Method for multi-dimensional joint regulation of electromagnetic wave beams based on anisotropic holographic metasurface

Abstract

This invention discloses a multi-dimensional joint control method for electromagnetic beams based on anisotropic holographic metasurfaces. It aims to address the shortcomings of existing multi-beam multi-dimensional control capabilities and the problems of inter-beam coupling and interference. The method includes: 1) constructing a target field according to the requirements of the actual application scenario, selecting a feed source, and determining its excitation reference field; 2) calculating the metasurface impedance components using tensor holography theory based on the target field and reference field to complete the physical structure design; 3) introducing a fully polarized modulation matrix into the target field expression and adding power allocation coefficients for beams of different polarizations to achieve joint control of arbitrary polarization and different energy ratios; 4) introducing a spatial multiplexing strategy into the beam field to jointly optimize the propagation direction and initial radiation position of different beams; and simultaneously combining polarization isolation and amplitude-phase modulation to achieve stable multi-beam transmission. This invention can effectively improve the anti-interference capability and energy utilization of multi-beam transmission, meeting the requirements of system applications.

Description

Technical Field

[0001] This invention belongs to the field of metasurface electromagnetic control technology, and further relates to electromagnetic wave multidimensional control technology. Specifically, it is a method for multidimensional joint control of electromagnetic beams based on anisotropic holographic metasurfaces, which can be used in scenarios such as energy-carrying communication, wireless energy transmission, and wireless interconnection. Background Technology

[0002] With the continuous development of radio technology, its application fields are becoming increasingly widespread. In the rapid evolution of multi-functional integrated systems such as 5G / 6G communication, Wireless Information and Power Synchronous Transfer (SWIPT), and intelligent sensor networks, the multi-dimensional control capability of electromagnetic waves has become a core element determining system performance. These scenarios not only require precise energy distribution and low-interference multi-beam transmission, but also place stringent demands on the miniaturization and easy integration of devices, urgently requiring a core technology carrier that can comprehensively address these needs. Metasurfaces, as a subwavelength two-dimensional artificial structure, have become a key direction for breaking through the bottlenecks of traditional electromagnetic control technologies due to their flexible control capabilities over the amplitude, phase, and polarization of electromagnetic waves. However, traditional metasurfaces cannot achieve multi-dimensional control through a single device; for example, it is difficult to integrate the control capabilities of different polarizations into a single metasurface, let alone accurately distribute the energy of multiple beams with different polarizations. As an artificial two-dimensional metamaterial, although metasurfaces can control electromagnetic waves through simple structures, they have many limitations in multi-dimensional electromagnetic wave control, multi-beam modulation, precise energy distribution, and functional integration, making it difficult to meet the application requirements of multi-functional systems.

[0003] Currently, Y. Shen, S. Xue, J. Yang, S. Hu, 2021, 6, 2001047 proposed a tensor holographic metasurface that can independently control diffraction-free beams with orthogonal linear polarization and achieve flexible propagation direction control. To theoretically analyze the proposed structure, a superposition theory was established, using tensor units to modulate the surface impedance. Furthermore, a polynomial formula was derived to represent the equivalent surface impedance of the tensor unit, thereby generating the pattern of the target radiation field. However, this method cannot achieve full polarization multiplexing or precise energy allocation between multi-polarization multi-beams, nor does it propose an interference suppression scheme. HX Liu, YC Li, FJ Cheng, X. Wang, MYChang, H. Xue, S. Zhang, JQ Han, GX Li, L. Li, TJ Cui, 2024, 34, 2307806. From an energy perspective, a holographic tensor metasurface was proposed to achieve flexible control of polarization and energy distribution for simultaneous power and information transmission. A highly isolated dual-polarized receiving metasurface was also proposed to achieve simultaneous power and information reception. Based on these two metasurfaces, a novel wireless information and power transmission system was established, which transmits microwave power and information signals by flexibly adjusting electromagnetic waves with different polarizations. The proposed holographic tensor metasurface can generate diffraction-free Bessel beams with two polarizations to maintain high power transmission efficiency in environments with obstacles. However, this method does not integrate the ability to combine linear and circular polarization into a single metasurface, making it difficult to achieve power allocation for more beams and suppress inter-beam interference. Y. Shen, S. Xue, G. Dong, J. Yang, S. Hu, Adv. Opt. Mater. 2021, 9, 2101340. A method for generating multimode multibeams using a planar single-layer metasurface with shared aperture was proposed. The basic principle is to achieve the multiplexing of tensor holographic metasurfaces by superimposing modulated impedance surfaces. This multiplexed metasurface generates individual beams through the interference pattern formed between the target radiation field and the reference current. To verify the proposed method, a multiplexed metasurface structure capable of simultaneously generating two different beams was proposed. These two beams have different mode characteristics, including different beam types, different operating frequencies, different polarization methods, and different depths of focus, enabling circular polarization control. However, this method still needs improvement in terms of multi-beam performance enhancement and precise energy allocation; it cannot accurately allocate power to multiple corresponding beams and does not perform inter-beam interference suppression.

