Spin independent amplitude and phase coherence method and reconfigurable multifunctional device

Abstract

The application belongs to the technical field of electromagnetic multifunctional metasurface, and particularly relates to a method for independently adjusting the amplitude and phase of rotation and a reconfigurable multifunctional device; the reconfigurable multifunctional device is composed of M*N metasurface units, and each metasurface unit is composed of four metal structure layers and three dielectric layers; the metal structure layers are respectively an active adjustable circular arc metal resonator structure, a metal ground plate with a closed circular groove, a variable resistance diode and a switching diode feeding line layer; under the working circularly polarized wave, the amplitude and phase of the outgoing electromagnetic wave can be controlled by changing the states of the variable resistance diode and the switching diode, so that the function reconfiguration is realized; and by changing the states of the switching diodes on different circular open rings, the two cross circular polarization channels can be completely decoupled under the same working frequency band; the application has the advantages of high efficiency, high integration and reconfiguration.

Description

Technical Field

[0001] This invention belongs to the field of electromagnetic multifunctional metasurface technology, and specifically relates to a method for amplitude and phase co-homogenization with independent rotation direction and a reconfigurable multifunctional device. Background Technology

[0002] Two-dimensional metasurfaces can be considered as two-dimensional forms of metamaterials, composed of subwavelength units arranged periodically or aperiodically. In recent years, metasurfaces have been widely used in electromagnetic wave polarization, amplitude, and phase modulation due to their powerful electromagnetic manipulation capabilities, becoming candidate materials for designing electromagnetic functional devices. Among these, to meet the demands of electromagnetic devices for intelligence and environmental adaptability, a series of reconfigurable metasurface devices have been designed and reported. However, most reported reconfigurable metasurfaces are currently limited to reconfigurable control of the phase of the emitted electromagnetic wave, lacking the degree of freedom of amplitude modulation. This significantly weakens the metasurface's ability to control spatial electromagnetic waves, and also greatly affects performance aspects such as efficiency and accuracy. Therefore, subsequent work has begun to design and research reconfigurable metasurfaces based on simultaneous amplitude and phase modulation. These metasurfaces can achieve independent modulation of the phase and amplitude of emitted circularly polarized (CP) electromagnetic waves through different diode modulation mechanisms, realizing highly flexible and dynamically tunable electromagnetic wave functions.

[0003] However, most reported reconfigurable metasurfaces based on simultaneous amplitude and phase modulation currently operate under a single polarization wave incidence, failing to achieve multifunctional integration and co-modulation of polarization under reconfigurable conditions. This results in a significant waste of polarization resources. The design methods for realizing reconfigurable metasurfaces based on rotation-independent amplitude and phase modulation are still in their infancy, and their working mechanisms remain unclear. There is an urgent need to find a rotation-independent amplitude and phase co-modulation method and reconfigurable multifunctional devices. Summary of the Invention

[0004] Specifically, the purpose of this invention is to propose a reconfigurable metasurface multifunctional device and its design method that can dynamically and independently control the phase and amplitude of electromagnetic waves under different CP wave incident conditions.

[0005] This invention proposes a method for achieving rotation-independent amplitude and phase co-homogeneity, which includes the following steps:

[0006] Step 1: Introduce active tunable arc-shaped metal resonator structure, switching diode, variable resistance diode and other elements into the metasurface unit design of reconfigurable multifunctional device, and construct phase and amplitude independent control modes under the left-to-right circular polarization LR and right-to-left circular polarization RL channels under the same operating frequency band.

[0007] Step 2: Determine the structural parameters of the adjustable arc-shaped metal resonator, the model parameters of the switching diode and the variable resistor diode according to the predetermined operating frequency band, set the function of the reconfigurable multifunctional device under different cycloid polarization wave incident and calculate the corresponding phase and amplitude distribution.

[0008] The functions include one-dimensional or two-dimensional deflection function, non-uniform multi-beam function, and holographic imaging function.

[0009] Step 3: Based on the predetermined function and the calculated phase and amplitude distribution, determine the topology of the reconfigurable multifunctional device, that is, the state of the diode on each metasurface unit on the aperture, to realize the reconfigurable multifunctional device.

[0010] The reconfigurable multifunctional device is composed of M*N metasurface units with different diode state distributions arranged in a plane with equal spacing and periodic extension.

[0011] The metasurface unit includes a first metal layer, a second metal layer, a third metal layer, and a fourth metal layer, with the three dielectric substrates directly disposed on the metal layers;

[0012] The first metal layer includes two vertically symmetrical circular open rings and two metal strips. Each circular open ring has a variable resistor diode and a switching diode connected in series. The two circular open rings are connected at their tail ends and connected to the metal strips. The third and fourth metal layers are the feed layers for the variable resistor diode and the switching diode, respectively, and their metal structures are rectangular pointing in the y-direction. The second metal layer is a metal ground plane with etched closed circular grooves.

[0013] The metasurface unit controls the amplitude and phase of electromagnetic waves emitted in different directions by changing the state of the diodes on different circular open rings, thereby realizing non-uniform multi-beam or holographic imaging functions in the left-to-right circular polarization (LR) or right-to-left circular polarization (RL) channels. Furthermore, by simultaneously changing the state of the diodes on the two circular open rings, the functions of the two cross-circular polarization channels can be superimposed when the linearly polarized wave is incident.

[0014] Furthermore, in step 2, the one-dimensional or two-dimensional deflection function, based on the generalized Snell's theorem, calculates the metasurface phase distribution, and the relationship between the electromagnetic wave reflection phase under a single beam deflection function satisfies:

[0015]

[0016] It is a free-space wave vector. The wavelength corresponding to the operating frequency; It is the reflection phase of the (i, j)th unit; and It represents the distance of the (i, j)th element from the x-axis and y-axis in the Cartesian coordinate system; i is the element in the x-direction of the two-dimensional plane coordinate system, and j is the element in the y-direction of the two-dimensional plane coordinate system. and These are the elevation and azimuth angles of the emitted circularly polarized wave, respectively. This is the initial phase of the metasurface center unit, set to 0° here.

[0017] Furthermore, in step 2, the non-uniform multi-beam function calculates the final continuous amplitude distribution A and phase distribution by setting the normalized reflection coefficient matrix of each outgoing beam and applying the superposition principle to multiple deflected beams based on the complex reflection coefficient matrix. ;

[0018] The complex reflection coefficient matrix of the two deflected beams is and The complex reflection coefficient matrix after superposition is: The expressions and superposition rules of the three are as follows:

[0019]

[0020]

[0021]

[0022]

[0023] in, This represents the amplitude distribution required to achieve the first wavenumber deflection function. This represents the amplitude distribution required to achieve the second wavenumber deflection function. This represents the amplitude distribution required to achieve the third wavenumber deflection function. This represents the phase distribution required to achieve the first wavenumber deflection function. This represents the phase distribution required to achieve the second wavenumber deflection function. This represents the phase distribution required when two wavenumber deflection functions are superimposed. N represents the number of rows of metasurface units in a reconfigurable metasurface multifunctional device, and N represents the number of columns of metasurface units in the reconfigurable metasurface multifunctional device. (n) represents the coordinates of any metasurface unit in a reconfigurable metasurface multifunctional device. Represents the imaginary unit;

[0024] Since some values ​​in the amplitude distribution calculated by linear superposition are greater than 1, which does not comply with the requirement that values ​​in the amplitude distribution must be less than or equal to 1, it is necessary to normalize the maximum value of the amplitude distribution.

[0025]

[0026] This represents the amplitude distribution after final normalization required to achieve the third wavenumber deflection function.

[0027] Furthermore, in step 2, the non-uniform multi-beam function also includes a non-uniform four-beam function and a non-uniform eight-beam function.

