Integrated three-beam look-back array and its design method

Abstract

The present application discloses an integrated three-beam tracing array and a design method thereof, wherein the tracing array is composed of a periodic extension of a number of non-uniform metasurface units; each metasurface unit comprises two layers of composite metal structure and a bottom metal back plate, and the three layers of metal structure are separated by two layers of dielectric plates with a height of h; the composite metal structures are composed of an outer cross ring and an inner cross patch, and the cross ring is nested in the cross patch; the structural parameters of each non-uniform metasurface unit are determined by a hybrid geometric phase and transmission phase method; in addition to realizing three-beam tracing, the integrated three-beam tracing array can also realize four additional reflected beams with different angles in other rotational channels under three different incident angles, including the tracing beam to form a total of seven outgoing beams with different angles, and has the advantages of high integration, large channel capacity and easy processing of planar structure.

Description

Technical Field

[0001] The present application relates to the technical field of metasurface electromagnetic control, and in particular to an integrated three-beam tracing array and a design method of the integrated three-beam tracing array. Background Art

[0002] Beam tracers are important devices in the fields of navigation safety, target identification, RCS / visibility enhancement, remote sensing and satellite communications because they can return the outgoing electromagnetic waves along their inclined incident direction. Currently, conventional beam tracers, such as corner reflectors and Lumper lenses, cannot meet the requirements of integration and miniaturization due to their large size, heavy weight and non-planar layout, which hinders their practical application and promotion.

[0003] In the prior art, metasurface structures are usually used to realize integrated beam tracers, especially adaptive beam tracers. For example, by changing the geometric shape of the reconfigurable C-shaped resonator or the switchable grating through a mechanical structure, the functional characteristics of the beam tracer can be dynamically controlled. However, such beam tracers are all based on active metasurfaces, but for passive metasurfaces, especially those covering the entire space with large angles, it is still extremely challenging, especially for composite integrated large-capacity tracers, which have important potential applications in multi-target tracking. Summary of the invention

[0004] The purpose of this application is to propose a deterministic integrated three-beam retracement method based on metasurface hybrid geometric phase and transmission phase, and to realize multiple retracement beams on a single board. The core mechanism is to combine the geometric phase and transmission phase to achieve three completely decoupled chirality channels, and synthesize different phase distributions with different retracement angles in the three chirality channels.

[0005] The technical solution of the first aspect of the present application is: an integrated three-beam tracing array is provided, which is composed of multiple metasurface units. The metasurface unit includes two layers of composite metal structures with the same structure and a bottom metal backplane arranged in sequence. The composite metal structure includes: a cross ring and a cross patch; the cross patch is nested in the inside of the cross ring, the center line of the cross patch coincides with the center line of the cross ring, and the cross patch and the cross ring are tilted according to the unit rotation angle, wherein the metasurface unit is periodically repeated along the y direction, so that when the electromagnetic wave is incident on the integrated three-beam tracing array at three different angles, the reflected beam of the electromagnetic wave is emitted at the same angle as the incident angle, realizing the three-tracing beam function, and the three-tracing beam function occurs in different rotation channels, respectively, which are recorded as right-handed ← left-handed channel, left-handed ← right-handed channel and right-handed ← right-handed channel, or right-handed ← left-handed channel, left-handed ← right-handed channel and left-handed ← left-handed channel.

[0006] In any of the above technical solutions, further, the three different incident angles of the electromagnetic wave include a given first incident angle θ i1 and the second incident angle θ i2 , integrating the electromagnetic wave emission angle in each rotation channel of the three-beam tracing array and the third incident angle θ i3 Determined by the law of conservation of momentum, the corresponding calculation formula is:

[0007] 2kd sinθ i1 =ξ RL =ξ 0 +2ψ

[0008] 2kd sinθ i2 =ξ LR =ξ 0 -2ψ

[0009] 2kd sinθ i3 =ξ LL =ξ RR =ξ 0

[0010] kd(sinθ i1 +sinθ r1a )=ξ LR =ξ 0 -2ψ

[0011] kd(sinθ i1 +sinθ r1b )=ξ LL =ξ RR =ξ 0

[0012] kd(sinθ i1 +sinθ r1c )=ξ RL =ξ 0 +2ψ

[0013] kd(sinθ i2 +sinθ r2a )=ξ LR =ξ 0 -2ψ

[0014] kd(sinθ i2 +sinθ r2b )=ξ LL =ξ RR =ξ 0

[0015] kd(sinθ i2 +sinθ r2c )=ξ RL =ξ 0 +2ψ

[0016] kd(sinθ i3 +sinθ r3a )=ξ LR =ξ 0 -2ψ

[0017] kd(sinθ i3 +sinθ r3b )=ξ LL =ξ RR =ξ 0

[0018] kd(sinθ i3 +sinθ r3c )=ξ RL =ξ 0 +2ψ

[0019] Where k is the wave vector in free space, d is the metasurface unit period, Ψ is the unit rotation angle, ξ RL , LR , LL and RR are the functional phase distributions on the right-handed ← left-handed channel, the left-handed ← right-handed channel, the left-handed ← left-handed channel, and the right-handed ← right-handed channel, ξ 0 is the transmission phase when the unit is not rotated, θ ria ,θ rib ,θ ric The exit angles corresponding to the three different angles of incidence are shown in Table 1. The subscripts a, b, and c represent different rotation channels, respectively. a represents a left-handed ← right-handed channel, b represents a left-handed ← left-handed channel or a right-handed ← right-handed channel, and c represents a right-handed ← left-handed channel. i = 1, 2, and 3 correspond to the first incident angle θ. i1 , the second incident angle θ i2 and the third incident angle θ i3 situation.

[0020] In any of the above technical solutions, further, the calculation formula of the electromagnetic wave emission angle in the integrated three-beam tracing array is:

[0021] θ r1c =θ r2b =θ i1

[0022] θ r2a =θ r1b =θ i2

[0023] θ r3b =θ i3

[0024] θ r1a=arcsin(2sinθ i2 -sinθ i1 )

[0025] θ r2c =arcsin(2sinθ i1 -sinθ i2 )

[0026]

[0027]

[0028]

[0029] In the formula, θ ria ,θ rib ,θ ric The exit angles corresponding to the three different angles of incidence are shown in Table 1. The subscripts a, b, and c represent different rotation channels, respectively. a represents a left-handed ← right-handed channel, b represents a left-handed ← left-handed channel or a right-handed ← right-handed channel, and c represents a right-handed ← left-handed channel. i = 1, 2, and 3 correspond to the first incident angle θ. i1 , the second incident angle θ i2 and the third incident angle θ i3 situation.

[0030] In any of the above technical solutions, further, the two-layer composite metal structure is sequentially recorded as a first composite metal structure and a second composite metal structure, a first dielectric plate is arranged between the first composite metal structure and the second composite metal structure, and a second dielectric plate is arranged between the second composite metal structure and the bottom metal back plate, wherein the thickness of the first dielectric plate and the second dielectric plate are the same.