[0004] Existing solutions are unable to achieve joint control of linear and circular polarization on a single device, and are even less able to achieve precise allocation of multi-beam power based on polarization dimension control. They cannot meet the core requirements of multi-beam non-interference and differentiated power allocation in multi-functional integrated systems, thus restricting the improvement of system performance in related scenarios. Summary of the Invention

[0005] The purpose of this invention is to address the shortcomings of existing technologies by proposing a multi-dimensional joint control method for electromagnetic beams based on anisotropic holographic metasurfaces. This method aims to solve the problems of insufficient multi-beam, multi-dimensional control capabilities and inter-beam coupling interference in existing technologies. This invention introduces tensor holographic units with high degrees of freedom and anisotropy, and proposes a target field superposition theory that combines full polarization and precise multi-beam power allocation. A full polarization modulation matrix is ​​introduced into the target field to further modify the weighting coefficients of the multi-beam power, establishing a beam control scheme that covers various polarization states and can precisely allocate power to multiple corresponding beams. Simultaneously, a multi-beam interference suppression scheme based on spatial multiplexing is proposed and deeply integrated with the full polarization multiplexing scheme and the precise multi-beam power allocation scheme. This scheme controls interference from both the propagation direction and initial position: firstly, it combines orthogonal polarization control with amplitude and phase control, causing multiple beams to point in different directions in the spatial dimension, reducing beam cross-polarization interference while improving aperture utilization and beam coverage; secondly, it uses spatial coordinate design to translate and separate the initial beam positions, further reducing near-field coupling and interference. This invention can promote the development of 5G / 6G, multi-functional integrated systems for synchronous wireless information and energy transmission, and chip wireless interconnection, and facilitate the large-scale application of special beams in practical scenarios and the industrial application of metasurfaces.

[0006] To achieve the above objectives, the technical solution of the present invention includes the following:

[0007] (1) Based on the requirements of the actual application scenario, set the number of electromagnetic beams, working frequency band, beam type, polarization state, propagation direction and energy distribution ratio to be realized, and construct the target field function that meets the performance index; at the same time, in combination with the application platform and feeding architecture of the metasurface, select the appropriate feed type, and determine the reference field distribution excited by the feed on the aperture surface of the metasurface through electromagnetic simulation or theoretical calculation.

[0008] (2) Based on the constructed target field and reference field, the field quantity mapping relationship is established using tensor holography theory. The surface impedance tensor components required at each unit position of the metasurface are calculated. Then, combined with the tensor unit equivalent impedance database established in advance through full-wave simulation, the theoretical impedance requirements at each position are mapped to the actual unit size parameters and rotation angles through the minimum error matching algorithm, thus completing the physical structure design of the metasurface.

[0009] (3) By introducing a fully polarized modulation matrix into the target field expression, the polarization state of each beam in the formula can be controlled; at the same time, power allocation coefficients for circular polarization and linear polarization are added to satisfy the total energy constraint. Under the premise of [previous conditions], power is allocated to each beam according to a preset ratio, and [this is] introduced before the circular polarization component. The normalized power coefficient enables joint control of arbitrary polarization and different energy ratios to meet the needs of full polarization multiplexing and precise multi-beam energy allocation.

[0010] (4) By introducing a spatial multiplexing strategy into the field expression of the beam, the propagation direction and initial radiation position of different beams are jointly optimized and designed so that each beam can achieve directional separation and position separation in the spatial dimension; at the same time, by combining polarization isolation and amplitude-phase modulation technology, the electromagnetic coupling and energy interference between multiple beams are reduced, and finally, stable transmission of multiple beams is achieved.

[0011] Compared with the prior art, the present invention has the following advantages:

[0012] First, this invention innovatively proposes a multidimensional electromagnetic wave control scheme based on anisotropic holographic metasurfaces. It integrates the theory of fully polarized modulation matrix and power-distribution target field superposition, and combines it with spatial multiplexing interference suppression strategy to achieve coordinated and precise control of electromagnetic waves in polarization, energy distribution and spatial distribution dimensions. This scheme can achieve the technical effects of multi-beam fully polarized multiplexing, precise energy distribution on demand and low interference transmission, effectively solving the problems of single electromagnetic wave control dimension and insufficient energy distribution accuracy in the existing technology.

