Parameter design method of dielectric-based metasurface for enhancing millimeter wave perception and dielectric-based metasurface

Abstract

The invention discloses a parameter design method of a dielectric-based metasurface for enhancing millimeter wave perception and the dielectric-based metasurface, and belongs to the field of radar perception. The dielectric-based metasurface comprises a metal film layer and a plurality of dielectric-based units which are arranged on the metal film layer and are tightly arranged; the metasurface regulates and controls the phase by regulating and controlling the thickness change of the dielectric base unit. On the basis, optional phase values of phases of the dielectric base units are discretized, a phase set containing n candidate phases is obtained, then the optimal phases of the dielectric base units are determined with the purpose of minimizing the difference between a theoretical radiation pattern and a target radiation pattern of the dielectric base metasurface, and the thickness of each dielectric base unit is calculated. Therefore, the direction of each millimeter wave is accurately regulated; a circuit unit does not need to be designed, cost is low, damage is not prone to occurring, installation and maintenance are easy, millimeter waves can be regulated and controlled with low cost, and therefore the millimeter waves can be accurately propagated according to the target propagation direction.

Description

Technical Field

[0001] The present invention belongs to the field of radar perception, and more specifically, relates to a parameter design method of a dielectric-based metasurface for enhancing millimeter-wave perception and a dielectric-based metasurface. Background Art

[0002] Millimeter wave (mmWave) technology is seen as the foundation of 5G and other advanced communication technologies, and global operators are actively deploying this technology to cope with the explosive growth of mobile data demand and the shortage of low-frequency spectrum resources. Faced with this challenge, turning to the mmWave band has become an inevitable long-term strategy for wireless operators. However, the high-frequency characteristics of mmWave bring many challenges, such as high free-space propagation loss, significant penetration and insufficient diffraction capabilities, which lead to its limitations in traditional outdoor-to-indoor coverage, especially in modern building-dense areas such as urban canyons. These problems pose a major obstacle to the promotion of mmWave technology. Therefore, it is urgent to take measures to accurately control the reflection direction of mmWave to enhance mmWave perception and promote the further development of its technology.

[0003] In the prior art, smart surfaces are often used to control the propagation direction of millimeter waves. In order to enable millimeter waves to propagate accurately in the target propagation direction, a large number of circuit units are often needed to construct the above-mentioned smart surfaces, which are costly, easy to damage, and difficult to install and maintain, severely limiting the large-scale deployment of smart surfaces. Summary of the invention

[0004] In response to the above defects or improvement needs of the prior art, the present invention provides a parameter design method of a dielectric-based metasurface for enhancing millimeter-wave perception and a dielectric-based metasurface, the purpose of which is to control millimeter waves at a lower cost so that they can propagate accurately in the target propagation direction.

[0005] In order to achieve the above-mentioned object, in the first aspect, the present invention provides a parameter design method of a dielectric-based metasurface for enhancing millimeter wave perception; wherein the dielectric-based metasurface comprises: a metal film layer and M closely arranged dielectric-based units arranged on the metal film layer; M ≥ 1; the length and width of the minimum circumscribed rectangle of the cross section of the dielectric-based unit are both less than λ is the wavelength of the millimeter wave; the cross section is the cross section parallel to the metal film layer in the dielectric base unit;

[0006] The above parameter design method includes:

[0007] S1. Initialize phase set The number of phases n in the dielectric-based metasurface is determined to determine the number of dielectric-based units with different thicknesses in the dielectric-based metasurface;

[0008] S2, selecting a phase from the current phase set for each dielectric-based unit in the dielectric-based metasurface, so that the difference between the corresponding theoretical radiation pattern and the target radiation pattern is minimized;

[0009] S3. For each dielectric-based unit, determine its thickness based on its phase, and then construct a dielectric-based metasurface simulation model; according to the target unit direction vector The millimeter wave is incident into the dielectric-based metasurface simulation model for simulation, and the corresponding simulated radiation pattern is obtained;

[0010] S4. If the difference between the simulated radiation pattern and the target radiation pattern is less than or equal to the preset error, and the current number of iterations is less than or equal to the preset number of iterations, go to S6; otherwise, go to S5;

[0011] S5, modify the number of phases n, and go to S2 for iteration;

[0012] S6. For each dielectric base unit, its current phase is taken as its optimal phase, and its optimal thickness is determined based on its optimal phase.