[0028] For the aforementioned non-uniform four-beam function, the following steps are included:

[0029] First, the elevation angle, azimuth angle, and normalized reflection amplitude weights of the four beams are set to (45°, 0°, 1), (30°, 90°, 0.7), (45°, 180°, 1), and (30°, 270°, 0.7), respectively.

[0030] Secondly, by using the generalized Snell's theorem and the principle of superposition of complex reflection amplitude weights, the continuous phase distribution and amplitude distribution of the desired function can be obtained;

[0031] Finally, the continuous phase and amplitude distributions obtained above are normalized, and the normalized phase and amplitude distributions are encoded with 1 bit and 2 bits respectively to obtain the final discrete phase and amplitude distributions.

[0032] Furthermore, in step 2, the non-uniform eight-beam function includes the following steps:

[0033] First, the elevation angle, azimuth angle, and normalized reflection amplitude weights of the eight beams are set as (45°, 0°, 1), (30°, 90°, 0.5), (45°, 180°, 1), (30°, 270°, 0.5), (30°, 0°, 1), (45°, 90°, 0.7), (30°, 180°, 1), and (45°, 270°, 0.7), respectively.

[0034] Secondly, the first four beams and the last four beams are assigned as two functions, respectively, to the left-to-right circularly polarized LR and the right-to-left circularly polarized RL channels.

[0035] Next, the discrete phase distribution and amplitude distribution of a specific function under the two channels were calculated respectively;

[0036] Finally, the phase and amplitude are encoded using 1 bit of phase encoding and 2 bits of amplitude encoding.

[0037] Furthermore, in step 2, the holographic imaging function first converts the two-dimensional image being imaged into a two-dimensional numerical matrix of the electric field distribution of the imaging surface.

[0038] The phase and amplitude distribution required to calculate the metasurface:

[0039]

[0040] In the formula, and Let represent the two-dimensional numerical matrices of the electric field distribution on the holographic surface and the imaging surface, respectively. and k represent the operating wavelength and the wave number in free space, respectively, and n represents the nth unit. On the meta-holographic plane ( , , 0) onto the imaging plane ( , The distance of F) The imaging region is defined as i, where i is the imaginary unit.

[0041] The electric field distribution of the reconstructed image on the imaging plane is calculated using the Fast Fourier Transform algorithm. Electric field distribution on:

[0042]

[0043] After obtaining the electric field distribution of the holographic surface, its basic form can be obtained using... This indicates that further solving for the phase components in the electric field is necessary. and amplitude components That is, continuous phase distribution and amplitude distribution. The continuous phase distribution and amplitude distribution are normalized and the phase and amplitude are encoded. 1 bit phase encoding and 2 bit amplitude encoding are used to obtain the final discrete phase distribution and amplitude distribution. The final required amplitude and phase distribution are then assigned to the left-to-right circularly polarized LR and right-to-left circularly polarized RL channels, respectively.

[0044] Furthermore, in step 2, the phase distribution and amplitude distribution undergo normalized data processing and encoding, including:

[0045] First, the amplitude distribution and phase distribution are normalized to the maximum values ​​of 1 and 360, respectively.

[0046] Secondly, the normalized amplitude distribution is encoded using 2 bits:

[0047] When the amplitude value is greater than or equal to 0 and less than 0.25, set it to 0.25; when the amplitude value is greater than or equal to 0.25 and less than 0.5, set it to 0.5; when the amplitude value is greater than or equal to 0.5 and less than 0.75, set it to 0.75; when the amplitude value is greater than or equal to 0.75 and less than 0.95, set it to 0.95.

[0048] Finally, the normalized phase distribution is encoded using 1 bit:

[0049] When the phase value is greater than or equal to 0° and less than 180°, set it to 0°; when the phase value is greater than or equal to 180° and less than 360°, set it to 180°.

[0050] Furthermore, step 3 also includes:

[0051] First, based on the phase and amplitude distributions, the state distributions of the two diodes corresponding to each phase and amplitude distribution under different CP wave incident conditions are identified. A 180° phase corresponds to the "on" state of the switching diode and is represented by '1', while a 0° phase corresponds to the "off" state of the switching diode and is represented by '0'. Based on these states, the FPGA output preamplifier voltage is ultimately determined to be either high or low. Four states in the amplitude encoding—0.95, 0.75, 0.5, and 0.25—are set, each corresponding to an equivalent resistance value. The values ​​are 3Ω, 50Ω, 140Ω, and 300Ω. Based on the equivalent resistance and the resistance-preamplifier current relationship curve of the variable resistor diode, the required low-frequency preamplifier current for the FPGA output can be calculated, which are 25 mA, 0.7 mA, 0.26 mA, and 0.14 mA, respectively.

[0052] Finally, by using different polarization feed sources to excite metasurface integrated devices, holographic imaging and non-uniform multi-beam functionality are achieved under different combinations of two diode states when CP wave incident, as well as the superposition of electromagnetic wave functions under left-hand to right-hand cross-circular polarization LR and right-hand to left-hand cross-circular polarization RL channels when LP wave incident. Furthermore, by outputting corresponding low-frequency pre-voltage and pre-current through FPGA to control the "on" and "off" states of the switching diodes and the equivalent resistance of the variable resistor diodes, the non-uniform multi-beams can be arbitrarily switched in terms of quantity, direction, and amplitude. This also enables intelligent and controllable holographic imaging, forming a flexible, efficient, and reconfigurable multifunctional device.

[0053] A reconfigurable multifunctional device capable of achieving independent rotation and synchronized amplitude and phase is also provided, characterized in that the reconfigurable multifunctional device capable of achieving independent rotation and synchronized amplitude and phase is composed of M*N metasurface units with different diode state distributions arranged in a plane at equal intervals and periodically extended.

[0054] The metasurface unit includes a first metal layer, a second metal layer, a third metal layer, and a fourth metal layer, with the three dielectric substrates directly disposed on the metal layers;

[0055] The first metal layer includes two vertically symmetrical circular open rings and two metal strips. Each circular open ring has a variable resistor diode and a switching diode connected in series. The two circular open rings are connected at their tail ends and connected to the metal strips. The third and fourth metal layers are the feed layers for the variable resistor diode and the switching diode, respectively, and their metal structures are rectangular pointing in the y-direction. The second metal layer is a metal ground plane with etched closed circular grooves.

[0056] Furthermore, the dielectric substrate is Rogers 3010 with a dielectric constant of 10.2 and an electrical tangent loss of 0.0022; the active adjustable arc-shaped metal resonator structure, composed of two circular open rings and two metal strips, has a linewidth... =0.4 mm; metal strip length =6.4 mm, the included angle between the two metal strips is 2. , =45°; the radius of the circular open ring r=3.6mm, the arc angle θ=145°; the arc angle formed by the starting end of the circular open ring and the switching diode is =90°; the arc angle formed by the switching diode and the rheostat diode. =30°; Feeder length =15.6 mm, width =0.2 mm; metallized via diameter R=0.25 mm; gap for loading switching diodes. =0.3 mm, gap of the loaded variable resistor diode =0.6 mm; thickness of the first dielectric substrate =4.5 mm, the thickness of the second and third dielectric substrates =0.2mm; period p=16 mm.

[0057] The beneficial effects achieved by this invention are:

[0058] Compared with single-polarization controllable reconfigurable devices, this invention achieves the decoupling of the left-to-right-rotation cross-circular polarization LR and right-to-left-rotation cross-circular polarization RL channels. The output CP wave function under the left-to-right-rotation cross-circular polarization LR and right-to-left-rotation cross-circular polarization RL channels can be designed independently. Under CP wave incident, a single function can be realized. Under LP wave incident, the output CP wave function under the left-to-right-rotation cross-circular polarization LR and right-to-left-rotation cross-circular polarization RL channels can be superimposed and operate in the same frequency band.