[0013] Secondly, this invention combines the target field superposition theory of full polarization and multi-beam power precision allocation. By introducing a full polarization modulation matrix into the target field and correcting the multi-beam power weighting coefficient, a multi-beam power precision allocation and control system covering the full polarization state is constructed. At the same time, it integrates a spatial multiplexing multi-beam interference suppression scheme to achieve multi-beam interference suppression from both the propagation direction and initial position dimensions. Compared with the existing technology, this significantly improves the anti-interference capability and energy utilization rate of multi-beam transmission.

[0014] Third, this invention, for the first time, utilizes anisotropic holographic metasurfaces to achieve high-performance multi-beams with precise energy distribution and full polarization multiplexing capabilities. Based on full polarization multiplexing schemes, target field superposition theory, and interference suppression schemes, electromagnetic energy can be distributed to different polarizations, directions, and positions in a specific ratio, and multi-beam multi-dimensional control can be achieved through simple devices. This control method is compatible with various beam types such as high-gain beams, Bessel beams, focused beams, and Airy beams, and can further achieve multiplexing or energy enhancement functions by combining anisotropic metasurfaces with multiple feed sources. The method and devices proposed in this invention are characterized by simple structure and high functional integration, and can be well adapted to the application requirements of SWIPT systems and other integrated systems. Attached Figure Description

[0015] Figure 1 This is a flowchart illustrating the overall implementation of the method of the present invention;

[0016] Figure 2 The anisotropic tensor holographic metasurface unit structure and its equivalent impedance characteristic diagram in this invention, wherein (a) is a geometric diagram of the tensor unit and (b) is a distribution diagram of the effective impedance database;

[0017] Figure 3 The diagram shows the control results of the two-dimensional Airy beam under different polarization states in this invention. (a) is the amplitude distribution diagram required to generate the two-dimensional Airy beam, (b) is the phase distribution diagram required to generate the two-dimensional Airy beam, and (c), (d), (e), and (f) are sub-diagrams that include the distribution diagram of the tensor surface impedance components (Zxx, Zxy, Zyy) on the left and the simulation diagram of the electric field (E-field) distribution on the right ((c) and (d) are linear polarization, including linear polarization in the x and y directions; (e) and (f) are circular polarization, including the distribution of left-hand circular polarization (LHCP) and right-hand circular polarization (RHCP) components).

[0018] Figure 4 The simulation verification diagram of the precise allocation of Airy beam polarization energy in this invention includes three sub-graphs (a), (b), and (c), which correspond to the control effects of the x and y polarization energy allocation ratios of 2:1, 4:1, and 10:1, respectively. Each sub-graph consists of two parts: the distribution of tensor surface impedance components (Zxx, Zxy, Zyy) and the corresponding x-polarization and y-polarization electric field distributions.

[0019] Figure 5 The diagrams show the verification of multi-beam spatial multiplexing and energy distribution control in this invention. (a) and (b) are the amplitude and phase distribution diagrams required to generate x-polarized and y-polarized Airy beams on the positive half-axis of the xoz plane, respectively. (c) and (d) are the tensor surface impedance component distributions (Zxx, Zxy, Zyy) and the corresponding x-polarized and y-polarized electric field distributions required when the energy distribution of the two beams is 4:1 and 1:1, respectively.

[0020] Figure 6 The diagram shows the joint control results of multi-beams with different polarizations under spatial separation conditions. It shows the impedance component distribution and the corresponding electric field intensity distribution when a left-hand circularly polarized beam on the positive x-axis and a y-polarized beam on the positive y-axis are generated simultaneously with an energy ratio of 1:1.

[0021] Figure 7The diagram shows the electric field distribution results under multi-beam and multi-energy ratio allocation, where (a), (b), and (c) represent the Airy beam electric field distribution diagrams with different linear polarizations and directions when the energy allocation is 1:2:1, 1:4:1, and 1:10:1, respectively. Detailed Implementation

[0022] The present invention will now be further described with reference to the accompanying drawings.

[0023] Example 1: Refer to Appendix Figure 1 The present invention proposes a method for multidimensional joint control of electromagnetic beams based on anisotropic holographic metasurfaces, which specifically includes the following steps:

[0024] Step 1) Based on the requirements of the actual application scenario, set the number of electromagnetic beams, operating frequency band, beam type, polarization state, propagation direction and energy distribution ratio to be realized, and construct the target field function that meets the performance index; at the same time, in combination with the application platform and feeding architecture of the metasurface, select the appropriate feed type, and determine the reference field distribution excited by the feed on the aperture surface of the metasurface through electromagnetic simulation or theoretical calculation.