[0013] Further preferably, the distance between any two adjacent dielectric-based units in the dielectric-based metasurface is a preset distance d;

[0014] The above phase number n satisfies:

[0015]

[0016] Wherein, ΔSLL is the preset sidelobe level error; Δθ is the preset millimeter wave beam pointing error; N + Represents the set of positive integers.

[0017] More preferably, in the above S1, the initial value of n is Indicates rounding up;

[0018] In the above S5, the modified phase number n is: increase by n.

[0019] Further preferably, any unit direction vector in the theoretical radiation pattern The intensity value at is:

[0020]

[0021] Where σ0 is the reflection gain of the dielectric base unit; is the phase corresponding to the mth dielectric base unit; j is the imaginary sign; is the position vector of the mth dielectric base unit relative to the reference dielectric base unit; the reference dielectric base unit is a dielectric base unit arbitrarily selected from the dielectric base metasurface; is the target unit direction vector when the millimeter wave is incident on the dielectric-based metasurface; Represents any unit direction vector after the millimeter wave is reflected by the dielectric metasurface.

[0022] Further preferably, the target radiation pattern is based on the target unit direction vector when the millimeter wave is incident on the dielectric-based metasurface Target unit direction vector after millimeter wave is reflected by dielectric metasurface and target sidelobe levels are calculated using the array synthesis method.

[0023] Further preferably, the phase corresponding to the mth dielectric base unit With its thickness t d,m The following relations are satisfied:

[0024]

[0025] Among them, Z d is the characteristic impedance of the dielectric base unit; Z0 is the characteristic impedance of air; t 0,m is the vertical distance between the upper surface of the mth medium base unit and the preset boundary; the minimum value of the vertical distance between the preset boundary and each medium base unit is greater than or equal to k d and k0 are the wave numbers of the millimeter wave signal in the dielectric base unit and in the air, respectively.

[0026] Further preferably, the distance between any two adjacent dielectric-based units in the dielectric-based metasurface is a preset distance d;

[0027] The value range of the number of dielectric base units M in the dielectric base metasurface is: Among them, HPBW min is the preset millimeter wave beamwidth.

[0028] Further preferably, the thickness of the metal film layer is in, is the frequency of the incident millimeter wave signal, c is the speed of light, σ and μ are the electrical conductivity and magnetic permeability of the metal film layer, respectively.

[0029] Further preferably, in S3, electromagnetic simulation software is used for simulation.

[0030] In a second aspect, the present invention provides a dielectric-based metasurface, comprising: a metal film layer and M closely arranged dielectric-based units arranged on the metal film layer; M ≥ 1; the length and width of the minimum circumscribed rectangle of the cross section of the dielectric-based unit are both less than λ is the wavelength of the millimeter wave; the cross section is the cross section parallel to the metal film layer in the dielectric base unit;

[0031] The thickness of each dielectric base unit is calculated by the parameter design method provided in the first aspect of the present invention.

[0032] Further preferably, the above-mentioned dielectric-based metasurface is obtained by 3D printing.

[0033] Further preferably, the material of the medium base unit is rigid plastic.

[0034] In a third aspect, the present invention provides an electronic device, comprising: a memory and a processor, wherein the memory stores a computer program, and the processor executes the parameter design method provided in the first aspect of the present invention when executing the computer program.

[0035] In a fourth aspect, the present invention further provides a computer-readable storage medium, which includes a stored computer program, wherein when the computer program is executed by a processor, the device where the storage medium is located is controlled to execute the parameter design method provided in the first aspect of the present invention.

[0036] In a fifth aspect, the invention further provides a computer program product, including a computer program / instruction, which, when executed by a processor, implements the parameter design method provided in the first aspect of the invention.

