A dual-frequency non-diffracting multi-beam antenna based on a super surface and a design method thereof

Abstract

The application provides a kind of based on super surface dual-frequency non-diffractive multi-beam antenna and design method, it is related to electromagnetic field, antenna includes unit structure, unit structure includes first layer metal patch, second layer metal patch and third layer metal patch;First layer metal patch is sensitive to high-frequency electromagnetic wave response, and third layer metal patch is sensitive to low-frequency electromagnetic wave response.Through the parameter of first and second layer patch is respectively conditioned, the array reflection phase of array unit at two operating frequencies is realized independent control, and then the non-diffractive beam array reflection phase distribution is realized according to actual needs, realizes dual-frequency non-diffractive focusing effect, according to generalized Snell law, further realizes for non-diffractive beam arbitrary angle deflection, finally the superposition of multiple single-beam array reflection phase distribution can be realized multi-beam non-diffractive.The application has the advantages of small array, wide focusing range, flexible beam direction control and simple manufacturing.

Description

Technical Field

[0001] This invention belongs to the field of electromagnetics, relates to microwave radio frequency technology, and particularly relates to a dual-frequency diffraction-free multi-beam antenna based on metasurface and its design method. Background Technology

[0002] Currently, electromagnetic waves transmit information and energy during propagation. When electromagnetic waves are used for wireless communication, we focus on the communication information they carry; when used for wireless power transmission, we focus on the energy they carry. Whether using electromagnetic waves for wireless communication or wireless power transmission, we desire a high electromagnetic power density at the receiving antenna after the electromagnetic wave is emitted. For communication systems, a higher electromagnetic power density means it's easier to reach the receiver's minimum receiving sensitivity; for electromagnetic power transmission, a higher receiving electromagnetic power density means that more electromagnetic energy can be received within the same receiving area.

[0003] Link transmission efficiency is a perennial topic in wireless communication and wireless power transmission. Whether using a single antenna or an antenna array, the transmitting device for electromagnetic waves cannot suppress the fact that, due to the diffraction characteristics of electromagnetic waves, the cross-section perpendicular to the propagation axis increases with increasing transmission distance. In other words, the coverage area of ​​an electromagnetic wave expands with increasing transmission distance. When the propagation process of electromagnetic waves is calculated using the Gaussian model, the Rayleigh distance is an important parameter used to describe the rate of increase in the cross-section during propagation. The increase in the cross-section of the electromagnetic wave inevitably leads to a decrease in its electromagnetic power density. This reduces transmission efficiency for point-to-point high-speed communication or microwave wireless power transmission, making it unsuitable for long-distance power transmission. Therefore, we need a beam that maintains a stable electromagnetic power density along the propagation path for wireless power transmission—a diffraction-free beam.

[0004] Currently known diffraction-free beam designs are available in wide-band or large-depth-of-field directions, and there are no metasurface designs with dual-frequency diffraction-free multi-beams.

[0005] Therefore, how to provide a dual-frequency diffraction-free multi-beam antenna based on metasurfaces and its design method has become a technical problem that urgently needs to be solved in this field. Summary of the Invention

[0006] The purpose of this invention is to provide a dual-frequency diffraction-free multi-beam antenna based on metasurfaces and its design method.

[0007] According to a first aspect of the present invention, a dual-frequency diffraction-free multi-beam antenna based on a metasurface is provided, the antenna comprising: a unit cell structure,

[0008] The unit structure includes a first metal patch, a second metal patch, and a third metal patch;

[0009] The first layer of metal patch is a double E-type metal patch, including a first E-type metal patch and a first E-type metal patch; the openings of the first E-type metal patch and the first E-type metal patch are arranged inwards and correspondingly, and the gap between the openings is a first distance p1w;

[0010] The second layer of metal patch is a triple-ring patch, including a first ring patch, a second ring patch and a third ring patch; the diameters of the three rings gradually increase and they are nested together on the same surface;

[0011] The third layer of metal patch is a double-bent metal patch. The openings of the first double-bent metal patch and the first double-bent metal patch are arranged inwards and correspondingly, and the gap between the openings is the second distance p2w.