[0031] In any of the above technical solutions, further, the cross patch includes an x-direction cross patch and a y-direction cross patch, and the structural parameters of the metasurface unit at least include the length l of the x-direction cross patch x and the length l of the cross patch in the y direction y The structural parameters of the metasurface unit are determined by a hybrid geometric phase and transmission phase design method, which specifically includes: step A, within a preset variation range, parameter scanning is performed according to a preset step size to establish the length l of the cross patch in the x direction under the excitation of the x-polarized wave and the y-polarized wave respectively. x and the length l of the cross patch in the y direction y The two-dimensional scanning phase matrix of the change is recorded as matrix PhaseX(l x ,l y ) and the matrix PhaseY(l x ,l y); Step B, according to the given two cross-rotation channels, the retracement beam angle θ i1 and θ i2 And the number of metasurface units Nx*Ny, calculate the functional phase distribution ξ RL and LR Step C, using the rotational decoupling method, according to the functional phase distribution ξ RL and LR , calculate the linear co-polarization phase distribution of each metasurface unit at the position in the integrated three-beam traceback array under x-polarization wave and y-polarization wave and and the geometric phase distribution 2Φ; Step D, using the minimum Euclidean distance algorithm to calculate the linear co-polarization phase distribution and With the matrix PhaseX(l x ,l y ) and the matrix PhaseY(l x ,l y ) and select the data corresponding to the minimum Euclidean distance δ as the length l of the cross patch in the x direction x and the length l of the cross patch in the y direction y , where the geometric phase distribution 2Φ is equal to twice the unit rotation angle Ψ.

[0032] In any of the above technical solutions, further, the structural parameters of the super surface unit include at least: the period p of the super surface unit along the x direction x , the period of the hypertable unit along the y direction is p y , period p x and period p y All of them are less than the central operating frequency f of the integrated three-beam retracement array 0 The working wavelength λ 0 .

[0033] In any of the above technical solutions, further, the period p of the hypertable unit along the x direction is x Equal to the period p of the hypertable unit along the y direction y , the period of the hypertable unit along the x direction is p x Smaller than the working wavelength λ 0 1 / 3 of the total length; the structural parameters of the super surface unit also include: the length r of the cross ring along the x and y directions x and r y , r x =r y =9mm, width d of the cross ring 1 , d 1 =0.5mm, the gap distance d between the cross ring and the cross patch 2 , d 2=0.5mm, the width w of the cross patch, w=1mm.

[0034] The technical solution of the second aspect of the present application is: a design method for an integrated three-beam tracing array is provided, and the design method includes: step 1, determining the structure and structural parameters of the integrated three-beam tracing array, wherein the structure of the integrated three-beam tracing array includes a plurality of metasurface units, and the metasurface units are provided with nested cross rings and cross patches, and the cross patches include x-direction cross patches and y-direction cross patches, and the structural parameters include the number of metasurface units Nx*Ny; step 2, within a preset variation range, performing parameter scanning according to a preset step size, and establishing the length l of the x-direction cross patch under the excitation of the x-polarized wave and the y-polarized wave respectively. x and the length l of the cross patch in the y direction y The two-dimensional scanning phase matrix of the change is recorded as matrix PhaseX(l x ,l y ) and the matrix PhaseY(l x ,l y ); Step 3, according to the given two cross-rotation channels, the backtracking beam angle θ i1 and θ i2 And the number of metasurface units Nx*Ny, calculate the functional phase distribution ξ RL and LR ; Step 4, using the rotational decoupling method, according to the functional phase distribution ξ RL and LR , calculate the linear co-polarization phase distribution of the metasurface unit at each position in the integrated three-beam traceback array under x-polarized waves and y-polarized waves and And the geometric phase distribution 2Φ; Step 5, using the minimum Euclidean distance algorithm, calculate the linear co-polarization phase distribution and With the matrix PhaseX(l x ,l y ) and the matrix PhaseY(l x ,l y ) and select the data corresponding to the minimum Euclidean distance δ as the length l of the cross patch in the x direction x and the length l of the cross patch in the y direction y ; Step 6, according to the length l of the cross patch in the x direction x and the length l of the cross patch in the y direction y The size of the cross patch is determined, and the unit rotation angle of the cross patch is determined according to the geometric phase distribution 2Φ to form an integrated three-beam traceback array.

[0035] In any of the above technical solutions, further, step 5 also includes: x and length l y The actual phase and ideal phase corresponding to the excitation of x and y polarized waves and Make a difference and find the error When the judgment error Less than the threshold δ 0 When the length l x and length l y As the length l of the final x-direction cross patch of the metasurface unit x and the length l of the cross patch in the y direction y , then execute step 6; when the error is determined Greater than or equal to the threshold δ 0 When the phase distribution of the linear co-polarization and Add a micro variable and repeat step 5.

[0036] In any of the above technical solutions, further, step 2 also includes: adjusting the lengths l of two adjacent x-direction cross patches selected within a preset range according to a preset step length. x and the length l of the cross patch in the y direction y Perform two-dimensional interpolation.

[0037] In any of the above technical solutions, further, the linear co-polarization phase distribution and And the calculation formula of geometric phase distribution 2Φ is:

[0038]

[0039]

[0040]

[0041]

[0042] In the formula, is the first parameter, is the second parameter.

[0043] In any of the above technical solutions, further, the structural parameters of the super surface unit include at least: the period p of the super surface unit along the x direction x , the period of the hypertable unit along the y direction is p y , period p x and period p y All of them are less than the central operating frequency f of the integrated three-beam retracement array 0The working wavelength λ 0 .

[0044] In any of the above technical solutions, further, the period p of the hypertable unit along the x direction is x Equal to the period p of the hypertable unit along the y direction y , the period of the hypertable unit along the x direction is p x Smaller than the working wavelength λ 0 1 / 3 of the total length; the structural parameters of the super surface unit also include: the length r of the cross ring along the x and y directions x and r y , r x =r y =9mm, width d of the cross ring 1 , d 1 =0.5mm, the gap distance d between the cross ring and the cross patch 2 , d 2 =0.5mm, the width w of the cross patch, w=1mm.

[0045] The beneficial effects of this application are:

[0046] The technical solution in this application realizes an integrated three-beam tracing array, realizes three completely decoupled directional channels, and synthesizes different phase distributions with different tracing angles in the three directional channels. And the integrated three-beam tracing array has the following advantages:

[0047] 1. No need to introduce active devices and power supply bias circuits, low cost, simple structure and easy processing;

[0048] 2. It can integrate remote weak signal enhanced detection and bait deception stealth functions, and has important potential applications;

[0049] 3. The scattered beam of each chirality channel has only a singular scattering mode, with high mode purity and efficiency;

[0050] 4. It can form three traceback beams and four scattered beams at different angles by simply switching the excitation signal angle and the rotation direction of the circular polarization detector.