[0037] In general, the above technical solutions conceived by the present invention can achieve the following beneficial effects:

[0038] 1. The present invention provides a parameter design method for a dielectric-based metasurface that enhances millimeter wave perception, wherein the dielectric-based metasurface includes: a plurality of closely arranged dielectric-based units arranged on a metal film layer; the metasurface controls the phase by adjusting the thickness change of the dielectric-based units. On this basis, the optional phase value of the dielectric-based unit phase is discretized to obtain a phase set containing n candidate phases, and then the optimal phase of the dielectric-based unit is determined with the goal of minimizing the difference between the theoretical radiation pattern of the dielectric-based metasurface and the target radiation pattern, and the thickness of each dielectric-based unit is calculated, so as to accurately control the direction of each millimeter wave; the present invention does not need to design a circuit unit, has a low cost, is not easy to damage, is simple to install and maintain, and can control millimeter waves at a low cost, so that it can accurately propagate in the target propagation direction.

[0039] 2. Further, in the parameter design method of the dielectric-based metasurface provided by the present invention, the number of phases n in the phase set satisfies: This can simultaneously constrain the millimeter-wave beam pointing error and sidelobe level error, thereby further improving the accuracy of millimeter-wave beam direction control.

[0040] 3. The present invention provides a dielectric-based metasurface that can be designed without electronic components or integrated circuits, has a simple structure and low cost. Due to its slim shape, small size and plasticity, it can be attached to the exterior walls of buildings, walls, billboards and other environments. It has a wide range of applications, can be widely deployed in various application scenarios, and is suitable for large-scale deployment.

[0041] 4. The dielectric-based metasurface provided by the present invention does not involve sensitive data and information transmission, and can ensure related security issues, thereby protecting personal privacy.

[0042] 5. Furthermore, the dielectric-based metasurface provided by the present invention can be obtained by 3D printing, which has a simple manufacturing process while maintaining a high level of precision. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Figure 1 A schematic structural diagram of a dielectric-based metasurface when the dielectric-based unit is a cuboid provided in an embodiment of the present invention;

[0044] Figure 2 A simulated radiation pattern of a dielectric-based metasurface provided in an embodiment of the present invention;

[0045] Figure 3 A schematic structural diagram of a one-dimensional binary dielectric-based metasurface provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0046] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0047] Existing smart surfaces have the following problems: 1) Current methods often require a large number of antenna units and control circuits, which are costly, easy to damage, and difficult to install and maintain, which severely limits their large-scale deployment. 2) Most of these technologies involve sensitive data and information transmission, which have certain security issues and are difficult to protect personal privacy. 3) High-density deployment may cause mutual interference between surfaces, thus affecting overall performance. 4) When facing high-frequency signals such as millimeter waves, the required circuits are more complex, with higher latency and greater limitations.

[0048] In order to solve the above problems, in the first aspect, the present invention provides a parameter design method for a dielectric-based metasurface for enhancing millimeter wave perception; wherein the dielectric-based metasurface comprises: a metal film layer and M closely arranged dielectric-based units arranged on the metal film layer; M ≥ 1; the length and width of the minimum circumscribed rectangle of the cross section of the dielectric-based unit are both less than To avoid aliasing; λ is the wavelength of the millimeter wave; the cross section is the cross section in the dielectric base unit parallel to the metal film layer; wherein the cross section of the dielectric base unit can be rectangular, square, circular, elliptical, triangular, etc., and correspondingly, the dielectric base unit can be in the shape of a cuboid, cylinder, elliptical cylinder, prism, etc., which is not limited here. The material of the dielectric base unit is a dielectric material, preferably a rigid plastic, such as nylon PA12, PLA, etc.