[0012] The first metal patch is sensitive to high-frequency electromagnetic waves, while the third metal patch is sensitive to low-frequency electromagnetic waves.

[0013] Preferably, the first metal patch, the second metal patch, and the third metal patch are respectively disposed on the printed circuit board dielectric material layer.

[0014] Preferably, the third metal patch is an E-shaped double-horizontal structure metal patch with an added horizontal line in the E-shaped structure.

[0015] Preferably, the upper surface of the unit structure is a metasurface.

[0016] Preferably, the dual-frequency diffraction-free multi-beam antenna is an array unit comprising multiple unit structures.

[0017] According to a second aspect of the present invention, a design method for a metasurface-based dual-frequency diffraction-free multi-beam antenna is provided, the method being applied to the metasurface-based dual-frequency diffraction-free multi-beam antenna described in any one of the first aspects of the present invention, the method comprising:

[0018] Step S1: Obtain the parameters of the dual-frequency diffraction-free multi-beam antenna. The parameters include a first distance p1w and a second distance p2w. By changing the two parameters, the first distance p1w and the second distance p2w, any reflection phase in the range of 0° to 300° at the 2.4GHz and 5.6GHz frequencies can be obtained.

[0019] Step S2: The phase distribution of the array reflection generated by the non-diffraction focused beam can be calculated using the phase distribution formula of the non-diffraction focused beam.

[0020] Step S3: The array reflection phase distribution corresponding to any deflection angle beam can be obtained by calculation using the generalized Snell's law of refraction.

[0021] Step S4: By superimposing the array reflection phase distributions calculated in steps S2 and S3, the array reflection phase distribution of a single non-diffraction beam can be obtained, and the array reflection phase distribution of a multi-beam beam can be obtained, satisfying the condition formula.

[0022] Step S5: Utilize the condition formula that the reflection phase distribution of the multi-beam array satisfies the condition formula, and then design the unit structure at different coordinates based on the relationship between the reflection phase obtained in step S1 and the two parameters of the first distance p1w and the second distance p2w, and finally obtain the required array unit structure and obtain the dual-frequency diffraction-free multi-beam antenna.

[0023] Preferably, in step S2, the phase distribution formula of the non-diffraction focused beam is used: The phase distribution of array reflections that generate a diffraction-free focused beam can be calculated. Where k0 is the wave number, the surface of the array element can be equivalent to a two-dimensional plane xoy, x and y are the coordinates of the element on the xoy plane, and β is half of the design angle of the array element's equivalent pyramidal lens.

[0024] Preferably, in step S3, the array reflection phase distribution corresponding to any deflection angle beam can be obtained by calculation using the generalized Snell's law of refraction. Where k0 is the wave number, x and y are the coordinates of the array element on the array surface (xoy), and θ1 and θ2 are the deflection angles of the beam in the x and y directions, respectively.

[0025] Preferably, by superimposing the array reflection phase distributions calculated in steps S2 and S3, the array reflection phase distribution for a single non-diffraction beam can be obtained:

[0026]

[0027] The required array reflection phase distribution is obtained based on the focusing range and deflection angle requirements. Then, the array reflection phase distributions of the pre-generated multiple beams are calculated, and the vector sum of the multiple beams is calculated using the principle of electric field superposition, as shown in the following formula:

[0028]

[0029] Where E(x,y) represents the electric field at coordinates (x,y) on the hypersurface, and A(x,y) is the magnitude at that point. The phase of the electric field at that point is the amplitude and phase that the beam emitted by the feed needs to be adjusted to after passing through the metasurface.

[0030] Preferably, the phase distribution of the final generated multi-beam array reflection satisfies: Based on the relationship between the reflection phase and the two parameters p1w and p2w obtained in step S1, the unit structure at different coordinates is designed, and the required array unit is finally obtained.