[0059] Compared with phase-controlled reconfigurable devices, this invention achieves independent control of phase and amplitude, greatly improving the degree of freedom for controlling the emitted CP wave;

[0060] Compared with traditional passive metasurface multifunctional devices, this invention introduces two types of diodes and uses FPGA to output low-frequency pre-voltage and pre-current to achieve dynamic adjustment of the output CP wave function.

[0061] This invention employs a spin-independent amplitude and phase coherence design method, which involves theoretical guidance including AA phase, electron spin Hall effect, and generalized Snell's law. It breaks through the performance bottlenecks of various single design methods, and the invention has a certain degree of complexity. Attached Figure Description

[0062] Figure 1 This is a functional schematic diagram of a reconfigurable metasurface multifunctional device.

[0063] Figure 2 This is a flowchart illustrating the design process of the rotation-independent amplitude and phase co-tuning method and the reconfigurable multifunctional device of the present invention.

[0064] Figure 3 Metasurface unit in a reconfigurable metasurface multifunctional device. (a) Overall front structure and first-layer active tunable arc-shaped metal resonator structure, (b) Equivalent circuits of the switching diode in "on" and "off" states and the variable resistor diode in different states.

[0065] Figure 4 These are simulation results of metasurface units obtained using CST commercial simulation software. (a) The reflection phase and amplitude of the emitted RCP wave (LCP wave) in the LR (RL) channel when the switching diode is in the "on" and "off" states, with an equivalent resistance of 3 Ω for the variable resistor diode. (b) The reflection phase and amplitude of the emitted RCP wave (LCP wave) in the LR (RL) channel when the switching diode is in the "on" and "off" states, with an equivalent resistance of 100 Ω for the variable resistor diode. (c) The reflection phase and amplitude of the emitted RCP wave (LCP wave) in the LR (RL) channel when the switching diode is in the "on" and "off" states, with an equivalent resistance of 300 Ω for the variable resistor diode.

[0066] Figure 5 The surface-induced cycloid currents under the RL and LR channels are when the (a) RCP wave and (b) LCP wave are incident at 5.35 GHz. At this time, the equivalent resistance of the variable resistor diodes on both sides is 3 Ω and the switching diodes on both sides are in the "on" state.

[0067] Figure 6The results are theoretical calculations of non-uniform four-beam functionality using the commercial software MATLAB. (a) The left and right figures are the phase distribution diagrams required to achieve a specific non-uniform four-beam functionality under the LR and RL channels when LCP and RCP waves are incident at a working frequency of 5.35 GHz, respectively. (b) The left and right figures are the amplitude distribution diagrams required to achieve a specific non-uniform four-beam functionality under the LR and RL channels when LCP and RCP waves are incident at a working frequency of 5.35 GHz, respectively. (c) The left and right figures are the two-dimensional far-field scattering diagrams corresponding to a specific non-uniform four-beam functionality under the LR and RL channels when LCP and RCP waves are incident at a working frequency of 5.35 GHz, respectively.

[0068] Figure 7 The results are theoretical calculations of the non-uniform eight-beam function using the commercial software MATLAB. (a) Mixed amplitude distribution required to achieve a specific non-uniform eight-beam function in the LP channel when the LP wave is incident at a working frequency of 5.35 GHz. (b) Two-dimensional far-field scattering diagram corresponding to the specific non-uniform eight-beam function in the LP channel when the LP wave is incident at a working frequency of 5.35 GHz.

[0069] Figure 8 It is a three-dimensional far-field scattering diagram corresponding to a specific non-uniform four-beam function in the LR channel when LCP wave is incident at a working frequency of 5.35 GHz.

[0070] Figure 9 It is a three-dimensional far-field scattering diagram corresponding to a specific non-uniform eight-beam function under the LP channel when the LP wave is incident at the operating frequency of 5.35 GHz.

[0071] Figure 10 These are the original images selected for imaging. (a) "R" image, (b) "T" image.

[0072] Figure 11 These are theoretical results calculated using the commercial software MATLAB for holographic imaging. (a) The left and right figures are the amplitude distribution diagrams required to achieve a specific holographic imaging function under the LR and RL channels when LCP and RCP waves are incident at a working frequency of 5.35 GHz, respectively. (b) The left and right figures are the phase distribution diagrams required to achieve a specific holographic imaging function under the LR and RL channels when LCP and RCP waves are incident at a working frequency of 5.35 GHz, respectively. (c) The left and right figures are the theoretical calculation results of the reconstructed two-dimensional electric field distribution when LCP and RCP waves are incident at a working frequency of 5.35 GHz, respectively.

[0073] Figure 12The results are three-dimensional simulations of the holographic imaging function obtained using CST commercial simulation software. (a) Two-dimensional electric field distribution diagram of a specific holographic imaging function under the LR channel when LCP wave is incident at a working frequency of 5.35 GHz, (b) Two-dimensional electric field distribution diagram of a specific holographic imaging function under the RL channel when RCP wave is incident at a working frequency of 5.35 GHz. Detailed Implementation

[0074] The technical solution of the present invention will be described in more detail below with reference to the accompanying drawings. The present invention includes, but is not limited to, the following embodiments.

[0075] Example 1

[0076] like Figure 1 As shown, this invention provides a reconfigurable multifunctional device capable of achieving independent amplitude and phase harmonicity. This reconfigurable metasurface multifunctional device is based on an active tunable circular arc metal resonator structure and a reflective isotropic unit constructed from two types of diodes. It is a reconfigurable metasurface multifunctional device capable of independent control in both left-to-right cross-circular polarization (LR) and right-to-left cross-circular polarization (RL) channels. For example... Figure 1 As shown, the invented reconfigurable metasurface multifunctional device achieves one type of non-uniform four-beam or holographic imaging function when a left-hand circularly polarized (LCP) wave is incident; and another type of non-uniform four-beam and holographic imaging function when a right-hand circularly polarized (RCP) wave is incident. When an LP wave is incident, since the LP wave is composed of two circularly polarized wave (CP wave) components with equal amplitude and opposite rotation, the two types of functions can be superimposed, which intuitively demonstrates the superiority of the reconfigurable multifunctional integrated device.

[0077] The reconfigurable metasurface multifunctional device provided by this invention consists of M*N metasurface units of the same size arranged periodically and at equal intervals in a plane. Each metasurface unit is loaded with two types of diodes in different states. To realize the reconfigurable metasurface multifunctional device, the metasurface unit is designed as a multilayer isotropic structure. The metasurface unit is square, and its period (i.e., the length of the metasurface unit) is p. Specifically, the metasurface unit consists of 4 metal structure layers and 3 dielectric substrate layers. The 3 dielectric substrate layers are Rogers 3010 dielectric substrates, and each metal structure layer is printed on a Rogers substrate. On a 3010 dielectric substrate, the metal layers are numbered from top to bottom as the first metal layer, the second metal layer, the third metal layer, and the fourth metal layer. The first metal layer is an active tunable arc-shaped metal resonator structure, which consists of two vertically symmetrical circular open rings and two metal strips. Each circular open ring has a variable resistor diode and a switching diode connected in series. The third and fourth metal layers are the feed layers for the variable resistor diode and the switching diode, respectively, and their metal structures point in the y-direction. The second metal layer is a metal ground plane with etched closed circular grooves. The active tunable arc-shaped metal resonator structure of the first metal layer is connected to the metal ground plane of the second metal layer and the feed layers of the third and fourth metal layers through five metallized vias. The metasurface unit can control the amplitude and phase of the emitted circularly polarized wave (CP wave) with different rotation directions by changing the diode states on different circular open rings, so as to realize holographic imaging or non-uniform multi-beam function under LR or RL channels. Moreover, by simultaneously changing the diode states on the two circular open rings, the superposition of the emitted CP wave function under LR and RL channels can be realized under LP wave incident.