[0049] like Figure 1 The figure shows the dielectric-based metasurface when the dielectric-based unit is a rectangular parallelepiped. A dielectric-based unit and the metal film layer below it constitute a reflection unit; the dielectric-based unit and the metal film layer are used as the top and bottom of the reflection unit, respectively. Among them, the dielectric-based unit in the dielectric-based metasurface has various thicknesses, but they all have the same bottom, forming a flat dielectric surface. When multiple such reflection units are placed closely together, the corresponding metasurface looks like a dielectric plate with a flat bottom but many dielectric-based units etched on the top. Intuitively, the incident millimeter-wave signal must first pass through air gaps of different heights before entering the dielectric-based unit and reflecting back, so the unit element structure can be modeled as an air layer, a dielectric layer, and a conductive layer. According to the transmission line model, the input impedance Z of this layered structure is s is pure reactance:

[0050]

[0051] Phase distortion can be characterized by the complex reflection coefficient Γ at the top surface of the dielectric base unit, where the millimeter wave signal enters and exits the dielectric base unit. Intuitively, Γ describes how much of the wave is reflected by the impedance discontinuity between the transmission medium (such as air and the dielectric substrate). The formal definition of Γ is the ratio of the complex amplitude of the reflected wave to the complex amplitude of the incident wave, which can be characterized by the surface impedance of the dielectric surface:

[0052]

[0053] Among them, Z0 = 120πΩ is the impedance of free space.

[0054] Considering that the impedance of free space is pure resistance, the complex reflection coefficient of the reflection unit can be expressed as:

[0055]

[0056] Theoretically, given the thickness t of a unit element u =t d +t0, by changing the thickness of the dielectric base unit t d To adjust the phase shift of the incident millimeter-wave signal, which actually makes the reflection unit a phase shifter of the incident millimeter-wave signal; where t0 is the thickness of the air layer.

[0057] The above parameter design method includes:

[0058] S1. Initialize phase set The number of phases n in the dielectric-based metasurface is determined to determine the number of dielectric-based units with different thicknesses in the dielectric-based metasurface;

[0059] S2, selecting a phase from the current phase set for each dielectric-based unit in the dielectric-based metasurface, so that the difference between the corresponding theoretical radiation pattern and the target radiation pattern is minimized;

[0060] In an optional implementation manner, any unit direction vector in the theoretical radiation pattern The intensity value at is:

[0061]

[0062] Where, σ0 is the reflection gain of the dielectric base unit; is the phase corresponding to the mth dielectric base unit, j is the imaginary number symbol; is the position vector of the mth dielectric base unit relative to the reference dielectric base unit; the reference dielectric base unit is a dielectric base unit arbitrarily selected from the dielectric base metasurface; is the target unit direction vector when the millimeter wave is incident on the dielectric-based metasurface; represents any unit direction vector after the millimeter wave is reflected by the dielectric metasurface. and are the delays introduced by the different propagation distances of the incident and reflected signals of the unit element.

[0063] In an optional implementation, an xyz coordinate system is established with the center point of the minimum circumscribed rectangle of the cross section of the reference medium base unit on the metal film layer as the origin; wherein the xy plane is located on the upper surface of the metal film layer; on the xy plane, the target unit direction vector of the incident signal Unit direction vector of the reflected signal θ∈[0°,180°],θ and Corresponding; the target unit direction vector after the millimeter wave is reflected by the dielectric metasurface θ i , θ and θ rare the incident angle, the outgoing angle and the target outgoing angle respectively.

[0064] It should be noted that the target radiation pattern is predetermined by the user; preferably, in order to achieve or approximate the optimal pattern, in an optional implementation, the target radiation pattern is based on the target unit direction vector when the millimeter wave is incident on the dielectric-based metasurface Target unit direction vector after millimeter wave is reflected by dielectric metasurface and target sidelobe levels are calculated using the array synthesis method.

[0065] It should be noted that there are many array synthesis methods, such as Dolph-Chebyshev synthesis, Taylor synthesis, Baylis synthesis, Woodward synthesis, Gaussian distribution, etc. In an optional implementation, the Chebyshev synthesis method is used to generate the target radiation pattern, and the required incident angle is set to 40 degrees, the reflection angle is 55 degrees, and the sidelobe level is -20 dB.