[0031] As can be seen from the above scheme, the embodiments of the present invention provide a dual-frequency diffraction-free multi-beam antenna based on metasurface and a design method thereof, which has the following beneficial effects:

[0032] Utilizing Bessel beam-focusing theory for diffraction-free beams, the aforementioned array unit structure is designed, comprising three metal patch layers and three printed circuit board dielectric material layers. The top metal patch layer is a double-E type, the middle layer is a triple-ring patch, and the bottom layer is a double-bent metal patch. The parameters of the top double-E type metal patch are sensitive to high-frequency electromagnetic wave responses, while the parameters of the bottom double-bent metal patch are sensitive to low-frequency electromagnetic wave responses. The unit structure itself does not need to be changed; only the unit scaling ratio needs adjustment. Compared to many arrays that require changes to the unit structure, this design is highly advantageous for overall array construction, significantly simplifying the array structure. The small spacing between units effectively reduces the array size for a given number of array elements. Therefore, by separately adjusting the parameters of these two patch layers, the array reflection phase of the array units at two operating frequencies can be independently controlled, thereby achieving a diffraction-free beam array reflection phase distribution according to actual needs and realizing a dual-frequency diffraction-free focusing effect. Attached Figure Description

[0033] Figure 1 This is a three-dimensional structural schematic diagram of a metasurface-based dual-frequency diffraction-free multi-beam antenna according to an embodiment.

[0034] Figure 2 This is a front view of a metasurface-based dual-frequency diffraction-free multibeam antenna according to an embodiment.

[0035] Figure 3 This is a schematic diagram of the first layer metal patch structure in a dual-frequency diffraction-free multi-beam antenna based on a metasurface according to an embodiment.

[0036] Figure 4 This is a schematic diagram of the second metal patch structure in a metasurface-based dual-frequency diffraction-free multibeam antenna according to an embodiment.

[0037] Figure 5 This is a schematic diagram of the third layer metal patch structure in a dual-frequency diffraction-free multibeam antenna based on a metasurface according to an embodiment.

[0038] Figure 6 This is a flowchart illustrating a design method for a metasurface-based dual-frequency diffraction-free multibeam antenna according to an embodiment.

[0039] Figure 7 The flowchart illustrates the calculation process of a design method for a metasurface-based dual-frequency diffraction-free multi-beam antenna according to an embodiment.

[0040] Figure 8 The graph shows the transformation of the reflection phase of the unit cell with respect to dimensions p1w and p2w.

[0041] Figure 9 Design a schematic diagram for the experiment;

[0042] Figure 10 This is a schematic diagram of beam focusing without diffraction.

[0043] Figure 11 Diagram of a dual-frequency, diffraction-free, multi-beam array structure;

[0044] Figure 12 This is a dual-beam non-diffraction focusing pattern.

[0045] Explanation of reference numerals in the attached figures:

[0046] 100 - Unit structure, 1 - First layer metal patch, 11 - First E-type metal patch, 12 - First E-type metal patch, 2 - Second layer metal patch, 21 - First ring patch, 22 - Second ring patch, 23 - Third ring patch, 3 - Third layer metal patch, 31 - First double-bent metal patch, 32 - First E-type metal patch. Detailed Implementation

[0047] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of the embodiments of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0048] This application addresses the technical problem of the lack of miniaturized, one-to-many, high-density multiplexing transmitter arrays in current microwave wireless power transmission systems. Utilizing the Bessel beam-focusing theory without diffraction beams, a method is designed as follows... Figure 2The array unit structure shown comprises three metal patch layers and three printed circuit board dielectric material layers. The top metal patch layer is a double-E type, the middle metal patch layer is a triple-ring patch, and the bottom metal patch is a double-bent metal patch. The parameters of the top double-E type metal patch are sensitive to high-frequency electromagnetic wave response, while the parameters of the bottom double-bent metal patch are sensitive to low-frequency electromagnetic wave response. Therefore, by separately controlling the parameters of these two patch layers, the array reflection phase of the array unit at two operating frequencies can be independently controlled. This allows for the realization of a diffraction-free beam array reflection phase distribution according to actual needs, achieving a dual-frequency diffraction-free focusing effect. Based on the generalized Snell's law, arbitrary angle deflection of the diffraction-free beam can be further achieved. Finally, by superimposing the reflection phase distributions of multiple single-beam arrays, multi-beam diffraction-free beams can be realized. This design has advantages such as small array size, wide focusing range, flexible beam direction control, and simple manufacturing, and is of great significance for the further promotion and application of microwave wireless power transmission.