[0051] In the integrated three-beam tracing array and its design method of the present application, the geometric phase and the transmission phase are combined. When the linearly polarized wave is transmitted at three different angles θ i1 ,θ i2 and θ i3 When incident on the tracing array, three scattered beams pointing at different angles will be formed respectively, including one tracing beam returning along the original direction of the incident direction and two scattered beams at other angles, and two of the nine beams have the same pointing angle. Therefore, the integrated tracing array can form seven outgoing beams at different angles in space, with the advantages of high integration, large channel capacity and easy processing of planar structure. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] The advantages of the above and / or additional aspects of the present application will become apparent and easily understood in the description of the embodiments in conjunction with the following drawings, in which:

[0053] Figure 1 A functional schematic diagram of an integrated three-beam traceback array according to an embodiment of the present application;

[0054] Figure 2 A schematic diagram of an integrated three-beam traceback array according to an embodiment of the present application;

[0055] FIG3( a ) is a structural diagram of a metasurface unit according to an embodiment of the present application;

[0056] FIG3( b ) is a schematic diagram of parameters of a metasurface unit according to an embodiment of the present application;

[0057] Figure 4 A schematic flow chart of a design method of an integrated three-beam traceback array according to an embodiment of the present application;

[0058] Figure 5 The collinear polarization phase and rotation angle diagram required for the inversion calculation of the integrated three-beam traceback array of one embodiment of the present application;

[0059] Figure 6 A schematic diagram of two-dimensional colinear polarization reflection amplitude scanning data of an integrated three-beam traceback array metasurface unit in one embodiment of the present application;

[0060] Figure 7 A schematic diagram of two-dimensional colinear polarization reflection phase scanning data of an integrated three-beam traceback array metasurface unit in one embodiment of the present application;

[0061] Figure 8 A one-dimensional colinear polarization phase error diagram between the actual implementation and the ideal calculated phase of an integrated three-beam traceback array according to an embodiment of the present application.

[0062] Fig. 9 An integrated three-beam traceback array of one embodiment of the application x and l y Value distribution graph.

[0063] Fig.10 A three-dimensional scattering pattern is simulated for an integrated three-beam traceback array of one embodiment of the application.

[0064] Fig.11 An integrated three-beam traceback array xoz of one embodiment of the application simulates a two-dimensional scattering pattern in the main plane. DETAILED DESCRIPTION

[0065] In order to more clearly understand the above-mentioned purposes, features and advantages of the present application, the present application is further described in detail below in conjunction with the accompanying drawings and specific implementation methods. It should be noted that the embodiments of the present application and the features in the embodiments can be combined with each other without conflict.

[0066] In the following description, many specific details are elaborated to facilitate a full understanding of the present application. However, the present application may also be implemented in other ways different from those described herein. Therefore, the protection scope of the present application is not limited to the specific embodiments disclosed below.

[0067] To facilitate understanding by those skilled in the art, the symbol ← is used in this embodiment to represent conversion.

[0068] like Figure 1 As shown, the integrated three-beam traceback array can achieve three functions: function F 1 、F 2 and F 3 Occurs at three different angles θ i1 ,θ i2 and θ i3 On, that is, the electromagnetic wave is on θ i1 ,θ i2 and θ i3 Angle of incidence, the reflected beam will be emitted along the original direction, and the function of the three-beam tracing array is integrated. 1 , F 2 and F 3 It occurs in channels with different rotation directions, namely right-handed←left-handed, left-handed←right-handed and right-handed←right-handed (left-handed←left-handed).

[0069] Integrated three-beam backtracking array function F 1 、F 2 and F 3 In addition to the backtracking beam, the remaining rotational channels also include two reflected beams at other angles, forming a total of 7 outgoing beams at different angles, including the backtracking beam.

[0070] For the function F 1 , the electromagnetic wave travels along θ i1 Direction of incidence, in the right-handed←left-handed channel, along θ i1 =θ r1c The retracement beam returning along the original path is along θ in the right-handed ← right-handed or left-handed ← left-handed channel. r1b The reflected outgoing beam is along θ in the left-handed←right-handed channel. r1a The reflected outgoing beam;

[0071] For the function F 2 , the electromagnetic wave travels along θ i2 Direction of incidence, in the left-handed←right-handed channel, along θi2 =θ r2a The retracement beam returning along the original path is along θ in the right-handed ← right-handed or left-handed ← left-handed channel. r2b The reflected outgoing beam is along θ in the right-handed←left-handed channel. r2c The reflected outgoing beam;

[0072] For the function F 3 , the electromagnetic wave travels along θ i3 Direction of incidence, in the right-handed ← right-handed or left-handed ← left-handed channel, along θ i3 =θ r3b The tracing beam returning along the original path is along θ in the left-handed←right-handed channel. r3a The reflected outgoing beam is along θ in the right-handed←left-handed channel. r3c Reflected outgoing beam.

[0073] Embodiment 1:

[0074] The present embodiment provides an integrated three-beam tracing array, which is composed of a plurality of metasurface units, which are repeatedly arranged in the y-axis direction, and the metasurface units include: two layers of composite metal structures arranged up and down and a layer of bottom metal backplane, wherein the two layers of composite metal structures have the same structure, and the composite metal structure includes a cross ring and a cross patch, and the cross patch is arranged inside the cross ring, and the center line of the cross patch coincides with the center line of the cross ring, and the cross ring is tilted according to the unit rotation angle, so that when the electromagnetic wave is incident on the integrated three-beam tracing array at three different angles, the reflected beam of the electromagnetic wave is emitted at the same angle as the incident angle, thereby realizing the three-tracing beam function, that is, the above-mentioned function F 1 、F 2 and F 3 , and the three traceback beam functions occur in different rotational channels, which are recorded as right-handed ← left-handed channel, left-handed ← right-handed channel and right-handed ← right-handed channel, or right-handed ← left-handed channel, left-handed ← right-handed channel and left-handed ← left-handed channel.

[0075] In this embodiment, the unit rotation angle is determined by the tracing angle (incident angle) of a given tracing beam on two cross circular polarization channels. The calculation formula of the unit rotation angle ψ is:

[0076]

[0077] Where k is the wave vector in free space, d is the metasurface unit period, and θ i1 is the first given electromagnetic wave incident angle, ψ is the unit rotation angle, θ i2 is the second given electromagnetic wave incident angle.

[0078] The cross patch includes an x-direction cross patch and a y-direction cross patch, wherein the length of the x-direction cross patch is l x and the length l of the cross patch in the y direction y Determined by the phase of the metasurface unit along the x-axis;

[0079] The bottom metal back plate is arranged below the two-layer composite metal structure.

[0080] That is to say, the metasurface units constituting the integrated three-beam traceback array in this embodiment are only along one dimension, such as along the x direction, and the length of the cross patch in the x direction is l x , y-direction cross patch length l y The unit rotation angle ψ parameter is constantly changing, while the periodic repetition is maintained along another orthogonal dimension, such as along the y direction. By adjusting the length l x , l y and the unit rotation angle ψ, the integrated three-beam back-tracing array composed of the above-mentioned multiple metasurface units can achieve the expected function.

[0081] Embodiment 2:

[0082] On the basis of the above embodiments, this embodiment provides an integrated three-beam tracing array, which is composed of multiple metasurface units. The metasurface unit includes two layers of composite metal structures with the same structure and a bottom metal backplane arranged in sequence. The composite metal structure includes: a cross ring and a cross patch; the cross patch is nested inside the cross ring, and the center line of the cross patch coincides with the center line of the cross ring. The cross ring is tilted according to the unit rotation angle. The cross patch includes an x-direction cross patch and a y-direction cross patch. The metasurface unit is periodically repeated along the y direction so that when the electromagnetic wave is incident on the integrated three-beam tracing array at three different angles, the reflected beam of the electromagnetic wave is emitted at the same angle as the incident angle, realizing the three-tracing beam function, and the three-tracing beam function occurs in different rotation channels, which are respectively recorded as right-handed ← left-handed channel, left-handed ← right-handed channel and right-handed ← right-handed channel, or right-handed ← left-handed channel, left-handed ← right-handed channel and left-handed ← left-handed channel.