[0025] In this embodiment, the feed source is preferably a monopole, and the surface wave excited by it is used as the reference field. The target field is a multi-beam electromagnetic field with a specified polarization state and energy ratio. The multi-beam can be various types of beams such as Airy beams, focused beams, Bessel beams, and high-gain beams.

[0026] Step 2) Based on the constructed target field and reference field, establish the field quantity mapping relationship using tensor holography theory, and calculate the required surface impedance tensor components at each unit location of the metasurface, including... , and Then, combining the tensor element equivalent impedance database pre-established through full-wave simulation, a minimum error matching algorithm is used to map the theoretical impedance requirements at each location to the actual element size parameters and rotation angles, thus completing the physical structure design of the metasurface. In this embodiment, the tensor element equivalent impedance database mentioned in this step is used to characterize the mapping relationship between the element size parameters and the equivalent impedance, as well as the mapping relationship between the rotation angle and the equivalent impedance; during the matching process, it is ensured that the error between the required impedance component at each location and the element's equivalent impedance does not exceed a preset threshold.

[0027] Step 3) By introducing a fully polarized modulation matrix into the target field expression, the polarization state of each beam in the formula can be controlled; at the same time, power allocation coefficients for circular and linear polarization are added to satisfy the total energy constraint. Under the premise of [previous conditions], power is allocated to each beam according to a preset ratio, and [this is] introduced before the circular polarization component. The normalized power coefficient enables joint control of arbitrary polarization and different energy ratios to meet the needs of full polarization multiplexing and precise multi-beam energy allocation.

[0028] In this embodiment, the above-mentioned fully polarized modulation matrix is ​​used to characterize the polarization state of electromagnetic waves, including linear polarization, left-hand circular polarization, and right-hand circular polarization; the power allocation coefficient is a non-negative real number, used to control the proportion of each beam in the total energy, so as to achieve precise energy allocation on demand.

[0029] The above-mentioned full polarization modulation is implemented in the following way:

[0030] Assume the first The polarization matrix that the beam needs to be modulated is: ,in polarization, The matrix representations of polarization, left-hand circularly polarized (LHCP), and right-hand circularly polarized (PHCP) are as follows:

[0031] ;

[0032] When only different linear polarizations or different circular polarizations are modulated. The modulus values ​​remain consistent; if synchronous modulation of linear polarization and circular polarization is required to achieve full polarization multiplexing, then the coefficients before circular polarization are divided by a normalization process. To ensure that it is consistent with the linear polarization magnitude.

[0033] In this embodiment, the joint control of arbitrary polarization and different energy ratios is achieved in the following way to simultaneously meet the requirements of full polarization multiplexing and precise multi-beam energy allocation:

[0034] Assumption The energy ratio of each beam is And satisfy , Given the total energy of the system, the power distribution of the target field is calculated using the following formula:

[0035] ;

[0036] in, For the first The expression for beam waves, Represents the imaginary unit; introduced before circular polarization The power coefficient enables a fully polarized control and energy distribution scheme.

[0037] Step 4) By introducing a spatial multiplexing strategy into the field expression of the beam, the propagation direction and initial radiation position of different beams are jointly optimized and designed to achieve directional and positional separation of each beam in the spatial dimension; at the same time, by combining polarization isolation and amplitude-phase modulation technology, the electromagnetic coupling and energy interference between multiple beams are reduced, and finally stable transmission of multiple beams is achieved.

[0038] In this embodiment, the spatial multiplexing strategy includes setting the propagation direction of different beams to different deflection angles and setting the initial position of each beam to a spatially non-overlapping region; the polarization isolation includes making adjacent beams adopt orthogonal polarization state; the amplitude and phase modulation is to determine the amplitude and phase distribution at each position on the metasurface based on the final state of the target field, which is ultimately mapped to the impedance component distribution at each position through the target field expression.

[0039] Example 2: This example provides an electromagnetic beam multidimensional joint control device, a computer-readable storage medium, and an electronic device based on anisotropic holographic metasurfaces to implement the control method described in Example 1.

[0040] The device described in this embodiment specifically includes: a field construction module, an impedance calculation and element matching module, a multi-dimensional control module, an interference suppression module, and a multi-feed module. The field construction module is used to set the target field based on the required number of electromagnetic beams, operating frequency band, beam type, polarization state, propagation direction, and energy distribution requirements, and to select the feed type to determine the reference field for excitation. The impedance calculation and element matching module is used to calculate the required surface impedance components at each location of the metasurface based on the target field and reference field using tensor holography theory, and to match the size parameters and rotation angles of the elements at each location using a tensor element equivalent impedance database to complete the physical structure design of the metasurface. The multi-dimensional control module is used to construct a target field expression containing a fully polarized modulation matrix for multiple beams, and to introduce a power distribution coefficient to achieve joint control of different polarizations and energy ratios. The interference suppression module is used to achieve spatial separation of multiple beams through a spatial multiplexing strategy, and to reduce coupling and interference between multiple beams by combining polarization isolation. The multi-feed module is used to combine with anisotropic metasurfaces to achieve multi-beam multiplexing or energy enhancement functions.