[0049] Example 1:

[0050] According to a first aspect of the invention, such as Figure 1 and Figure 2 As shown, a dual-frequency diffraction-free multi-beam antenna based on a metasurface is provided, comprising: an array of unit structures 100.

[0051] The unit structure 100 includes a first layer of metal patch 1, a second layer of metal patch 2, and a third layer of metal patch 3;

[0052] like Figure 3 As shown, the first layer of metal patch 1 is a double E-type metal patch, including a first E-type metal patch 11 and a first E-type metal patch 12; the openings of the first E-type metal patch 11 and the first E-type metal patch 12 are arranged inwards and correspondingly, and the gap between the two openings is a first distance p1w;

[0053] like Figure 4 As shown, the second layer metal patch 2 is a triple ring patch, including a first ring patch 21, a second ring patch 22 and a third ring patch 23; the diameters of the three rings gradually increase and they are nested together on the same surface;

[0054] like Figure 5 As shown, the third layer metal patch 3 is an E-shaped double-horizontal structure metal patch with an added horizontal line in the E-shaped structure. The third layer metal patch 3 is a double-bent metal patch, and the openings of the first double-bent metal patch 31 and the second double-bent metal patch 32 are arranged inwards correspondingly, with the gap between the two openings being the second distance p2w;

[0055] The first metal patch 1 is sensitive to high-frequency electromagnetic waves, and the third metal patch 3 is sensitive to low-frequency electromagnetic waves.

[0056] The first metal patch 1, the second metal patch 2, and the third metal patch 3 are respectively disposed on the printed circuit board dielectric material layer. Each patch is disposed on one printed circuit board dielectric material layer.

[0057] The upper surface of the unit structure 100 is a metasurface, and the dual-frequency diffraction-free multi-beam antenna is an array unit consisting of multiple unit structures 100.

[0058] According to a second aspect of the present invention, a design method for a metasurface-based dual-frequency diffraction-free multi-beam antenna is provided, comprising the metasurface-based dual-frequency diffraction-free multi-beam antenna as described in any one of the embodiments in the first embodiment, wherein the parameters include a first distance p1w and a second distance p2w, and by changing the two parameters, the first distance p1w and the second distance p2w respectively, any reflection phase in the range of 0° to 300° at the 2.4 GHz and 5.6 GHz frequencies can be obtained.

[0059] Utilizing Bessel beam-focusing theory for diffraction-free beams, the aforementioned array unit structure is designed, comprising three metal patch layers and three printed circuit board dielectric material layers. The top metal patch layer is a double-E type, the middle layer is a triple-ring patch, and the bottom layer is a double-bent metal patch. The parameters of the top double-E type metal patch are sensitive to high-frequency electromagnetic wave responses, while the parameters of the bottom double-bent metal patch are sensitive to low-frequency electromagnetic wave responses. The unit structure itself does not need to be changed; only the unit scaling ratio needs adjustment. Compared to many arrays that require changes to the unit structure, this design is highly advantageous for overall array construction, significantly simplifying the array structure. The small spacing between units effectively reduces the array size for a given number of array elements. Therefore, by separately adjusting the parameters of these two patch layers, the array reflection phase of the array units at two operating frequencies can be independently controlled, thereby achieving a diffraction-free beam array reflection phase distribution according to actual needs and realizing a dual-frequency diffraction-free focusing effect.

[0060] Example 2

[0061] A second aspect of the present invention provides a design method for a dual-frequency diffraction-free multi-beam antenna based on a metasurface, the method being applied to the aforementioned dual-frequency diffraction-free multi-beam antenna, the method comprising:

[0062] Step S1: Obtain the parameters of the dual-frequency diffraction-free multi-beam antenna. The parameters include a first distance p1w and a second distance p2w. By changing the two parameters, the first distance p1w and the second distance p2w, any reflection phase in the range of 0° to 300° at the 2.4GHz and 5.6GHz frequencies can be obtained.

[0063] Step S2: The phase distribution of the array reflection generated by the non-diffraction focused beam can be calculated using the phase distribution formula of the non-diffraction focused beam.