[0083] Specifically, a rectangular coordinate system is established, such as Figure 2 As shown in FIG3 , the metasurface units constituting the integrated three-beam traceback array in this embodiment are only along one dimension, such as along the x direction, and the length of the cross patch in the x direction is l x , y-direction cross patch length l y The unit rotation angle ψ parameter is constantly changing, while the periodic repetition is maintained along another orthogonal dimension, such as along the y direction. By adjusting the length l x , l yand the unit rotation angle ψ, the integrated three-beam back-tracing array composed of the above-mentioned multiple metasurface units can achieve the expected function.

[0084] In this embodiment, the incident angle of the electromagnetic wave is given as θ i1 and θ i2 According to the law of conservation of momentum, the seven outgoing electromagnetic wave angles in each rotation channel and the incident angle θ i3 The specific model relationship that can be established is shown in the following equation group:

[0085] 2kd sinθ i1 =ξ RL =ξ 0 +2ψ

[0086] 2kd sinθ i2 =ξ LR =ξ 0 -2ψ

[0087] 2kd sinθ i3 =ξ LL =ξ RR =ξ 0

[0088] kd(sinθ i1 +sinθ r1a )=ξ LR =ξ 0 -2ψ

[0089] kd(sinθ i1 +sinθ r1b )=ξ LL =ξ RR =ξ 0

[0090] kd(sinθ i1 +sinθ r1c )=ξ RL =ξ 0 +2ψ

[0091] kd(sinθ i2 +sinθ r2a )=ξ LR =ξ 0 -2ψ

[0092] kd(sinθ i2 +sinθ r2b )=ξ LL =ξ RR =ξ 0

[0093] kd(sinθ i2 +sinθ r2c)=ξ RL =ξ 0 +2ψ

[0094] kd(sinθ i3 +sinθ r3a )=ξ LR =ξ 0 -2ψ

[0095] kd(sinθ i3 +sinθ r3b )=ξ LL =ξ RR =ξ 0

[0096] kd(sinθ i3 +sinθ r3c )=ξ RL =ξ 0 +2ψ

[0097] Where k is the wave vector in free space, d is the metasurface unit period, Ψ is the unit rotation angle, ξ RL , LR , LL and RR are the functional phase distributions on the right-handed ← left-handed, left-handed ← right-handed, left-handed ← left-handed, and right-handed ← right-handed channels, and there is ξ LL =ξ RR =ξ 0 ,ξ RL =ξ 0 +2ψ and ξ LR =ξ 0 -2ψ.ξ 0 is the transmission phase when the unit is not rotated, θ ria ,θ rib ,θ ri The exit angles corresponding to the three different angles of incidence are shown in Table 1. The subscripts a, b, and c represent different rotation channels, respectively. a represents a left-handed ← right-handed channel, b represents a left-handed ← left-handed channel or a right-handed ← right-handed channel, and c represents a right-handed ← left-handed channel. i = 1, 2, and 3 correspond to the first incident angle θ. i1 , the second incident angle θ i2 and the third incident angle θ i3 situation.

[0098] By solving the above equations, the angle expressions of the seven outgoing electromagnetic waves are finally calculated as follows:

[0099] θ r1c =θ r2b =θ i1

[0100] θ r2a=θ r1b =θ i2

[0101] θ r3b =θ i3

[0102] θ r1a =arcsin(2sinθ i2 -sinθ i1 )

[0103] θ r2c =arcsin(2sinθ i1 -sinθ i2 )

[0104]

[0105]

[0106]

[0107] In the formula, θ r1a ,θ r1b ,θ r1c For function F 1 The corresponding three beam exit angles, θ r2a ,θ r2b ,θ r2c are the three corresponding beam exit angles in function F2, θ r3a ,θ r3b ,θ r3c For function F 3 The corresponding three beam exit angles.

[0108] In this embodiment, the lengths of the cross patches in the x and y directions are l respectively. x and l y , the periods of the metasurface unit along the x and y directions are p x and p y The lengths of the cross ring along the x and y directions are r x and r y , the width of the cross ring and the gap distance between the cross ring and the cross patch are d 1 and d 2 , w is the width of the cross patch. The structural parameters of each non-uniform metasurface unit are determined by the hybrid geometric phase and transmission phase design method.

[0109] Furthermore, the structural parameters of the metasurface unit include at least the length l of the cross patch in the x direction x and the length l of the cross patch in the y direction y, the structural parameters of the metasurface unit are determined by a hybrid geometric phase and transmission phase design method, which specifically includes:

[0110] Step A, within a preset range of variation, perform parameter scanning according to a preset step length, and establish the length l of the cross patch in the x direction under the excitation of the x-polarized wave and the y-polarized wave respectively. x and the length l of the cross patch in the y direction y The two-dimensional scanning phase matrix of the change is recorded as matrix PhaseX(l x ,l y ) and the matrix PhaseY(l x ,l y );

[0111] Specifically, the entire metasurface unit is modeled and the electromagnetic characteristics are simulated in CST software. Under the excitation of x and y polarized waves, the metasurface unit is subjected to a two-dimensional parameter scan, and the x and y polarizations with length l are stored. x and l y The changing two-dimensional scanning phase matrix PhaseX(l x ,l y ) and PhaseY(l x ,l y ).

[0112] First, according to the working frequency band and phase coverage requirements, the structural parameters are optimized and determined, including p x =p y =11mm, r x =r y =9mm, d 1 =d 2 =0.5mm and w=1mm.

[0113] Secondly, during the CST parameter scan, the above structural parameters are kept unchanged, and only the length l of the cross patch in the x and y directions is changed. x and l y , here l x and l y The preset variation range is (0.5~3.7mm), the simulation frequency band is 9~13GHz, 1001 frequency samples, and l x =0.5mm as the starting point, l y The scan starts from 0.5 to 3.7 mm, with a preset step length of 0.1 mm. After the scan is completed, the scan continues with l x =0.6mm as the starting point, l y From 0.6 to 3.7 mm, scan with a preset step length of 0.1 mm, and repeat until the last set of parameters l x =3.7mm, ly =3.7mm until the scanning is completed.

[0114] Step B, according to the given two cross-rotation channels, the retracement beam angle θ i1 and θ i2 And the number of metasurface units Nx*Ny, calculate the functional phase distribution ξ RL and LR ;

[0115] Specifically, in the two cross-rotation channels of right-handed ← left-handed and left-handed ← right-handed, the backtracking beam angle is θ i1 and θ i2 The backtracking function can calculate the functional phase distribution ξ in two cross-handed channels RL =2kd sinθ i1 and LR =2kdsinθ i2 .

[0116] In this embodiment, the metasurface function is set to be phase-only, and amplitude control is not considered. The amplitude of each part of the metasurface is uniform and approximately 1.