[0041] The aforementioned computer-readable storage medium stores a computer program thereon, which, when executed by a processor, implements the steps of the electromagnetic beam multidimensional joint control method based on anisotropic holographic metasurfaces in Embodiment 1.

[0042] The aforementioned electronic device includes: a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, it implements the steps of the electromagnetic beam multidimensional joint control method based on anisotropic holographic metasurfaces in Embodiment 1.

[0043] Example 3: The overall implementation steps of the electromagnetic beam multidimensional joint control method provided in this example are the same as in Example 1. Now, in conjunction with the appendix... Figure 1-6 The implementation process of this invention is further described in detail with specific examples, including parameter settings:

[0044] This invention employs anisotropic holographic metasurface units and, based on the design logic of holographic metasurfaces, achieves precise integrated control of electromagnetic beams in dimensions such as polarization, energy ratio, quantity, and spatial distribution. Simultaneously, a spatial diversity strategy suppresses near-field coupling interference between multiple beams, ensuring that each beam performs its function without interference. The solution is compatible with various beam types, including high-gain beams, Airy beams, Bessel beams, and focused beams (in this embodiment, the more difficult-to-implement Airy beam is preferred as an example to demonstrate the method's universality). The reference field can be flexibly selected from monopoles, rectangular waveguides, etc., depending on the application scenario (in this embodiment, a monopole is preferred as an example to improve integration). Finally, through a single low-profile, low-cost device, it achieves comprehensive performance in multi-beam full polarization multiplexing, arbitrary energy distribution, and low-interference transmission. The overall implementation process is as follows: Figure 1 As shown.

[0045] In the design of holographic metasurfaces, the target field and reference field are first clearly defined. In this invention, the target field is the electromagnetic beam to be realized, and the reference field is the field corresponding to the feed source that excites the target field. This invention uses a monopole as the feed source, which excites surface waves. As a reference field, and the target field This refers to beams with arbitrary polarization states and power levels obtained using the proposed method. Based on and The tensor surface impedance components of the holographic metasurface are calculated as follows:

[0046] ;

[0047] in This represents the average real part of the surface impedance. Represents modulation depth. † and ¬ denote the outer product and conjugate transpose, respectively. Using Figure 2 As shown in (a), an array of tensor holographic cells can form a holographic metasurface. The desired target field can be achieved by adjusting the size and rotation angle of each cell at different positions on the metasurface. The equivalent impedance dataset of the tensor cells can be extracted using simulation software. Figure 2 The dataset corresponding to unit (a) in the example is as follows: Figure 2 As shown in (b) above. Based on this, the surface impedance components required at different locations on the metasurface can be calculated using the above formula from the determined target field and reference field, and the obtained surface impedance matching diagram can be used to... Figure 2 The equivalent impedance dataset described in (b) is used to determine the semi-major axis of tensor cells at different locations on the metasurface. short half shaft and rotation angle The parameters are set to achieve the desired target field, i.e., various electromagnetic beams.

[0048] This invention provides a new approach to multidimensional manipulation and interference suppression of the target field and corresponding beam, which will be described in further detail below:

[0049] (I) Full Polarization Regulation

[0050] When constructing a metasurface using tensor units, the required surface impedance at different locations on the metasurface can be determined by the desired target field, and the state of each tensor unit can be further matched using a database. To achieve full polarization control, it is necessary to target the first... Beamwave modulation of its polarization matrix ,in polarization, The matrices corresponding to polarization, left-hand circular polarization (LHCP), and right-hand circular polarization (PHCP) can be represented as follows:

[0051] ;

[0052] When only different linear polarizations or different circular polarizations are modulated. The modulus values ​​must remain consistent. If synchronous modulation of linear and circular polarization is required to achieve full polarization multiplexing, since circular polarization corresponds to... Modulus is Its coefficient needs to be divided by Only in this way can the power be equal to that of the linear polarization form, and at this time, the magnitude of the polarization matrix is... The processing can be considered as part of the power factor.

[0053] (ii) Precise energy allocation for multi-beam multi-polarization

[0054] Based on the achievement of full polarization control, this invention further proposes a multi-beam target field superposition method based on power allocation, which is used to achieve precise control of the energy ratio between multi-beams with different polarizations.