[0064] In step S2, the phase distribution formula for a non-diffraction focused beam is used: The phase distribution of array reflections that generate a diffraction-free focused beam can be calculated. Where k0 is the wave number, the surface of the array element can be equivalent to a two-dimensional plane xoy, x and y are the coordinates of the element on the xoy plane, and β is half of the design angle of the array element's equivalent pyramidal lens.

[0065] Step S3: The array reflection phase distribution corresponding to any deflection angle beam can be obtained by calculation using the generalized Snell's law of refraction.

[0066] In step S3, the array reflection phase distribution corresponding to any deflection angle beam can be obtained by calculation using the generalized Snell's law of refraction. Where k0 is the wave number, x and y are the coordinates of the array element on the array surface (xoy), and θ1 and θ2 are the deflection angles of the beam in the x and y directions, respectively.

[0067] Step S4: By superimposing the array reflection phase distributions calculated in steps S2 and S3, the array reflection phase distribution for a single non-diffraction beam can be obtained, such as... Figure 10 As shown, the phase distribution of the multi-beam array reflection satisfies the condition formula.

[0068] By superimposing the array reflection phase distributions calculated in steps S2 and S3, the array reflection phase distribution for a single non-diffraction beam can be obtained:

[0069]

[0070] The required array reflection phase distribution is obtained based on the focusing range and deflection angle requirements. Then, the array reflection phase distributions of the pre-generated multiple beams are calculated, and the vector sum of the multiple beams is calculated using the principle of electric field superposition, as shown in the following formula:

[0071]

[0072] Where E(x,y) represents the electric field at coordinates (x,y) on the hypersurface, and A(x,y) is the magnitude at that point. The phase of the electric field at that point is the amplitude and phase that the beam emitted by the feed needs to be adjusted to after passing through the metasurface.

[0073] Step S5: Utilize the condition formula that the reflection phase distribution of the multi-beam array satisfies the condition formula, and then design the unit structure at different coordinates based on the relationship between the reflection phase obtained in step S1 and the two parameters of the first distance p1w and the second distance p2w, and finally obtain the required array unit structure and obtain the dual-frequency diffraction-free multi-beam antenna.

[0074] Since the design assumes a uniform energy distribution, only the phase needs to be considered. The resulting multi-beam array reflection phase distribution satisfies: Based on the relationship between the reflection phase obtained in step S1 and the two parameters of the first distance p1w and the second distance p2w, the unit structure at different coordinates is designed, and the required array unit is finally obtained.

[0075] Example 3

[0076] This embodiment adopts the design method of a dual-frequency diffraction-free multi-beam antenna based on metasurfaces provided in Embodiment 2, and is implemented using Ansoft's commercial electromagnetic simulation software HFSS (High Frequency Structure Simulator) in the following steps:

[0077] Step S1: Obtain the parameters of the dual-frequency diffraction-free multi-beam antenna. The parameters include a first distance p1w and a second distance p2w. By changing the two parameters, the first distance p1w and the second distance p2w, any reflection phase in the range of 0° to 300° at the 2.4GHz and 5.6GHz frequencies can be obtained.

[0078] A dual-frequency reflection unit structure is designed using HFSS, as shown in Example 1 and... Figure 2 As shown, its frequencies are 5.6GHz and 2.4GHz, commonly used in wireless power transmission (the substrate material is curable acrylate sink with a dielectric constant of 2.8 and a loss tangent of 0.012), giving it good reflection efficiency; adjusting the unit ensures that changing the unit's scaling (by adjusting the p1w and p2w parameters) can cover a phase range of approximately 300°, thus obtaining the correspondence between different phases and unit scaling, as shown... Figure 3 As shown; the unit structure of this application has the following advantages:

[0079] First, the unit structure does not need to be changed; only the unit scaling ratio needs to be adjusted. Compared with many arrays that require changes to the unit structure, this is very beneficial for the overall array construction and greatly simplifies the array structure difficulty.

[0080] Second, the small spacing between elements effectively reduces the array size when the number of array elements is fixed.

[0081] Step S2: The phase distribution of the array reflection generated by the non-diffraction focused beam can be calculated using the phase distribution formula of the non-diffraction focused beam.