[0117] Step C, using the hand-direction decoupling method, according to the functional phase distribution ξ RL and LR , calculate the linear co-polarization phase distribution of each metasurface unit at the position in the integrated three-beam traceback array under x-polarization wave and y-polarization wave and and the geometric phase distribution 2Φ;

[0118] First, the relationship between the circular polarization transmission coefficient and the linear polarization transmission coefficient can be written as

[0119]

[0120]

[0121]

[0122]

[0123] In the formula, and They represent the x←y line cross-polarization conversion coefficient phase and the y←x line cross-polarization conversion coefficient phase, respectively. and They represent the phase of the y←y and x←x line co-polarization conversion coefficients respectively, r represents the amplitude, and the corresponding relationship between the specific amplitude parameters is inferred according to the phase parameter. The physical meaning of the circular polarization coefficients on the left side of the equation is similar to the definition of the linear polarization coefficients.

[0124] For a co-polarized system with axisymmetry along the x and y directions, the linear cross-polarization transmission coefficient r yx ≈r xy ≈0, co-polarization reflection coefficient r xx ≈r yy ≈1, the above formula can be further simplified to

[0125]

[0126]

[0127]

[0128]

[0129] From the phase term in the above equation, we can see that the L←L and R←R channels are not decoupled, while L←R, R←L and L←L or R←R are completely decoupled, forming three independent phase control channels. In order to ensure the independent control and multi-function of the three rotation channels in amplitude, it is required that the amplitudes of the circular polarization coefficients are equal and reach the maximum value, that is, Available At the same time, the above formula is equal to the phase terms of the first two formulas, so we can get two equations, plus For three unknowns and Φ are solved exactly as follows.

[0130]

[0131]

[0132]

[0133] In this embodiment,

[0134] Step D: Calculate the linear co-polarization phase distribution using the minimum Euclidean distance algorithm and With the matrix PhaseX(l x ,l y ) and the matrix PhaseY(l x ,l y ) and select the data corresponding to the minimum Euclidean distance δ as the length l of the cross patch in the x direction x and the length l of the cross patch in the y direction y , where the geometric phase distribution 2Φ is equal to twice the unit rotation angle Ψ.

[0135] Since the non-uniform metasurface units in this embodiment are only the length l of the cross patch x and l yThe length of the cross patch in the x and y directions is l. x and l y .

[0136] First, the minimum Euclidean distance algorithm is used to ensure that the obtained hypersurface topology has the minimum error. The established Euclidean distance δ function is:

[0137]

[0138] Will and All elements in the matrix are related to the two-dimensional scanning phase matrix PhaseX(l x ,l y ) and PhaseY(l x ,l y ) and each time the length l corresponding to the minimum Euclidean distance δ is selected x and l y , and the feedback is stored at the corresponding position (x, y) as the structural parameters of the cross patch of the metasurface unit at that location.

[0139] Furthermore, error evaluation can be performed by taking the length l of each selected hypersurface unit x and length l y The actual phase and ideal phase corresponding to the excitation of x and y polarized waves and Make a difference and find the error When the judgment error Less than the threshold δ 0 When the length l x and length l y As the length l of the final x-direction cross patch of the metasurface unit x and the length l of the cross patch in the y direction y When the judgment error Greater than or equal to the threshold δ 0 When the phase distribution of the linear co-polarization and Add a micro variable and repeat the above steps to optimize the structure.

[0140] Finally, structural modeling was carried out in the commercial simulation software CST. VBA macro modeling in CST and loop mapping were used to determine the topological structure of each unit in the final integrated three-beam traceback array, including the cross patch structure parameters and unit rotation angle.

[0141] Furthermore, the structural parameters of the super surface unit include at least: the period p of the super surface unit along the x directionx , the period of the hypertable unit along the y direction is p y , period p x and period p y All of them are less than the central operating frequency f of the integrated three-beam retracement array 0 The working wavelength λ 0 , where the period p x Equal to the period p y , and the period p x Less than λ 0 / 3.

[0142] Specifically, set the unit period p x =p y =d, the design principle is to make p x and p y Less than the center operating frequency f 0 The working wavelength at the sub-wavelength characteristic d<λ 0 / 3.

[0143] In this embodiment, the two-layer composite metal structure is sequentially recorded as the first composite metal structure and the second composite metal structure, a first dielectric plate is arranged between the first composite metal structure and the second composite metal structure, and a second dielectric plate is arranged between the second composite metal structure and the bottom metal back plate, wherein the first dielectric plate and the second dielectric plate have the same thickness. Both dielectric plates are polytetrafluoroethylene glass cloth plates, and the dielectric constant is ε r =2.65, the tangent loss is tanδ=0.001, and the thickness is h=2.5mm.

[0144] Embodiment three:

[0145] Based on the above embodiments, Figure 4 As shown, this embodiment provides a design method for an integrated three-beam backtracking array, comprising the following steps:

[0146] Step 1, determine the structure and structural parameters of the integrated three-beam back-tracing array, wherein the structure of the integrated three-beam back-tracing array includes a plurality of metasurface units, wherein the metasurface units are provided with nested cross rings and cross patches, wherein the cross patches include x-direction cross patches and y-direction cross patches, and the structural parameters include the number of metasurface units Nx*Ny and the length l of the x-direction cross patches x , the length of the cross patch in the y direction l y .

[0147] Step 2: Perform parameter scanning according to the preset step length within the preset variation range to establish the length l of the cross patch along the x direction under the excitation of the x-polarized wave and the y-polarized wave respectively. x and the length l of the cross patch in the y direction yThe two-dimensional scanning phase matrix of the change is recorded as matrix PhaseX(l x ,l y ) and the matrix PhaseY(l x ,l y );

[0148] like Figure 1 As shown, the function F of the integrated three-beam backtracking array in this embodiment 1 , F 2 and F 3 In addition to the backtracking beam, two other reflected beams at other angles are included in the remaining rotational channels, including the backtracking beam, forming a total of 7 outgoing beams with different angles, which are represented by different line types. According to the calculation formula in the claims, the specific values ​​of the 7 different angles can be calculated, including the backtracking angle θ of the third backtracking beam. i3 =22.3°.

[0149] For example, for F 1 , the electromagnetic wave travels along θ i1 =30° direction, in the right-handed←left-handed channel, along θ i1 =θ r1c =30° The tracing beam returning along the original path is along θ in the right-handed ← right-handed or left-handed ← left-handed channel. r1b =15° reflected outgoing beam, and on the left-handed←right-handed channel along θ r1a = 1° reflected outgoing beam; for F 2 , the electromagnetic wave travels along θ i2 =15° direction, in the left-handed←right-handed channel, along θ i2 =θ r2a = 15° The tracing beam returning along the original path is along θ in the right-handed ← right-handed or left-handed ← left-handed channel. r2b =30° reflected outgoing beam, and on the right-handed←left-handed channel along θ r2c =47.8° reflected outgoing beam; for F 3 , the electromagnetic wave travels along θ i3 = 22.3° direction, in the right-handed ← right-handed or left-handed ← left-handed channel, the i3 =θ r3b = 22.3° The tracing beam returns along the original path, and on the left-handed←right-handed channel, it is along θ r3a =7.9° reflected outgoing beam, and on the right-handed←left-handed channel along θ r3c =38.3° reflected outgoing beam.