[0055] Compared to the addition principle used in traditional holographic metasurfaces (for... Individual energy beams used Different coefficients are used, so a multi-beam target field superposition method based on power allocation is adopted, which integrates the coefficients from the power perspective and the coefficients derived from the full polarization matrix. Therefore, this method can improve the accuracy of energy allocation and is further applicable to beam scenarios with full polarization control and different energy allocations. Assume... The energy ratio of each beam is : :…: :…: and order The target field can then be modified as follows:

[0056] ;

[0057] in For the first The expression for beam waves, The imaginary unit is introduced before circular polarization. The power coefficient is high, and a full polarization control and energy distribution scheme are achieved simultaneously.

[0058] To verify this, beams with different polarization states were first implemented. Taking the Airy beam as an example, this means... Write the expression for the Airy beam; if you need to generate other beams, simply replace it with the expression for those beams. Figure 3 This paper demonstrates the amplitude and phase distributions required for a two-dimensional Airy beam, as well as the impedance component distributions of various holographic metasurfaces corresponding to different polarizations. Although the required amplitude and phase distributions are the same, the surface impedance component distributions differ for different polarizations, reflecting the characteristics of anisotropic holographic metasurfaces in fully polarized modulation. For linearly polarized Airy beams, the impedance components corresponding to orthogonal polarization do not require modulation; however, for circularly polarized beams, all surface impedance components require co-modulation. Figure 3 As can be seen, in the main polarization direction, the beam energy is concentrated on the curved trajectory, maintaining good diffraction-free and self-bending characteristics, while the energy occupied by cross-polarization is minimal. Therefore, the anisotropic holographic metasurface realizes full polarization modulation of the beam.

[0059] After completing full polarization modulation, the energy distribution of beams in different polarization states can be controlled based on the above theory. Figure 4 The surface impedance component distributions corresponding to energy ratios of 2:1, 4:1, and 10:1 are shown to illustrate their differences. When generating two orthogonal linearly polarized beams simultaneously, it is necessary to synchronously modulate the three components of the surface impedance (…). , , ).along with The gradual increase in polarization beam energy corresponds to the impedance component of the polarization. The modulation range gradually expands, while the orthogonal Polarization corresponds to impedance components ( The modulation range of ) approaches 0. The components always need to be modulated.

[0060] Compared to existing research that struggles to achieve arbitrary energy allocation across different beams, the proposed method can precisely distribute the desired energy to beams with different polarizations, especially when the energy ratio is not 1:0 or 0:1. As the ratio increases, the electric field of the x-polarized beam is enhanced, while the electric field of the y-polarized beam weakens accordingly. This indicates that the power allocation-based multi-beam target field superposition method can be combined with a fully polarized multiplexing scheme and is applicable to arbitrary energy allocation scenarios.

[0061] (III) Multi-beam interference suppression

[0062] To address the problem of coupling and mutual interference between multiple beams, this invention proposes a multi-dimensional interference suppression scheme based on spatial multiplexing. First, it combines orthogonal polarization control with amplitude and phase control, so that multiple beams point in different directions in the spatial dimension, thereby reducing beam cross-polarization interference while improving aperture utilization and beam coverage. Second, it uses spatial coordinate design to translate and separate the initial position of the beams, further reducing near-field coupling and interference.

[0063] Beams with different polarizations or energy ratios along axis, The beam is shifted a preset distance along different coordinate axes, such as the x-axis, and the beam deflection is completed. Near-field coupling can be reduced by physically separating the initial position from the propagation direction. Figure 5 As shown. Figure 5 In the diagram, (a)-(b) represent the amplitude and phase distributions. Figure 5 (c)-(d) in the figures represent the corresponding electric field distributions. It can be seen that the multi-beam performance remains good despite different polarizations and powers. The adjustment of their initial positions (each beam was shifted 50mm towards the positive x-axis and y-axis respectively) and directions (the beams are located in the xoz and yoz planes respectively) further ensures that the beams are not affected by other beams, confirming the effectiveness of interference suppression. Thus, multi-dimensional control forms a multiple interference suppression mechanism through polarization isolation, position separation, and direction separation, ensuring low-interference transmission of multi-beams.

[0064] To further verify the effectiveness, this embodiment also provides beam simulation results with a 1:1 ratio of left-hand circular polarization to y-polarization after adjusting the initial position and beam direction, as shown below. Figure 6 As shown; and the Airy beam electric field distributions with different linear polarizations, directions, and initial positions when the energy ratios are 1:2:1, 1:4:1, and 1:10:1, respectively, as shown. Figure 7 As shown, it can be seen that full polarization, energy ratio, and spatial position changes can all be effectively achieved.