[0078] The equivalent circuits of the switching diode in "on" and "off" states, and the variable resistor diode in different states, are as follows: Figure 3 As shown in (b), when the switching diode is in the "on" state, it is equivalent to a resistor. and inductor When connected in series and in the "off" state, it is equivalent to a capacitor. and inductor In series, the parameters of the lumped elements in the equivalent circuit are: =0.03 pF, =0.03 nH, =7.8 Ω. A variable resistor diode is equivalent to an inductor. and rheostats The series connection of the lumped elements in the equivalent circuit has the following parameters: =0.7 nH, =3~300 Ω. The final unit equivalent circuit is a cascade of two diode equivalent circuits based on the topology.

[0079] The structural parameters of each unit are as follows: The linewidth of the active tunable circular arc metal resonator structure is... The length of the metal strip is The included angle between the two metal strips is 2. The radius of the circular open-loop ring is r, and the arc angle is θ; the arc angle formed by the starting end of the circular open-loop ring and the switching diode is... =90°; the arc angle formed by the switching diode and the rheostat diode is =30°; feeder length is Width is The diameter of the metallized via is R; the gap used to load the switching diode is... The gap between the loaded variable resistor diodes is ; The thickness of the first dielectric substrate. The thicknesses of the second and third dielectric substrates are given; the period is p, which is the length of the metasurface unit.

[0080] The dielectric substrate is Rogers 3010 with a dielectric constant of 10.2 and an electrical tangent loss of 0.0022. The switching diode is M / A-COM MADP-000907-14020x, and the variable resistor diode is NXP BAP70-02.

[0081] Example 2

[0082] Based on the requirements of reconfigurable metasurface multifunctional devices, this invention optimizes the metasurface unit structure design, with the following specific steps:

[0083] Step 1: Introduce elements such as an active tunable arc-shaped metal resonator structure, a switching diode, and a variable resistor diode into the metasurface unit design of the reconfigurable multifunctional device, and construct phase and amplitude independent control modes under the cross-circular polarization LR and cross-circular polarization RL channels respectively.

[0084] For most reconfigurable metasurfaces, it is impossible to achieve independent phase and amplitude control for each channel under the premise of decoupling the cycloid channels. This invention, based on the AA phase and using both switching diodes and variable resistance diodes, achieves independent control of the amplitude and phase of spatial electromagnetic waves under the left-to-right cycloid cross-circular polarization LR and right-to-left cycloid cross-circular polarization RL channels. Specifically, when the incident circularly polarized wave (CP wave) interacts with the metasurface unit in a specific way, the micro-metasurface will change the distribution of the electromagnetic field, and the emitted CP wave will acquire a geometric phase shift. This phase is introduced by the cycloid current induced on the metal surface, i.e., the AA phase. Consistent with antenna theory, the metal size will affect the size of the current transmission path on the metal surface, thereby introducing different phase shifts in the emitted CP wave. At the same time, the size of the surface current will cause the amplitude of the emitted CP wave to change.

[0085] Based on the above theory, the first metal layer of the metasurface unit adopts an active tunable arc-shaped metal resonator structure. This structure introduces independent phase shifts in the LR and RL channels respectively through two vertically symmetrical circular open rings with different rotation directions.

[0086] The specific implementation process is as follows: when the incident CP wave interacts with the unit, the surfaces of the two circular open rings will generate surface induced currents with different rotation directions, thereby generating outgoing CP waves with different rotation directions in space. By changing the path and intensity of the surface induced rotation currents on the two circular open rings, the phase and amplitude of the LCP and RCP waves can be independently controlled respectively.

[0087] Based on this principle, the amplitude and phase of the emitted CP wave can be controlled by changing the intensity and path of the surface current; by simultaneously loading switches and variable resistor diodes on two circular open rings, the emitted CP waves with different spin directions can be spatially controlled by changing the state of the diodes on the left and right circular open rings; from the electron spin Hall effect, it can be known that: ;in, It represents the direction of rotation of the incident CP wave (-1 for LCP wave and 1 for RCP wave). The direction of rotation of the surface-induced rotational current (clockwise rotation represents -1, counterclockwise rotation represents 1). The rotation angle representing the surface-induced rotational current is the arc angle θ in the active adjustable arc-shaped metal resonator structure.

[0088] As can be seen from the above formula, disregarding directionality, the phase of the emitted CP wave is generally twice the surface current rotation angle. The phase of the emitted CP wave can be controlled by changing the surface induced rotation current rotation angle. Therefore, the arc angle formed by the starting end of the circular open ring and the switching diode is set to... =90°. Based on this setting, when using a field-programmable gate array (FPGA) to output the corresponding pre-voltage to control the switching diode in "on" and "off" states, the phase difference of the emitted CP wave between the two states is approximately 180°. This is due to the switching characteristics of the switching diode; the path rotation angle of the induced directional current on the upper surface of the corresponding single circular open ring differs by approximately 90° between the two states. According to Joule's law: ;in, Let I represent heat, R represent current, R represent resistance, and t represent time; it is known that resistance is positively correlated with the electrothermal energy conversion rate. Therefore, to achieve amplitude control of the emitted CP wave, this invention uses a variable resistance diode and also uses a low-frequency pre-current output from an FPGA to change the equivalent resistance of the diode, thereby changing the intensity of the surface-induced cycloidal current on the circular open ring, ultimately achieving amplitude control of the emitted CP wave.

[0089] This invention introduces elements such as an active tunable arc-shaped metal resonator structure, a switching diode, and a variable resistance diode into the metasurface unit design of a reconfigurable multifunctional device, thereby constructing independent phase and amplitude control modes for the emitted CP wave under LR and RL channels, and realizing a new method for rotation-independent amplitude and phase co-modulation and a reconfigurable multifunctional device.

[0090] Step 2: Determine the structural parameters of the adjustable arc-shaped metal resonator, the model parameters of the switching diode and the variable resistor diode according to the predetermined operating frequency band, and calculate the specific functions of the reconfigurable multifunctional device under different rotation polarization wave incident conditions and the corresponding phase and amplitude distribution.

[0091] Specific functions in this embodiment include one-dimensional or two-dimensional deflection function, non-uniform multi-beam function, and holographic imaging function; the above functions are examples, but are not limited to the above functions or combinations.

[0092] For one-dimensional or two-dimensional deflection functions, based on the generalized Snell's theorem, the relationship between the electromagnetic wave reflection phase under a single beam deflection function satisfies:

[0093] (1)

[0094] It is a free-space wave vector. The wavelength corresponding to the operating frequency; It is the reflection phase of the (i, j)th unit; and It represents the distance of the (i, j)th element from the x-axis and y-axis in the Cartesian coordinate system; i is the element in the x-direction of the two-dimensional plane coordinate system, and j is the element in the y-direction of the two-dimensional plane coordinate system. and These are the elevation and azimuth angles of the emitted CP wave, respectively. The initial phase of the metasurface center unit is set to 0° here. Based on the above principle, the metasurface phase distribution can be calculated by setting the deflection direction of a single outgoing beam.

[0095] To achieve spatially non-uniform multi-beam functionality, the normalized reflection coefficient matrix of each outgoing beam is first set. Based on the known complex reflection coefficient matrix, the superposition principle is applied to multiple deflected beams to calculate the final continuous amplitude and phase distribution.