[0150] With θ i1 =30°,θ i2 =15° and θ i3 =22.3°, we can calculate theRL =2kdsinθ i1 and LR =2kdsinθ i2 Calculate ξ RL ,ξ LR The phase distribution of and Counter-performance With Φ distribution, such as Figure 5 shown.

[0151] Then, a suitable anisotropic metasurface unit structure is designed. The metasurface unit consists of two layers of composite metal structure and a bottom metal backplane. The three layers of metal structure are separated by two layers of dielectric plates with a height of h. The composite metal structure is composed of an external cross ring and an internal cross patch, and the cross ring is nested with a cross patch. The length of the cross patch in the x and y directions is l x and l y , the periods of the unit along the x and y directions are p x and p y The lengths of the cross ring along the x and y directions are r x and r y , the width of the cross ring and the gap distance between the cross ring and the cross patch are d 1 and d 2 , w is the width of the cross patch.

[0152] The entire composite metasurface unit is modeled and its electromagnetic properties are simulated in CST software. Two-dimensional parameter scanning is performed on the metasurface unit under x- and y-polarized wave excitation. x and l y Changing two-dimensional amplitude scanning matrix Amp x (l x ,l y ) and Amp y (l x ,l y ) and the phase matrix PhaseX((l x ,l y ) and PhaseY(l x ,l y ).

[0153] When scanning the CST parameters, other structural parameters are kept unchanged, namely: p x =p y =11mm, r x =r y =9mm, d 1 =d 2=0.5mm and w=1mm, only the length l of the cross patch in the x and y directions is changed x and l y , here l x and l y The preset variation range is (0.5~3.7mm), the simulation frequency band is 9~13GHz, 1001 frequency samples, and l x =0.5mm as the starting point, l y The scan starts from 0.5 to 3.7 mm, with a preset step length of 0.1 mm. After the scan is completed, the scan continues with l x =0.6mm as the starting point, l y From 0.6 to 3.7 mm, scan with a preset step length of 0.1 mm, and repeat until the last set of parameters l x =3.7mm, l y =3.7mm until the scanning is completed.

[0154] Figure 6 and Figure 7 The two-dimensional collinear polarization reflection amplitude and phase scan databases of the unit at three frequencies of 10 GHz, 10.5 GHz and 11 GHz are given respectively. From the amplitude spectrum, it can be seen that l is visible in all cases of x and y polarization. x or y The amplitude is low at a certain position in the middle, corresponding to the vicinity of the unit resonance, and the reflection amplitude decreases. Moreover, as the observation frequency increases, the low amplitude area moves toward l x or y Reduce the directional movement, such as 10GHz, 10.5GHz and 11GHz, the low amplitude area corresponds to l x or y =2.7mm, 2.4mm and 2.1mm, which conforms to the natural physical law that the size decreases and the resonant frequency increases.

[0155] Nevertheless, the reflection amplitude of the unit in all cases is above 0.95, so that the traceback array design can be carried out without paying attention to the amplitude but only the phase. It can be seen from the phase spectrum that the specific l under x and y polarization x and l y The corresponding phase wave front is not horizontal, and the equal phase line has certain fluctuations, indicating that there is a certain phase error under the orthogonal polarization crosstalk, that is, the change l under x polarization y Will give Causes error, or changes l under y polarization x Will give This leads to errors, which and Cannot be based on l x and l yThe phase control range increases with the increase of frequency. For example, at 10 GHz, 10.5 GHz and 11 GHz, the phase control range reaches 332°, 356° and 426° respectively.

[0156] Step 3: according to the given two cross-rotation channels, the retracement beam angle θ i1 and θ i2 And the number of metasurface units Nx*Ny, calculate the functional phase distribution ξ RL and LR ;

[0157] Step 4: Use the rotational decoupling method to calculate the functional phase distribution ξ RL and LR , calculate the linear co-polarization phase distribution of the metasurface unit at each position in the integrated three-beam traceback array under x-polarized waves and y-polarized waves and And the geometric phase distribution 2Φ; where the linear co-polarization phase distribution and And the calculation formula of geometric phase distribution 2Φ is:

[0158]

[0159]

[0160]

[0161]

[0162] In the formula, is the first parameter, is the second parameter.

[0163] Step 5: Use the minimum Euclidean distance algorithm to calculate the linear co-polarization phase distribution and With the matrix PhaseX(l x ,l y ) and the matrix PhaseY(l x ,l y ) and select the data corresponding to the minimum Euclidean distance δ as the length l of the cross patch in the x direction x and the length l of the cross patch in the y direction y ;

[0164] In this embodiment, a mathematical model is established to obtain the minimum Euclidean distance to ensure that the obtained topological structure has the minimum error. Figure 5 The corresponding and All elements in the matrix are Figure 7 The two-dimensional scanning phase matrix PhaseX(l x ,l y ) and PhaseY(l x ,l y ) and each time select the l corresponding to the minimum Euclidean distance δ x and l y The feedback is stored at the position (x, y) as the structural parameters of the unit cross patch at that location.

[0165] To further improve the modeling accuracy, the length l of two adjacent x-direction cross patches selected within a preset range of variation according to a preset step size is x and the length l of the cross patch in the y direction y Perform two-dimensional interpolation processing, that is, first scan the two-dimensional phase matrix PhaseX(l x ,l y ) and PhaseY(l x ,l y ) performs two-dimensional interpolation and converts l x and l y The step size of (0.5 to 3.7 mm) is improved to 0.025 mm by interpolation.

[0166] At the same time, the length l of each selected hypersurface unit can also be x and length l y The actual phase and ideal phase corresponding to the excitation of x and y polarized waves and Make a difference and find the error When the judgment error Less than the threshold δ 0 When the length l x and length l y As the length l of the final x-direction cross patch of the metasurface unit x and the length l of the cross patch in the y direction y , then execute step 6; when the error is determined Greater than or equal to the threshold δ 0 When the phase distribution of the linear co-polarization and Add a micro variable and re-execute step 5 to optimize the structure.

[0167] Figure 8The one-dimensional collinear polarization phase error of the integrated three-beam retrieval array is given, that is, the error between the phase corresponding to the actual structure and the ideal calculated phase. Since the integrated three-beam retrieval array repeats periodically in another dimension, the error will also repeat periodically, so it will not be repeated. It can be seen that The error range is -2.8°~22.5°. The error range is -3.9°~12.3°, and the effect of this error level on the function and efficiency can be ignored.

[0168] Fig. 9 The integrated three-beam traceback array is given in one dimension x and l y Value, we can see that l x and l y Maintain a certain relationship in a constant change to ensure

[0169] Figure 2 The final topological structure of the integrated three-beam traceback array is given. It can be seen that the unit structure is only along one dimension, such as along the x direction l x , l y The parameters and the rotation angle Φ are constantly changing, while along the other orthogonal dimension, the periodic repetition is maintained along the y direction.

[0170] Step 6: According to the length l of the cross patch in the x direction x and the length l of the cross patch in the y direction y The size of the cross patch is determined, and the unit rotation angle of the cross patch is determined according to the geometric phase distribution 2Φ to form an integrated three-beam traceback array.

[0171] In this embodiment, the structural parameters of the super surface unit include at least: the period p of the super surface unit along the x direction x , the period of the hypertable unit along the y direction is p y , period p x and period p y All of them are less than the central operating frequency f of the integrated three-beam retracement array 0 The working wavelength λ 0 . Among them, the period p x Equal to the period p y , and the period p x Less than λ 0 / 3.