[0082] In step S2, the phase distribution formula for a non-diffraction focused beam is used: The phase distribution of array reflections that generate a diffraction-free focused beam can be calculated. Where k0 is the wave number, the surface of the array element can be equivalent to a two-dimensional plane xoy, x and y are the coordinates of the element on the xoy plane, and β is half of the design angle of the array element's equivalent pyramidal lens.

[0083] In a specific embodiment, a feed horn with a suitable frequency band and polarization is found. The position of the horn is determined based on its 10dB power angle. Finally, both feed horns are placed on the z-axis of the metasurface's central axis. Figure 9 As shown, the distances of the two feed horns from the upper surface of the supersurface are 358mm and 333mm, respectively.

[0084] Step S3: The array reflection phase distribution corresponding to any deflection angle beam can be obtained by calculation using the generalized Snell's law of refraction.

[0085] In step S3, the array reflection phase distribution corresponding to any deflection angle beam can be obtained by calculation using the generalized Snell's law of refraction. Where k0 is the wave number, x and y are the coordinates of the array element on the array surface (xoy), and θ1 and θ2 are the deflection angles of the beam in the x and y directions, respectively.

[0086] Step S4: By superimposing the array reflection phase distributions calculated in steps S2 and S3, the array reflection phase distribution of a single non-diffraction beam can be obtained, and the array reflection phase distribution of a multi-beam beam can be obtained, satisfying the condition formula.

[0087] By superimposing the array reflection phase distributions calculated in steps S2 and S3, the array reflection phase distribution for a single non-diffraction beam can be obtained:

[0088]

[0089] The required array reflection phase distribution is obtained based on the focusing range and deflection angle requirements. Then, the array reflection phase distributions of the pre-generated multiple beams are calculated, and the vector sum of the multiple beams is calculated using the principle of electric field superposition, as shown in the following formula:

[0090]

[0091] Where E(x,y) represents the electric field at coordinates (x,y) on the hypersurface, and A(x,y) is the magnitude at that point. The phase of the electric field at that point is the amplitude and phase that the beam emitted by the feed needs to be adjusted to after passing through the metasurface.

[0092] Step S5: Utilizing the condition formula that the reflection phase distribution of the multi-beam array satisfies the condition, and based on the relationship between the reflection phase obtained in Step S1 and the two parameters p1w and p2w, design the unit structure at different coordinates, ultimately obtaining the required array unit structure and obtaining a dual-frequency diffraction-free multi-beam antenna, such as... Figure 11 As shown.

[0093] Since the design assumes a uniform energy distribution, only the phase needs to be considered. The resulting multi-beam array reflection phase distribution satisfies: Based on the relationship between the reflection phase obtained in step S1 and the two parameters of the first distance p1w and the second distance p2w, the unit structure at different coordinates is designed, and the required array unit is finally obtained.

[0094] In a specific embodiment, the overall simulation experimental setup is as follows: Figure 9 As shown, the geometric center of the upper surface of the metasurface is taken as the origin, the plane containing the metasurface is taken as the xoy plane, and the axis perpendicular to the metasurface is taken as the Z-axis. The geometric centers of the starting positions of the two feed horns are both set on the Z-axis, and their phase center coordinates are set as (0, 0, z). f Let the coordinates of each reflecting element be (x, y, 0). According to (4-11), the generated k-th non-diffraction beam... The phase at each position of the metasurface unit is:

[0095]

[0096] According to the principle of superposition of electric fields, the electric field distribution expression of the pre-generated multiple beams can be expressed as:

[0097]

[0098] Here, E(x,y) represents the electric field at coordinates (x,y) on the hypersurface, and A(x,y) is the magnitude at that point. Let A be the phase corresponding to the electric field at that location. Here, we discuss the case of simple equal energy distribution, so here A... k Since (x, y) are uniform constant values, the phase distribution on the metasurface to be designed is as follows:

[0099]

[0100] Finally, the above describes the case where the feed source is a plane wave. The experiment used a feed horn, whose beam can be considered a spherical wave. The metasurface needs to compensate for the spherical wave to convert it into a plane wave. The feed horn requires phase compensation. satisfy:

[0101]

[0102] The final compensated phase at various locations on the metasurface satisfy:

[0103]

[0104] This application designs to generate two beams at two different frequency points. The beams generated at 2.4 GHz are: (a) 2.4 GHz: Beam 1: β = 15°, θ1 = 45°, θ2 = 0°; Beam 2: β = 15°, θ1 = -45°, θ2 = 0°; 5.6 GHz: Beam 3: β = 15°, θ1 = 0°, θ2 = 45°; Beam 4: β = 15°, θ1 = 0°, θ2 = -45°. Figure 2 The elements in the array form a 20*20 metasurface array, theoretically with a diffraction-free distance of 970 mm. Actual simulation distances at 2.4 GHz and 5.6 GHz are 950 mm and 1030 mm, respectively. Figure 12 As shown.

[0105] like Figure 6 As shown, the energy is approximately in the Z range. max The concentration is highest at 2 / 2, which is basically consistent with the theory. Its advantage is that, compared to point focusing, the simulated focusing range in this application is prismatic, effectively transmitting energy throughout the entire focusing area. The focusing range is dramatically expanded, unlike point focusing which is limited to a very finite point range by the Rayleigh distance constraint of the Gaussian beam. Furthermore, compared to traditional single-frequency non-diffraction beams, this experiment can better cope with various complex environments in wireless power transmission systems, exhibiting strong anti-interference capabilities. The multi-beam design is geared towards one-to-many power transmission scenarios in wireless power transmission, solving the problem that most past designs based on a single feeder charging a single receiver were inefficient for the entire charging system.

[0106] Experimental results show that:

[0107] from Figure 8 As can be seen, when the p1w transformation range is [4, 14], the phase change range is [100°, -200°], and the phase coverage is close to 300°. When the p2w transformation range is [15, 26], the phase change range is [-3°, -280°], and the phase coverage is close to 280°. This basically meets our phase gradient requirements. Through optimization, we can basically achieve any phase required for diffraction-free focusing. 2) From Figure 6As can be seen, the two beams generated at 2.4 GHz have a relatively ideal focusing effect in the xoz plane, with the deflection angle exactly matching the preset value. The actual focusing distance is almost identical to the theoretical distance (970 mm). The two beams generated at 5.6 GHz also have an ideal focusing effect in the yoz plane, with the deflection angle matching the preset value and the focusing distance greater than the theoretical focusing distance. Furthermore, it can be observed that the energy distribution exhibits a conical waveform distribution in the Z... max The beams are most concentrated at point / 2, confirming that they are indeed diffraction-free beams. Experiments have shown that this design can precisely control the deflection angles of multiple beams, and all can achieve the preset maximum diffraction-free distance. The generated multiple beams have equal energy distribution, consistent with the preset value. Subsequently, the energy distribution of multiple beams can be arbitrarily proportional by adjusting the amplitude of the electromagnetic waves through the unit.

[0108] In summary, this application utilizes a size control unit to adjust the reflection phase, while maintaining the overall unit structure. The reflection phase can be adjusted simply by changing the unit scaling ratio, resulting in a relatively simple overall design. It employs diffraction-free theory to achieve beam focusing. With a fixed array size, the focusing range can be effectively controlled by adjusting the control values, far exceeding point focusing and meeting the long-distance requirements for wireless power transmission. Dual operating frequencies allow the beam to achieve diffraction-free beams at 2.4GHz and 5.6GHz, adapting to various wireless power transmission environments. Multiple beams better adapt to one-to-many wireless power transmission scenarios, and subsequent amplitude modulation allows for more flexible beam energy allocation, improving wireless power transmission efficiency.