[0096] Let the complex reflection coefficient matrix of the two deflected beams be... and The complex reflection coefficient matrix after superposition is: The expressions and superposition rules of the three are as follows:

[0097] (2)

[0098] (3)

[0099] (4)

[0100] (5)

[0101] Taking a non-uniform four-beam function under LCP wave incidence as an example, the elevation angle, azimuth angle, and normalized reflection amplitude weights of the four beams are first set to (45°, 0°, 1), (30°, 90°, 0.7), (45°, 180°, 1), and (30°, 270°, 0.7), respectively. Then, using the generalized Snell's theorem and the principle of superposition of complex reflection amplitude weights, the continuous phase distribution and amplitude distribution of the desired function can be obtained. Finally, the continuous phase distribution and amplitude distribution obtained above are normalized. Since it is a programmable metasurface, the phase and amplitude also need to be encoded. One-bit phase encoding and two-bit amplitude encoding are used to obtain the final discrete phase distribution and amplitude distribution required.

[0102] Since some values ​​in the amplitude distribution calculated by linear superposition are greater than 1, which does not comply with the requirement that values ​​in the amplitude distribution must be less than or equal to 1, it is necessary to normalize the maximum value of the amplitude distribution.

[0103]

[0104] This represents the amplitude distribution after final normalization required to achieve the third wavenumber deflection function.

[0105] According to electromagnetic wave polarization theory, an LP wave consists of two CP wave components with equal amplitude but opposite directions of rotation. Therefore, to further explore the value of reconfigurable multifunctional devices and improve their functional efficiency, non-uniform multibeam or holographic imaging functions in the LR and RL channels can be set by simultaneously changing the diode states on the two open resonant rings, and the electromagnetic wave functions in the LR and RL channels can be superimposed by using LP wave incident. Taking the non-uniform eight-beam function under LP wave incidence as an example, firstly, the elevation angle, azimuth angle, and normalized reflection amplitude weights of the eight beams are set as (45°, 0°, 1), (30°, 90°, 0.5), (45°, 180°, 1), (30°, 270°, 0.5), (30°, 0°, 1), (45°, 90°, 0.7), (30°, 180°, 1), and (45°, 270°, 0.7), respectively. Then, the first four beams and the last four beams are assigned as two functions to the LR and RL channels, respectively. Finally, the discrete phase distribution and amplitude distribution of the specific function under the two channels can be calculated. The superposition steps of other functions, such as holographic imaging and non-uniform multi-beam functions, are the same as above.

[0106] For holographic imaging, the two-dimensional image being imaged is converted into a two-dimensional numerical matrix of the electric field distribution on the imaging surface.

[0107] Based on the Rayleigh-Sommerfeld diffraction theory, we can obtain the required phase and amplitude distribution of the metasurface using the following formulas:

[0108] (6)

[0109] In the formula and These represent two-dimensional numerical matrices representing the electric field distributions of the holographic surface and the imaging surface, respectively. and k represent the operating wavelength and the wave number in free space, respectively. On the meta-holographic plane ( , , 0) onto the imaging plane ( , The distance of F) The imaging region is defined as follows: Based on the amplitude of the extracted virtual target holographic image, a Fast Fourier Transform is performed on the phase and amplitude distribution of the constructed metasurface. Furthermore, based on the principle of optical path reversibility, the reconstructed image on the imaging plane can also be calculated. The electric field distribution on the surface is expressed by the following formula:

[0110] (7)

[0111] Taking holographic imaging under LCP wave incidence as an example, firstly, the two-dimensional image to be imaged is selected and binarized. Then, based on Rayleigh-Sommerfeld diffraction theory, the continuous phase distribution and amplitude distribution required for metasurface holographic imaging can be calculated using the binarized data matrix of the image. At the same time, the electric field distribution of the reconstructed image on the imaging plane can be calculated theoretically. Finally, the continuous phase distribution and amplitude distribution obtained above are normalized and encoded. One-bit phase encoding and two-bit amplitude encoding are used to obtain the final discrete phase distribution and amplitude distribution. The final required amplitude and phase distribution are then assigned to the left-to-right cross-circular polarization LR channel and the right-to-left cross-circular polarization RL channel, respectively.

[0112] The specific encoding process includes:

[0113] First, the amplitude and phase distributions are normalized to the maximum values ​​of 1 and 360, respectively. Then, the normalized amplitude distribution is encoded using 2 bits according to the following logic: when the amplitude value is greater than or equal to 0 and less than 0.25, it is set to 0.25; when the amplitude value is greater than or equal to 0.25 and less than 0.5, it is set to 0.5; when the amplitude value is greater than or equal to 0.5 and less than 0.75, it is set to 0.75; when the amplitude value is greater than or equal to 0.75 and less than 0.95, it is set to 0.95. Finally, the normalized phase distribution is encoded using 1 bit according to the following logic: when the phase value is greater than or equal to 0° and less than 180°, it is set to 0°; when the phase value is greater than or equal to 180° and less than 360°, it is set to 180°.

[0114] Step 3: Based on the predetermined function and the calculated phase and amplitude distribution, determine the topology of the reconfigurable multifunctional device, that is, the state of the diode on each metasurface unit on the aperture, to realize the reconfigurable multifunctional device.

[0115] First, this invention mainly uses the low-frequency pre-voltage and pre-current output by the FPGA to control the "on" and "off" states of the switching diode and the equivalent resistance of the variable resistor diode, thereby achieving independent control of the phase and amplitude of the emitted electromagnetic wave.

[0116] Therefore, the metal structure of each metasurface unit in the aperture is uniform, that is, M*N metasurface units are periodically extended along the x and y directions. Then, based on the phase and amplitude distribution calculated in step 2, the state distributions of the two diodes corresponding to each phase and amplitude distribution under different CP wave incident conditions are found. Among them, the 180° phase corresponds to the "on" state of the switching diode and is represented by '1', and the 0° phase corresponds to the "off" state of the switching diode and is represented by '0'. Based on the state, the FPGA output pre-voltage is finally determined to be high or low, and it is defined that the switching diode is in the "on" state when the pre-voltage is greater than 1.4V, and in the "off" state otherwise.

[0117] The amplitude encoding is set to four states: 0.95, 0.75, 0.5, and 0.25, each corresponding to an equivalent resistance value. The values ​​are 3Ω, 50Ω, 140Ω, and 300Ω. Based on the equivalent resistance value and the resistance-preamplifier current relationship curve of the variable resistor diode, the required low-frequency preamplifier current for the FPGA output can be calculated, which are 25 mA, 0.7 mA, 0.26 mA, and 0.14 mA, respectively.

[0118] Finally, by using different polarization feed sources to excite metasurface integrated devices, holographic imaging, non-uniform multi-beam function, and superposition of electromagnetic wave functions in LR and RL channels under different combinations of two diode states are achieved when CP wave is incident. Furthermore, by outputting corresponding low-frequency pre-voltage and pre-current through FPGA to control the "on" and "off" states of the switching diodes and the equivalent resistance of the variable resistor diodes, the non-uniform multi-beam can be arbitrarily switched in terms of quantity, direction, and amplitude. It can also realize the intelligent controllability of holographic imaging, thus forming a flexible, efficient, and reconfigurable multifunctional device.

[0119] The optimized structural parameters obtained by the method of this invention are as follows: p = 16 mm. =15.6 mm, =0.3 mm, =0.6 mm, =0.4 mm, =0.2 mm, =6.4 mm, r=3.6mm, θ=145°, =90°, =30°, =45°, R=0.25 mm, =4.5 mm and =0.2 mm; the metal is copper with a thickness of 0.036 mm; the switching diode model is M / A-COM MADP-000907-14020x; the variable resistor diode model is NXP BAP70-02.