[0172] Specifically, the unit period p is determined according to the working frequency band. x =p y =d, the design principle is to make p x and p y Less than the center operating frequency f 0 The working wavelength at the sub-wavelength characteristic d<λ0 / 3.

[0173] Fig.10 and Fig.11 The simulated three-dimensional scattering pattern of the integrated three-beam back-tracing array and the simulated two-dimensional scattering pattern in the xoz main plane are given respectively. It can be seen that θ i1 =30°,θ i2 =15° and θ i3 =22.3°, a single-mode efficient scattering is effectively achieved in four different handedness channels in three cases, where the beam scattering angles are the same on the right-handed←right-handed and left-handed←left-handed channels, and in each case there is a beam scattering angle that is the same as the incident angle, which is a traceback beam.

[0174] Therefore, the integrated three-beam tracing array in this embodiment includes not only three tracing beams, but also two reflected beams at other angles on the remaining rotational channels.

[0175] Specifically, the electromagnetic wave along θ i1 =30°, in the right-handed←left-handed channel, along θ i1 =θ r1c =30° The tracing beam returning along the original path is along θ in the right-handed ← right-handed or left-handed ← left-handed channel. r1b =15° reflected outgoing beam, and on the left-handed←right-handed channel along θ r1a = 1° reflected outgoing beam; electromagnetic wave along θ i2 =15°, in the left-handed←right-handed channel, along θ i2 =θ r2a = 15° The tracing beam returning along the original path is along θ in the right-handed ← right-handed or left-handed ← left-handed channel. r2b =30° reflected outgoing beam, and on the right-handed←left-handed channel along θ r2c =47.8° reflected outgoing beam; electromagnetic wave along θ i3 = 22.3°, in the right-handed ← right-handed or left-handed ← left-handed channel, along θ i3 =θ r3b = 22.3° The tracing beam returns along the original path, and on the left-handed←right-handed channel, it is along θ r3a =7.9° reflected outgoing beam, and on the right-handed←left-handed channel along θ r3c =38.3° reflected outgoing beam.

[0176] In summary, in all cases, the simulation results are completely consistent with the theoretical calculation results, verifying the correctness of the integrated three-beam traceback array and its design in this embodiment, and the efficiency of the single-mode scattering beam is as high as 100%.

[0177] The technical solution of the present application is described in detail above in combination with the accompanying drawings. The present application proposes an integrated three-beam tracing array and a design method thereof, wherein the integrated three-beam tracing array is composed of a plurality of metasurface units, and the metasurface units include two layers of composite metal structures with the same structure arranged in sequence and a layer of bottom metal backplane, and the composite metal structure includes: a cross ring and a cross patch; the cross patch is nested inside the cross ring, and the center line of the cross patch coincides with the center line of the cross ring, and the cross ring is tilted according to the unit rotation angle, wherein the metasurface unit is periodically repeated along the y direction. In addition to realizing three-beam tracing, the integrated three-beam tracing array can also realize two additional reflected beams with different angles in other rotational channels under three different incident angles, including tracing beams to form a total of 7 outgoing beams with different angles, and has the advantages of high integration, large channel capacity and easy processing of planar structure.

[0178] The steps in this application can be adjusted in order, combined, and deleted according to actual needs.

[0179] The units in the device of the present application can be combined, divided and deleted according to actual needs.

[0180] Although the present application is disclosed in detail with reference to the accompanying drawings, it should be understood that these descriptions are merely exemplary and are not intended to limit the application of the present application. The scope of protection of the present application is defined by the appended claims and may include various modifications, alterations and equivalents made to the invention without departing from the scope and spirit of the present application.

Claims

1. Integrated three-beam backtracking array, characterized in that: The integrated three-beam backtracking array is composed of a plurality of metasurface units, wherein the metasurface units include two layers of composite metal structures with the same structure arranged in sequence and a bottom metal backplane, wherein the composite metal structure includes: a cross ring and a cross patch; The cross patch is nested inside the cross ring, the center line of the cross patch coincides with the center line of the cross ring, the cross patch and the cross ring are tilted according to the unit rotation angle, wherein the metasurface unit is periodically repeated along the y direction, When the electromagnetic wave is incident on the integrated three-beam tracing array at three different angles, the reflected beam of the electromagnetic wave is emitted at the same angle as the incident angle, realizing the three-tracing beam function, and the three-tracing beam function occurs in different rotation channels, which are respectively recorded as right-handed ← left-handed channel, left-handed ← right-handed channel and right-handed ← right-handed channel, or, Right-handed ← left-handed channel, left-handed ← right-handed channel, and left-handed ← left-handed channel.

2. The integrated three-beam backtracking array according to claim 1, characterized in that: The three different incident angles of the electromagnetic wave include a given first incident angle θ i1 and the second incident angle θ i2 , the electromagnetic wave emission angle in each rotation channel of the integrated three-beam tracing array and the third incident angle θ i3 Determined by the law of conservation of momentum, the corresponding calculation formula is: 2kd synth i1 =ξ RL =ξ0+2ψ 2kd synth i2 =ξ LR =ξ0-2ψ 2kd synth i3 =ξ LL =ξ RR =ξ0 kd(sinθ i1 +sinθ r1a )=ξ LR =ξ0-2ψ kd(sinθ i1 +sinθ r1b )=ξ LL =ξ RR =ξ0 kd(sinθ i1 +sinθ r1c )=ξ RL =ξ0+2ψ kd(sinθ i2 +sinθ r2a )=ξ LR =ξ0-2ψ kd(sinθ i2 +sinθ r2b )=ξ LL =ξ RR =ξ0 kd(sinθ i2 +sinθ r2c )=ξ RL =ξ0+2ψ kd(sinθ i3 +sinθ r3a )=ξ LR =ξ0-2ψ kd(sinθ i3 +sinθ r3b )=ξ LL =ξ RR =ξ0 kd(sinθ i3 +sinθ r3c )=ξ RL =ξ0+2ψ Where k is the wave vector in free space, d is the period of the metasurface unit, Ψ is the rotation angle of the unit, ξ RL , LR , LL and RR are the functional phase distributions on the right-handed ← left-handed channel, the left-handed ← right-handed channel, the left-handed ← left-handed channel, and the right-handed ← right-handed channel, ξ0 is the transmission phase when the unit is not rotated, θ ria ,θ rib ,θ ric are the exit angles corresponding to three different incident angles, the subscripts a, b, and c represent different said handedness channels, a represents a left-handed ← right-handed channel, b represents a left-handed ← left-handed channel or a right-handed ← right-handed channel, and c represents a right-handed ← left-handed channel, i=1, 2, 3, corresponding to the first incident angle θ respectively i1 The second incident angle θ i2 And the third incident angle θ i3 situation.