[0065] The effects of the present invention will be further explained below with reference to simulation experiments.

[0066] 1. Simulation conditions:

[0067] The simulation experiments of this invention were conducted in a high-performance computer hardware environment and an electromagnetic full-wave simulation (HFSS) software environment.

[0068] 2. Simulation content:

[0069] Using a pre-established tensor unit equivalent impedance database, the designed anisotropic holographic metasurface was modeled and calculated using electromagnetic full-wave simulation. The effectiveness of the proposed method in full polarization control, multi-beam energy distribution, and interference suppression was verified. Specifically, as follows... Figures 3 to 7 As shown.

[0070] 3. Simulation results:

[0071] Figure 3 The diagram shows the control results of the two-dimensional Airy beam under different polarization states. It can be seen that the generated beams under x-polarization, y-polarization and left and right circular polarization conditions all have good diffraction-free and self-bending characteristics. The energy is concentrated in the main polarization direction and the cross-polarization component is small, which verifies the effectiveness of the method proposed in this invention in full polarization control.

[0072] Figure 4 The figure shows the results of multi-beam modulation under different energy allocation ratios. It can be seen that when the energy allocation ratios are 2:1, 4:1 and 10:1, the electric field intensity of each beam shows significant differences with the change of energy ratio. The electric field in the target polarization direction gradually increases, while the orthogonal polarization component gradually weakens, which verifies that the proposed method can achieve accurate allocation of multi-beam energy.

[0073] Figure 5 The figure shows the results of multi-beam spatial separation, polarization control, and energy allocation control. It can be seen that different polarization beams are effectively separated in space (both in terms of initial position and propagation direction). Under different energy ratios (4:1 and 1:1), each beam can still maintain good propagation characteristics and has little interference with each other, indicating that the proposed method can achieve stable multi-beam transmission under spatial separation conditions.

[0074] Figure 6 The diagram shows the spatial separation and control results of multi-beams with different polarizations. It can be seen that when left-handed circularly polarized beams and linearly polarized beams are generated simultaneously with an energy ratio of 1:1, each beam propagates in different directions, and the electric field distribution is clear and does not interfere with each other. This further verifies the effectiveness of the present invention in the joint control of multi-polarization and multi-beams and interference suppression.

[0075] Figure 7The figure shows the electric field distribution results under multiple beams and multiple energy ratio allocations. It can be seen that under different energy allocation ratios such as 1:2:1, 1:4:1 and 1:10:1, the electric field intensity of each beam shows good controllability as the ratio changes. At the same time, beams with different polarizations and directions can be stably generated, which further verifies the applicability and robustness of the method of the present invention in complex multi-beam scenarios.

[0076] The above simulation analysis proves the correctness and effectiveness of the method proposed in this invention.

[0077] The parts of this invention not described in detail are common knowledge to those skilled in the art.

[0078] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Obviously, those skilled in the art, after understanding the content and principles of the present invention, may make various modifications and changes in form and detail without departing from the principles and structure of the present invention. These modifications include: replacing or adjusting the metasurface unit structure, geometric dimensions, and material parameters; changing the feed type and its arrangement; adjusting the target electromagnetic beam type (such as Bessel beams, focused beams, high-gain beams, etc.), polarization form, and energy distribution ratio; and equivalent replacements of the modeling methods, simulation techniques, and parameter settings used in the implementation. However, these modifications and changes based on the ideas of the present invention are still within the scope of protection of the claims of the present invention.

Claims

1. A method for multidimensional joint control of electromagnetic beams based on anisotropic holographic metasurfaces, characterized in that, Includes the following steps: (1) Based on the requirements of the actual application scenario, set the number of electromagnetic beams, working frequency band, beam type, polarization state, propagation direction and energy distribution ratio to be realized, and construct the target field function that meets the performance index; at the same time, in combination with the application platform and feeding architecture of the metasurface, select the appropriate feed type, and determine the reference field distribution excited by the feed on the aperture surface of the metasurface through electromagnetic simulation or theoretical calculation. (2) Based on the constructed target field and reference field, the field quantity mapping relationship is established using tensor holography theory. The surface impedance tensor components required at each unit position of the metasurface are calculated. Then, combined with the tensor unit equivalent impedance database established in advance through full-wave simulation, the theoretical impedance requirements at each position are mapped to the actual unit size parameters and rotation angles through the minimum error matching algorithm, thus completing the physical structure design of the metasurface. (3) By introducing a fully polarized modulation matrix into the target field expression, the polarization state of each beam in the formula can be controlled; at the same time, power allocation coefficients for circular polarization and linear polarization are added to satisfy the total energy constraint. Under the premise of [previous conditions], power is allocated to each beam according to a preset ratio, and [this is] introduced before the circular polarization component. The normalized power coefficient enables joint control of arbitrary polarization and different energy ratios to meet the needs of full polarization multiplexing and precise multi-beam energy allocation. (4) By introducing a spatial multiplexing strategy into the field expression of the beam, the propagation direction and initial radiation position of different beams are jointly optimized and designed so that each beam can achieve directional separation and position separation in the spatial dimension; at the same time, by combining polarization isolation and amplitude-phase modulation technology, the electromagnetic coupling and energy interference between multiple beams are reduced, and finally, stable transmission of multiple beams is achieved.