[0120] Example 3

[0121] An embodiment is also provided, with the following design specifications: at 5.35 GHz, the metasurface unit can control the amplitude and phase of the emitted CP wave with different rotation directions by changing the diode states on different circular open rings, thereby realizing non-uniform multi-beam or holographic imaging functions under RL or LR channels. Moreover, by simultaneously changing the diode states on two circular open rings, under LP wave incident conditions, arbitrary superposition of non-uniform multi-beam and holographic imaging functions under RL and LR channels can be achieved.

[0122] To achieve Figure 1 The reconfigurable metasurface multifunctional device shown can be implemented in two steps: metasurface unit design and metasurface design. A flowchart of the specific design process is shown below. Figure 2 As shown.

[0123] 1. Metasurface unit design

[0124] The metasurface unit disclosed in this invention is as follows: Figure 3 As shown in (a), the metasurface unit has a period p = 16 mm and consists of 4 metal structure layers and 3 dielectric layers. The 4 metal structure layers are numbered 1, 2, 3, and 4 from top to bottom. The 3 Rogers 3010 dielectric layers separate the 4 metal structure layers. The dielectric constant and tangent loss of the dielectric layers are 10.2 and 0.0022, respectively. The thickness of the first dielectric layer is... =4.5 mm, the thickness of the second and third dielectric substrates is 1.5 mm. =0.2 mm. Feeder length is =15.6 mm, width is 0.2 mm. The diameter of the metallized via is R=0.25 mm; the linewidth of the first layer active tunable arc-shaped metal resonator structure is =0.4 mm, the length of the metal strip is =6.4 mm, the included angle between the two metal strips is 2. =90°, the radius of the circular open ring is r=3.6 mm, and the arc angle is θ=215°; the arc angle formed by the starting end of the circular open ring and the switching diode is =90°; the arc angle formed by the switching diode and the rheostat diode is =30°. The first layer contains two switching diodes and two rheostat diodes, with each switching diode and each rheostat diode forming a combination, divided into two groups, arranged in series on two circular open rings. The switching diode model is M / A-COM MADP-000907-14020x, and the rheostat diode model is NXP BAP70-02. The gap used to load the switching diodes is... =0.3mm, the gap of the loaded variable resistor diode is =0.6 mm. The equivalent circuits of the switching diode in "on" and "off" states, and the variable resistor diode in different states, are as follows: Figure 3 As shown in (b), when the switching diode is in the "on" state, it is equivalent to a resistor. and inductor When connected in series and in the "off" state, it is equivalent to a capacitor. and inductor In series, the parameters of the lumped elements in the equivalent circuit are: =0.03 pF, =0.03 nH, =7.8 Ω. A variable resistor diode is equivalent to an inductor. and rheostats The series connection of the lumped elements in the equivalent circuit has the following parameters: =0.7 nH, =3~300 Ω. The final unit equivalent circuit is a cascade of two diode equivalent circuits based on the topology.

[0125] To verify the phase and amplitude modulation characteristics of the unit cells and the principle of rotational decoupling, full-wave simulations of the metasurface unit cells were performed in CST. For example... Figure 4 As shown in (a), when an LCP wave or an RCP wave (the result is the same after two CP waves are incident) is incident and the equivalent resistance of the variable resistor is 3 Ω, regardless of whether the switching diode is "on" or "off", the electromagnetic wave reflection amplitude weight at a frequency of 5.35 GHz can achieve a value of over 0.9; at the same time, as Figure 4 As shown in (ac), as the equivalent resistance of the variable resistor diode increases, the reflection amplitude weight of the emitted CP wave decreases within the range of 0.25~0.95 at the 5.35 GHz frequency. Simultaneously, the phase difference of the emitted CP wave in both switching diode states remains approximately 180°, satisfying the requirements for amplitude modulation and 1-bit phase encoding. Furthermore, to verify the AA phase and electron rotation Hall effect, the metasurface induced rotational surface current under different rotational CP wave incidences is analyzed. Figure 5(a) It can be seen that when both switching diodes are simultaneously in the "on" state, when an RCP wave is incident on the unit at a frequency of 5.35 GHz, a significant annular surface induced current will appear on the left circular open ring, while no obvious phenomenon will appear on the right circular open ring; correspondingly, from Figure 5 (b) It can be seen that when the LCP wave is incident on the unit at a frequency of 5.35 GHz, an obvious ring surface induced current will appear on the open resonant ring on the right, while there is no obvious phenomenon on the circular open ring on the left. This verifies the correctness of the unit using AA phase to achieve rotational decoupling.

[0126] According to the AA phase principle, under the incidence of CP waves with different rotation directions, the surface of the circular open ring will generate surface rotation-induced currents with different rotation directions, i.e., different directions of electron deflection, thus generating CP waves with different rotation directions in space. Based on this principle, the amplitude and phase of the emitted CP wave can be controlled by changing the intensity and path of the surface current. To verify the AA phase characteristics of the unit, switches and variable resistor diodes were simultaneously loaded on the two circular open rings, and the electron spin Hall effect was used to... It can be seen that, disregarding directionality, the phase of the emitted CP wave is generally twice the surface current rotation angle. The phase of the emitted CP wave can be controlled by changing the surface current rotation angle. Therefore, the arc angle formed by the starting end of the circular open ring and the switching diode is set to... =90°, when using the FPGA output response pre-voltage to control the switching diode to be in the "on" and "off" states, the phase difference of the emitted CP wave in the two states is exactly 180°. Figure 4 (ac) verifies this, satisfying the 1-bit phase encoding requirement; according to Ohm's law It is known that resistance is positively correlated with electrothermal energy conversion efficiency. Using a variable-resistance diode, and employing a low-frequency pre-current output from an FPGA to change the equivalent resistance of the diode, thereby altering the surface current intensity on the circular open ring, ultimately achieving amplitude modulation of the CP wave. Figure 4 (ac) also verifies this, with the electromagnetic wave reflection amplitude weight varying in the range of 0.25 to 0.95.

[0127] As can be seen from the above simulation, by designing different states of the two types of diodes on different circular open rings, the phase and amplitude of the emitted RCP or LCP wave can be independently controlled in the LR or RL channels. At the same time, by using the FPGA to output low-frequency pre-voltage and pre-current, the states of the switching diode and the variable resistor diode can be changed to achieve functional reconfiguration, which lays the foundation for the subsequent realization of reconfigurable multifunctional devices.

[0128] 2. Metasurface Design

[0129] Based on the above metasurface units and electromagnetic properties, this invention discloses a reconfigurable metasurface multifunctional device. The reconfigurability of this metasurface multifunctional device depends on the tunability of two types of diode states; therefore, throughout the entire metasurface, all parameters remain unchanged except for the two types of diode states. Thus, by periodically extending the metasurface units along the x and y directions, a metasurface multifunctional device consisting of 41×41 units is constructed. Next, the phase distribution is calculated for specific non-uniform multibeam or holographic imaging functions, and the corresponding diode states are designed.

[0130] First, a non-uniform four-beam function was designed for LCP and RCP wave incidence. The elevation, azimuth, and normalized reflection amplitude weights of the four reflected beams in the LR channel were set to (45°, 0°, 1), (30°, 90°, 0.7), (45°, 180°, 1), and (30°, 270°, 0.7), respectively; the elevation, azimuth, and normalized reflection amplitude weights of the four reflected beams in the RL channel were set to (30°, 0°, 1), (45°, 90°, 0.5), (30°, 180°, 1), and (45°, 270°, 0.5), respectively. The final calculated phase and amplitude distributions are as follows: Figure 6 As shown in (a) and (b), the phase distribution of the entire metasurface is composed of two phase codes, "0" and "1", while the amplitude distribution is composed of four reflection amplitude weight codes: 0.95, 0.75, 0.5, and 0.25. To verify this, numerical calculations were first performed in MATLAB to obtain the theoretically calculated values ​​of the two-dimensional far-field scattering pattern, as shown below. Figure 6 As shown in (c), the deflection angles and intensity ratios of the four reflected beams match the preset values. Finally, FDTD simulation calculations are performed in CST, using LCP plane waves as incident waves to obtain a three-dimensional far-field scattering map. The final data results are then post-processed to obtain the power ratios between different deflected beams in space, as shown in the figure. Figure 8 As shown, the non-uniform multi-beam function under a single CP wave channel as predetermined by the present invention has been verified.