3. The integrated three-beam backtracking array according to claim 1, characterized in that: The calculation formula for the electromagnetic wave emission angle in the integrated three-beam tracing array is: i r1c =θ r2b =θ i1 i r2a =θ r1b =θ i2 i r3b =θ i3 i r1a =arcsin(2sinθ i2 -sinθ i1 ) i r2c =arcsin(2sinθ i1 -sinθ i2 ) In the formula, θ ria ,θ rib ,θ ric are the exit angles corresponding to the three different incident angles, the subscripts a, b, and c represent the different rotation channels, a represents the left-handed ← right-handed channel, b represents the left-handed ← left-handed channel or the right-handed ← right-handed channel, and c represents the right-handed ← left-handed channel. i = 1, 2, and 3, respectively, are the corresponding first incident angles θ i1 , the second incident angle θ i2 and the third incident angle θ i3 situation.

4. The integrated three-beam traceback array according to any one of claims 1 to 3, characterized in that: The two layers of the composite metal structure are respectively recorded as a first composite metal structure and a second composite metal structure, a first dielectric plate is arranged between the first composite metal structure and the second composite metal structure, and a second dielectric plate is arranged between the second composite metal structure and the bottom metal back plate, wherein the first dielectric plate and the second dielectric plate have the same thickness.

5. The integrated three-beam traceback array according to claim 1, characterized in that: The cross patch includes an x-direction cross patch and a y-direction cross patch, and the structural parameters of the metasurface unit at least include the length l of the x-direction cross patch x and the length l of the cross patch in the y direction y , the structural parameters of the metasurface unit are determined by a hybrid geometric phase and transmission phase design method, and the hybrid geometric phase and transmission phase design method specifically includes: Step A, within a preset range of variation, perform parameter scanning according to a preset step length, and establish the length l of the cross patch in the x direction under the excitation of the x-polarized wave and the y-polarized wave respectively. x and the length l of the cross patch in the y direction y The two-dimensional scanning phase matrix of the change is recorded as matrix PhaseX(l x , l y ) and the matrix PhaseY(l x , l y ); Step B, according to the given two cross-rotation channels, the retracement beam angle θ i1 and θ i2 And the number of metasurface units Nx*Ny, calculate the functional phase distribution ξ RL and LR ; Step C, using the hand-direction decoupling method, according to the functional phase distribution ξ RL and LR , calculate the linear co-polarization phase distribution of each of the metasurface units at the position in the integrated three-beam traceback array under the x-polarized wave and the y-polarized wave and and the geometric phase distribution 2Φ; Step D, using the minimum Euclidean distance algorithm to calculate the linear co-polarization phase distribution and With the matrix PhaseX(l x , l y ) and the matrix PhaseY(l x , l y ), and select the data corresponding to the minimum Euclidean distance as the length l of the cross patch in the x direction x and the length l of the cross patch in the y direction y , The geometric phase distribution 2Φ is equal to twice the unit rotation angle Ψ.

6. The integrated three-beam traceback array according to claim 1, characterized in that: The structural parameters of the super surface unit include at least: The period p of the metasurface unit along the x direction x , the period p of the metasurface unit along the y direction y , the period p x and the period p y They are all smaller than the working wavelength λ0 at the central working frequency f0 of the integrated three-beam traceback array.

7. The integrated three-beam traceback array according to claim 6, characterized in that: The period p of the metasurface unit along the x direction x is equal to the period p of the metasurface unit along the y direction y , the period p of the metasurface unit along the x direction x Less than 1 / 3 of the working wavelength λ0; The structural parameters of the super surface unit also include: The length r of the cross ring along the x and y directions x and r y , r x =r y =9mm, The width of the cross ring is d1, d1 = 0.5 mm, The gap distance between the cross ring and the cross patch is d2, d2 = 0.5 mm, The width w of the cross patch is w=1 mm.

8. A design method for an integrated three-beam backtracking array, characterized in that: The method includes: Step 1, determining the structure and structural parameters of the integrated three-beam backtracking array, The structure of the integrated three-beam backtracking array includes a plurality of metasurface units, wherein the metasurface units are provided with nested cross rings and cross patches, wherein the cross patches include x-direction cross patches and y-direction cross patches, and the structural parameters include the number of the metasurface units Nx*Ny; Step 2: Perform parameter scanning according to a preset step length within a preset variation range to establish the length l of the cross patch along the x direction under the excitation of the x-polarized wave and the y-polarized wave. x and the length l of the cross patch in the y direction y The two-dimensional scanning phase matrix of the change is recorded as matrix PhaseX(l x , l y ) and the matrix PhaseY(l x , l y ); Step 3: according to the given two cross-rotation channels, the backtracking beam angle θ i1 and θ i2 And the number of metasurface units Nx*Ny, calculate the functional phase distribution ξ RL and LR ; Step 4: using the hand-direction decoupling method, according to the functional phase distribution ξ RL and LR , calculate the linear co-polarization phase distribution of the metasurface unit at each position in the integrated three-beam traceback array under the x-polarized wave and the y-polarized wave and and the geometric phase distribution 2Φ; Step 5: Calculate the linear co-polarization phase distribution using the minimum Euclidean distance algorithm and With the matrix PhaseX(l x , l y ) and the matrix PhaseY(l x , l y ), and select the data corresponding to the minimum Euclidean distance as the length l of the cross patch in the x direction x and the length l of the cross patch in the y direction y ; Step 6: According to the length l of the cross patch in the x direction x and the length l of the cross patch in the y direction y The size of the cross patch is determined, and the unit rotation angle of the cross patch is determined according to the geometric phase distribution 2Φ to form the integrated three-beam traceback array.

9. The design method of the integrated three-beam backtracking array as claimed in claim 8, characterized in that: The step 5 also includes: The length l of each selected hypersurface unit x and length l y The actual phase and ideal phase corresponding to the excitation of x and y polarized waves and Make a difference and find the error When determining the error When it is less than the threshold δ0, the length l x and length l y As the length l of the final x-direction cross patch of the metasurface unit x and the length l of the cross patch in the y direction y , then execute step 6; When determining the error When the linear co-polarization phase distribution is greater than or equal to the threshold δ0, and Add a micro variable and repeat step 5.

10. The design method of the integrated three-beam traceback array according to claim 8, characterized in that: The step 2 also includes: The length l of two adjacent x-direction cross patches selected within the preset variation range according to the preset step length is x and the length l of the cross patch in the y direction y Perform two-dimensional interpolation.

11. The design method of the integrated three-beam traceback array according to claim 8, characterized in that: The linear co-polarization phase distribution and And the calculation formula of geometric phase distribution 2Φ is: In the formula, is the first parameter, is the second parameter.

12. The design method of the integrated three-beam traceback array according to claim 8, characterized in that: The structural parameters of the super surface unit include at least: The period p of the metasurface unit along the x direction x , the period p of the metasurface unit along the y direction y , the period p x and the period p y They are all smaller than the working wavelength λ0 at the central working frequency f0 of the integrated three-beam traceback array.

13. The design method of the integrated three-beam traceback array according to claim 12, characterized in that: The period p of the metasurface unit along the x direction x is equal to the period p of the metasurface unit along the y direction y , the period p of the metasurface unit along the x direction x Less than 1 / 3 of the working wavelength λ0; The structural parameters of the super surface unit also include: The length r of the cross ring along the x and y directions x and r y , r x =r y =9mm, The width of the cross ring is d1, d1 = 0.5 mm, The gap distance between the cross ring and the cross patch is d2, d2 = 0.5 mm, The width w of the cross patch is w=1 mm.

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