2. The method according to claim 1, characterized in that: The feed source in step (1) uses a monopole and uses the surface wave excited by it as the reference field. The target field is a multi-beam electromagnetic field with a specified polarization state and energy ratio. The multi-beam includes at least an Airy beam, a focusing beam, a Bessel beam, and a high-gain beam.

3. The method according to claim 1, characterized in that: The surface impedance component in step (2) includes , , The tensor unit equivalent impedance database is used to characterize the mapping relationship between the unit's size parameters and rotation angle and the equivalent impedance. During the matching process, it is ensured that the error between the required impedance component at each position and the unit's equivalent impedance does not exceed a preset threshold.

4. The method according to claim 1, characterized in that: The fully polarized modulation matrix in step (3) is used to characterize the polarization state of electromagnetic waves, including linear polarization, left-hand circular polarization, and right-hand circular polarization; the power allocation coefficient is a non-negative real number used to control the proportion of each beam in the total energy, so as to achieve precise energy allocation on demand.

5. The method according to claim 4, characterized in that: The full polarization modulation described in step (3) is implemented as follows: Assume the first The polarization matrix that the beam needs to be modulated is: ,in polarization, The matrix representations of polarization, left-hand circularly polarized (LHCP), and right-hand circularly polarized (PHCP) are as follows: ； When only different linear polarizations or different circular polarizations are modulated. The modulus values ​​remain consistent; if synchronous modulation of linear polarization and circular polarization is required to achieve full polarization multiplexing, then the coefficients before circular polarization are divided by a normalization process. To ensure that it is consistent with the linear polarization magnitude.

6. The method according to claim 5, characterized in that: The arbitrary polarization and different energy ratios described in step (3) are jointly controlled through the following methods to simultaneously meet the requirements of full polarization multiplexing and precise multi-beam energy allocation: Assumption The energy ratio of each beam is And satisfy , Given the total energy of the system, the power distribution of the target field is calculated using the following formula: ； in, For the first The expression for beam waves, Represents the imaginary unit; introduced before circular polarization The power coefficient enables a fully polarized control and energy distribution scheme.

7. The method according to claim 1, characterized in that: The spatial multiplexing strategy in step (4) includes setting the propagation direction of different beams to different deflection angles and setting the initial position of each beam to a region that does not overlap in space; the polarization isolation includes making adjacent beams adopt orthogonal polarization state; the amplitude and phase modulation is to determine the amplitude and phase distribution at each position on the metasurface based on the final state of the target field, which is ultimately mapped to the impedance component distribution at each position through the target field expression.

8. A multi-dimensional joint control device for electromagnetic beams based on anisotropic holographic metasurfaces, characterized in that, include: The module includes a field construction module, an impedance solution and element matching module, a multi-dimensional control module, an interference suppression module, and a multi-feed module. The field construction module is used to set the target field according to the required number of electromagnetic beams, operating frequency band, beam type, polarization state, propagation direction and energy distribution requirements, and select the feed type to determine the reference field it excites. The impedance calculation and element matching module is used to calculate the required surface impedance components at each position of the metasurface based on the target field and the reference field using tensor holography theory, and to match the size parameters and rotation angles of the elements at each position with the tensor element equivalent impedance database to complete the design of the metasurface physical structure. The multidimensional control module is used to construct a target field expression containing a fully polarized modulation matrix for multiple beams, and to introduce a power allocation coefficient to achieve joint control of different polarizations and different energy ratios. The interference suppression module is used to achieve spatial separation of multiple beams through a spatial multiplexing strategy, and to reduce coupling and interference between multiple beams by combining polarization isolation. The multi-feed module is used to combine with anisotropic metasurfaces to achieve multi-beam multiplexing or energy enhancement functions.

9. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by the processor, it implements the steps of the electromagnetic beam multidimensional joint control method based on anisotropic holographic metasurface as described in any one of claims 1 to 7.

10. An electronic device, characterized in that: The method includes a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, it implements the steps of the electromagnetic beam multidimensional joint control method based on anisotropic holographic metasurfaces as described in any one of claims 1 to 7.

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