[0131] Then, holographic imaging functions under LCP and RCP wave incidence were designed. The target image for holographic imaging was set to the character "R" in the LR channel and to the character "T" in the RL channel. The original images are shown below. Figure 10 As shown in (a) and (b), the final calculated amplitude and phase distributions are as follows. Figure 11 As shown in (a) and (b), the phase distribution of the entire metasurface is composed of two phase codes, "0" and "1", while the amplitude distribution is composed of four reflection amplitude weight codes: 0.95, 0.75, 0.5, and 0.25. To verify this, numerical calculations were first performed in MATLAB to obtain the theoretically calculated values ​​of the two-dimensional electric field distribution diagram, as shown below. Figure 11As shown in (c), the theoretical calculation result matches the preset image; finally, FDTD simulation calculations were performed in CST, using LCP and RCP plane waves as incident waves to obtain a two-dimensional electric field distribution diagram, as shown in [image]. Figure 12 As shown in (a) and (b), the holographic imaging function under the predetermined LR and RL channels of the present invention is verified.

[0132] Finally, a non-uniform eight-beam function under LP wave incidence was designed. The elevation, azimuth, and normalized reflection amplitude weights of the eight reflected beams under the LP channel were set to (45°, 0°, 1), (30°, 90°, 0.5), (45°, 180°, 1), (30°, 270°, 0.5), (30°, 0°, 1), (45°, 90°, 0.7), (30°, 180°, 1), and (45°, 270°, 0.7), respectively. The final calculated phase distribution is as follows: Figure 6 As shown in (a), due to the feeding method, when simultaneously controlling the amplitude and phase of the two cross-circularly polarized waves, there is coupling between the states of the variable resistor diodes on both sides. Therefore, it is necessary to calculate the mixed amplitude distribution, such as... Figure 7 As shown in (a). To verify this, numerical calculations were first performed in MATLAB to obtain the theoretically calculated values ​​of the two-dimensional far-field scattering map, as shown in (a). Figure 7 As shown in (b), the deflection angles and intensity ratios of the four reflected beams match the preset values. Finally, FDTD simulation calculations are performed in CST, using LP plane waves as incident waves to obtain a three-dimensional far-field scattering map. The final data results are then post-processed to obtain the power ratios between different deflected beams in space, as shown in Figure (b). Figure 9 As shown, the superposition of non-uniform multi-beam function under LR and RL channels under LP wave incident is verified.

[0133] This invention is not limited to the specific embodiments described above. Those skilled in the art can implement this invention using various other specific embodiments based on the disclosed content of the embodiments and accompanying drawings. Therefore, any design that adopts the design structure and concept of this invention and makes some simple changes or modifications falls within the protection scope of this invention.

Claims

1. A method for achieving amplitude and phase synchronization with independent rotation direction, characterized in that, The method for achieving independent amplitude and phase synchronization in rotation includes the following steps: Step 1: Introduce active tunable arc-shaped metal resonator structure, switching diode, variable resistance diode and other elements into the metasurface unit design of reconfigurable multifunctional device, and construct phase and amplitude independent control modes under the left-to-right circular polarization LR and right-to-left circular polarization RL channels under the same operating frequency band. Step 2: Determine the structural parameters of the adjustable arc-shaped metal resonator, the model parameters of the switching diode and the variable resistor diode according to the predetermined operating frequency band, set the function of the reconfigurable multifunctional device under different cycloid polarization wave incident and calculate the corresponding phase and amplitude distribution. The functions include one-dimensional or two-dimensional deflection function, non-uniform multi-beam function, and holographic imaging function. Step 3: Based on the predetermined function and the calculated phase and amplitude distribution, determine the topology of the reconfigurable multifunctional device, that is, the state of the diode on each metasurface unit on the aperture, to realize the reconfigurable multifunctional device. The reconfigurable multifunctional device is composed of M*N metasurface units with different diode state distributions arranged in a plane with equal spacing and periodic extension. The metasurface unit includes a first metal layer, a second metal layer, a third metal layer, and a fourth metal layer, with the three dielectric substrates directly disposed on the metal layers; The first metal layer includes two vertically symmetrical circular open rings and two metal strips. Each circular open ring has a variable resistor diode and a switching diode connected in series. The two circular open rings are connected at their tail ends and connected to the metal strips. The third and fourth metal layers are the feed layers for the variable resistor diode and the switching diode, respectively, and their metal structures are rectangular pointing in the y-direction. The second metal layer is a metal ground plane with etched closed circular grooves. The metasurface unit controls the amplitude and phase of electromagnetic waves emitted in different directions by changing the state of the diodes on different circular open rings, thereby realizing non-uniform multi-beam or holographic imaging functions in the left-to-right circular polarization (LR) or right-to-left circular polarization (RL) channels. Furthermore, by simultaneously changing the state of the diodes on the two circular open rings, the functions of the two cross-circular polarization channels can be superimposed when the linearly polarized wave is incident.

2. The method for achieving independent amplitude and phase synchronization according to claim 1, characterized in that, In step 2, the one-dimensional or two-dimensional deflection function, based on the generalized Snell's theorem, calculates the metasurface phase distribution. The relationship between the electromagnetic wave reflection phase under a single beam deflection function satisfies: ； It is a free-space wave vector. The wavelength corresponding to the operating frequency; It is the reflection phase of the (i, j)th unit; and It represents the distance of the (i, j)th element from the x-axis and y-axis in the Cartesian coordinate system; i is the element in the x-direction of the two-dimensional plane coordinate system, and j is the element in the y-direction of the two-dimensional plane coordinate system. and These are the elevation and azimuth angles of the emitted circularly polarized wave, respectively. This is the initial phase of the metasurface center unit, set to 0° here.

3. The method for achieving independent amplitude and phase synchronization according to claim 2, characterized in that, In step 2, the non-uniform multi-beam function calculates the final continuous amplitude distribution A and phase distribution by setting the normalized reflection coefficient matrix of each outgoing beam and applying the superposition principle to multiple deflected beams based on the complex reflection coefficient matrix. ; The complex reflection coefficient matrix of the two deflected beams is and The complex reflection coefficient matrix after superposition is: The expressions and superposition rules of the three are as follows: ； ； ； ； in, This represents the amplitude distribution required to achieve the first wavenumber deflection function. This represents the amplitude distribution required to achieve the second wavenumber deflection function. This represents the amplitude distribution required to achieve the third wavenumber deflection function. This represents the phase distribution required to achieve the first wavenumber deflection function. This represents the phase distribution required to achieve the second wavenumber deflection function. This represents the phase distribution required when two wavenumber deflection functions are superimposed. N represents the number of rows of metasurface units in a reconfigurable metasurface multifunctional device, and N represents the number of columns of metasurface units in the reconfigurable metasurface multifunctional device. (n) represents the coordinates of any metasurface unit in a reconfigurable metasurface multifunctional device. Represents the imaginary unit; Since some values ​​in the amplitude distribution calculated by linear superposition are greater than 1, which does not comply with the requirement that values ​​in the amplitude distribution must be less than or equal to 1, it is necessary to normalize the maximum value of the amplitude distribution. ； This represents the amplitude distribution after final normalization required to achieve the third wavenumber deflection function.

