle of the metal patch of each unit of the electromagnetic metasurface is adjusted accordingly.

8. The method according to claim 1, characterized in that Placing the feed horn above the adjusted electromagnetic metasurface in step (5) means constructing a spatial coordinate system with the center of the electromagnetic metasurface as the origin, and placing the feed horn at (0,0,f z ) place.

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