[0109] The above are preferred embodiments of the present invention. It should be noted that, for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A dual-frequency diffraction-free multi-beam antenna based on a metasurface, characterized in that, The antenna includes: a unit structure, The unit structure includes a first metal patch, a second metal patch, and a third metal patch; The first layer of metal patch is a double E-type metal patch, including a first E-type metal patch and a first E-type metal patch; the openings of the first E-type metal patch and the first E-type metal patch are arranged inwards and correspondingly, and the gap between the openings is a first distance p1w; The second layer of metal patch is a triple ring patch, including a first ring patch, a second ring patch and a third ring patch; the diameters of the first ring patch, the second ring patch and the third ring patch gradually increase, and they are nested together on the same surface; The third layer of metal patch is a double-bent metal patch. The openings of the first double-bent metal patch and the first double-bent metal patch are arranged inwards and correspondingly, and the gap between the openings is the second distance p2w. The first metal patch is sensitive to high-frequency electromagnetic waves, and the third metal patch is sensitive to low-frequency electromagnetic waves. The first metal patch, the second metal patch, and the third metal patch are respectively disposed on the printed circuit board dielectric material layer; The third layer of metal patch is an E-shaped double-horizontal structure metal patch with an added horizontal line in the E-shaped structure; The upper surface of the unit structure is a metasurface; The dual-frequency diffraction-free multi-beam antenna is an array unit consisting of multiple unit structures.

2. A design method for a dual-frequency diffraction-free multi-beam antenna based on metasurfaces, wherein the method is applied to the dual-frequency diffraction-free multi-beam antenna of claim 1, characterized in that, The method includes: Step S1: Obtain the parameters of the dual-frequency diffraction-free multi-beam antenna, including a first distance p1w and a second distance p2w. By changing the first distance p1w and the second distance p2w respectively, any reflection phase in the range of 0° to 300° at the 2.4GHz and 5.6GHz frequencies can be obtained. Step S2: Calculate the phase distribution of the array reflection generated by the diffraction-free focused beam using the phase distribution formula for the diffraction-free focused beam. Step S3: Calculate the array reflection phase distribution corresponding to any deflection angle beam using the generalized Snell's law of refraction; Step S4: By superimposing the array reflection phase distributions calculated in steps S2 and S3, the array reflection phase distribution of a single non-diffraction beam is obtained, and then the multi-beam array reflection phase distribution that satisfies the condition formula is calculated. Step S5: Utilize the condition formula that the array reflection phase distribution of the multi-beam antenna satisfies the condition formula, and then design the unit structure at different coordinates based on the relationship between the reflection phase obtained in step S1 and the two parameters of the first distance p1w and the second distance p2w, and finally obtain the required array unit structure and obtain the dual-frequency diffraction-free multi-beam antenna. In step S2, the phase distribution formula for a diffraction-free focused beam is used: The phase distribution of the array reflection generated by the diffraction-free focused beam was calculated. ,in, Let x be the wave number, and let y be the surface of the array element, which is equivalent to a two-dimensional plane xoy, where x and y are the coordinates of the element on the xoy plane. It is half the design angle of the equivalent pyramidal lens of the array unit; In step S3, the array reflection phase distribution corresponding to any deflection angle beam is obtained by calculation using the generalized Snell's law of refraction. ,in Let x and y be the wavenumber, and x and y be the coordinates of the array element on the array surface (xoy). and These represent the beam deflection angles in the x and y directions, respectively.

3. The dual-frequency diffraction-free multi-beam antenna based on metasurfaces according to claim 2, characterized in that, By superimposing the array reflection phase distributions calculated in steps S2 and S3, the array reflection phase distribution of a single non-diffraction beam is obtained. Then, the multi-beam array reflection phase distribution satisfying the condition formula is calculated. The specific formula is as follows: （1） The required array reflection phase distribution is obtained based on the focusing range and deflection angle requirements. Then, the array reflection phase distributions of the pre-generated multiple beams are calculated, and the vector sum of the multiple beams is calculated using the principle of electric field superposition, as shown in the following formula: （2） in, Let represent the electric field at coordinates (x, y) on the hypersurface. The amplitude at that point. The phase of the electric field at that point is the amplitude and phase that the beam emitted by the feed needs to be adjusted to after passing through the metasurface.

4. The dual-frequency diffraction-free multi-beam antenna based on metasurfaces according to claim 3, characterized in that, The final generated multi-beam array reflection phase distribution satisfies: Then, based on the relationship between the reflection phase obtained in step S1 and the two parameters of the first distance p1w and the second distance p2w, the unit structure at different coordinates is designed, and the required array unit is finally obtained.

Images