4. The method for achieving independent amplitude and phase synchronization according to claim 3, characterized in that, In step 2, the non-uniform multi-beam function also includes a non-uniform four-beam function and a non-uniform eight-beam function. For the aforementioned non-uniform four-beam function, the following steps are included: First, the elevation angle, azimuth angle, and normalized reflection amplitude weights of the four beams are set to (45°, 0°, 1), (30°, 90°, 0.7), (45°, 180°, 1), and (30°, 270°, 0.7), respectively. Secondly, by using the generalized Snell's theorem and the principle of superposition of complex reflection amplitude weights, the continuous phase distribution and amplitude distribution of the desired function can be obtained; Finally, the solved continuous phase and amplitude distributions are normalized, and the normalized phase and amplitude distributions are encoded with 1 bit and 2 bits respectively to obtain the final discrete phase and amplitude distributions.

5. The method for achieving independent amplitude and phase synchronization according to claim 4, characterized in that, In step 2, the non-uniform eight-beam function includes the following steps: First, the elevation angle, azimuth angle, and normalized reflection amplitude weights of the eight beams are set as (45°, 0°, 1), (30°, 90°, 0.5), (45°, 180°, 1), (30°, 270°, 0.5), (30°, 0°, 1), (45°, 90°, 0.7), (30°, 180°, 1), and (45°, 270°, 0.7), respectively. Secondly, the first four beams and the last four beams are assigned as two functions, respectively, to the left-to-right circularly polarized LR and the right-to-left circularly polarized RL channels. Next, the discrete phase distribution and amplitude distribution of the above functions under the two channels were calculated respectively; Finally, the phase and amplitude are encoded using 1 bit of phase encoding and 2 bits of amplitude encoding.

6. The method for achieving independent amplitude and phase synchronization according to claim 1, characterized in that, In step 2, the holographic imaging function first converts the two-dimensional image being imaged into a two-dimensional numerical matrix of the electric field distribution of the imaging surface; The phase and amplitude distribution required to calculate the metasurface: ； In the formula, and Let represent the two-dimensional numerical matrices of the electric field distribution on the holographic surface and the imaging surface, respectively. and k represent the operating wavelength and the wave number in free space, respectively, and n represents the nth unit. On the meta-holographic plane ( , , 0) onto the imaging plane ( , The distance of F) The imaging region is defined as i, where i is the imaginary unit. The electric field distribution of the reconstructed image on the imaging plane is calculated using the Fast Fourier Transform algorithm. Electric field distribution on: ； After obtaining the electric field distribution of the holographic surface, its basic form can be obtained using... This indicates that further solving for the phase components in the electric field is necessary. and amplitude components That is, continuous phase distribution and amplitude distribution. The continuous phase distribution and amplitude distribution are normalized and the phase and amplitude are encoded. 1 bit phase encoding and 2 bit amplitude encoding are used to obtain the final discrete phase distribution and amplitude distribution. The final required amplitude and phase distribution are then assigned to the left-to-right circularly polarized LR and right-to-left circularly polarized RL channels, respectively.

7. The method for achieving independent amplitude and phase synchronization according to any one of claims 4-6, characterized in that, In step 2, the phase distribution and amplitude distribution undergo normalized data processing and encoding, including: First, the amplitude distribution and phase distribution are normalized to the maximum values ​​of 1 and 360, respectively. Secondly, the normalized amplitude distribution is encoded using 2 bits: When the amplitude value is greater than or equal to 0 and less than 0.25, set it to 0.25; when the amplitude value is greater than or equal to 0.25 and less than 0.5, set it to 0.5; when the amplitude value is greater than or equal to 0.5 and less than 0.75, set it to 0.75; when the amplitude value is greater than or equal to 0.75 and less than 0.95, set it to 0.

95. Finally, the normalized phase distribution is encoded using 1 bit: When the phase value is greater than or equal to 0° and less than 180°, set it to 0°; when the phase value is greater than or equal to 180° and less than 360°, set it to 180°.

8. The method for achieving independent amplitude and phase synchronization according to claim 1, characterized in that, Step 3 also includes: First, based on the phase and amplitude distributions, the state distributions of the two diodes corresponding to each phase and amplitude distribution under different CP wave incident conditions are identified. A 180° phase corresponds to the "on" state of the switching diode and is represented by '1', while a 0° phase corresponds to the "off" state of the switching diode and is represented by '0'. Based on these states, the FPGA output preamplifier voltage is ultimately determined to be either high or low. Four states in the amplitude encoding—0.95, 0.75, 0.5, and 0.25—are set, each corresponding to an equivalent resistance value. The values ​​are 3 Ω, 50 Ω, 140 Ω and 300 Ω. Based on the equivalent resistance value and the resistance-preamplifier current relationship curve of the variable resistor diode, the required low-frequency preamplifier current of the FPGA can be deduced, which are 25 mA, 0.7 mA, 0.26 mA and 0.14 mA respectively. Finally, by using different polarization feed sources to excite metasurface integrated devices, holographic imaging and non-uniform multi-beam functionality are achieved under different combinations of two diode states when CP wave incident, as well as the superposition of electromagnetic wave functions under left-hand to right-hand cross-circular polarization LR and right-hand to left-hand cross-circular polarization RL channels when LP wave incident. Furthermore, by outputting corresponding low-frequency pre-voltage and pre-current through FPGA to control the "on" and "off" states of the switching diodes and the equivalent resistance of the variable resistor diodes, the non-uniform multi-beams can be arbitrarily switched in terms of quantity, direction, and amplitude. This also enables intelligent and controllable holographic imaging, forming a flexible, efficient, and reconfigurable multifunctional device.

9. A reconfigurable multifunctional device capable of achieving rotationally independent amplitude and phase co-modulation according to any one of claims 1-8, characterized in that, The reconfigurable multifunctional device capable of achieving independent rotation and synchronized amplitude and phase consists of M*N metasurface units with different diode state distributions arranged in a plane with equal spacing and periodic extension. The metasurface unit includes a first metal layer, a second metal layer, a third metal layer, and a fourth metal layer, with the three dielectric substrates directly disposed on the metal layers; The first metal layer includes two vertically symmetrical circular open rings and two metal strips. Each circular open ring has a variable resistor diode and a switching diode connected in series. The two circular open rings are connected at their tail ends and connected to the metal strips. The third and fourth metal layers are the feed layers for the variable resistor diode and the switching diode, respectively, and their metal structures are rectangular pointing in the y-direction. The second metal layer is a metal ground plane with etched closed circular grooves.

10. The reconfigurable multifunctional device capable of achieving independent amplitude and phase co-orthogonality according to claim 9, characterized in that, The dielectric substrate is Rogers 3010 with a dielectric constant of 10.2 and an electrical tangent loss of 0.0022. The active adjustable arc-shaped metal resonator structure, consisting of two circular open rings and two metal strips, has a linewidth... =0.4 mm; metal strip length =6.4 mm, the included angle between the two metal strips is 2 times. , =45°; the radius of the circular open ring r=3.6mm, the arc angle θ=145°; the arc angle formed by the starting end of the circular open ring and the switching diode is =90°; the arc angle formed by the switching diode and the rheostat diode. =30°; Feeder length =15.6 mm, width =0.2 mm; metallized via diameter R=0.25 mm; gap for loading switching diodes. =0.3 mm, gap of the loaded variable resistor diode =0.6 mm; thickness of the first dielectric substrate =4.5 mm, the thickness of the second and third dielectric substrates =0.2 mm; period p=16 mm.

Images