[0066] It should be noted that there are many ways to express the difference between the theoretical radiation pattern and the target radiation pattern. In an optional implementation, sampling is performed from [0°, 180°] to obtain multiple continuous sampling points θ, and the difference between the theoretical radiation pattern and the target radiation pattern is expressed as F θ is the emission angle θ in the theoretical radiation pattern (with respect to the unit direction vector The intensity of the corresponding point; is the intensity at the exit angle θ in the target radiation pattern. In an optional implementation mode 2, only the intensity within a preset angle range centered on the target exit angle after the millimeter wave is reflected by the dielectric metasurface is concerned. The difference between the theoretical radiation pattern and the target radiation pattern is expressed as Δθ is a preset angle span, preferably 20°. In order to further simplify the calculation, in an optional implementation mode three, only the intensity of the millimeter wave at the target exit angle after being reflected by the dielectric-based metasurface is concerned, and the difference between the theoretical radiation pattern and the target radiation pattern is expressed as is the target emission angle θ in the theoretical radiation pattern r (with the target unit direction vector The intensity of the corresponding point; is the target emission angle θ in the target radiation pattern r The intensity of the place.

[0067] It should be noted that there are many methods for solving this optimization problem, such as discrete binary particle swarm algorithm, exhaustive method, iterative Fourier transform, differential evolution algorithm, differentiable pattern synthesis method, etc. Preferably, in an optional implementation, discrete binary particle swarm algorithm is used for solving; specifically, firstly, the particle phase is initialized, and binary code is generated according to a certain strategy:

[0068]

[0069] The phase is continuously updated using probability mapping, and the sigmoid function is used to map the velocity to the interval [0,1] as the probability. This probability is the probability that the particle will take the value π in the next step.

[0070]

[0071] s(v md ) indicates the current phase With a probability of π, the particle changes its phase value by the following formula:

[0072]

[0073] S3. For each dielectric-based unit, determine its thickness based on its phase, and then construct a dielectric-based metasurface simulation model; according to the target unit direction vector The millimeter wave is incident into the dielectric-based metasurface simulation model for simulation, and the corresponding simulated radiation pattern is obtained;

[0074] In an optional implementation manner, the phase corresponding to the mth dielectric base unit With its thickness t d,m The following relations are satisfied:

[0075]

[0076] Among them, Z d is the characteristic impedance of the dielectric base unit; Z0 is the characteristic impedance of air; t 0,m is the vertical distance between the upper surface of the mth medium base unit and the preset boundary; the minimum value of the vertical distance between the preset boundary and each medium base unit is greater than or equal to k d and k0 are the wave numbers of the millimeter wave signal in the dielectric base unit and in the air, respectively.

[0077] In an optional implementation, in S3, electromagnetic simulation software is used for simulation. It should be noted that there are many types of electromagnetic simulation software, such as CST, ADS, AWR, Ansys Designer, Ansys HFSS software, etc. There are many types of 3D modeling software, such as Solidworks, AutoCAD, UnigraphicsNX, Pro / Engineer, etc. This embodiment uses Solidworks to build a dielectric-based metasurface simulation model, and uses Ansys HFSS software to simulate and verify the single / dual-base RCS characteristics of a completely passive rough surface. The resulting simulated radiation pattern is shown in FIG. Figure 2 shown.

[0078] S4. If the difference between the simulated radiation pattern and the target radiation pattern is less than or equal to the preset error, and the current number of iterations is less than or equal to the preset number of iterations, go to S6; otherwise, go to S5;

[0079] It should be noted that there are many ways to express the difference between the simulated radiation pattern and the target radiation pattern. In an optional implementation, sampling is performed from [0°, 180°] to obtain multiple continuous sampling points θ, and the difference between the simulated radiation pattern and the target radiation pattern is expressed as F′ θ is the emission angle θ in the simulated radiation pattern (with respect to the unit direction vector The intensity of the corresponding point; is the intensity at the exit angle θ in the target radiation pattern. In an optional implementation mode 2, only the intensity within a preset angle range centered on the target exit angle after the millimeter wave is reflected by the dielectric metasurface is concerned. The difference between the simulated radiation pattern and the target radiation pattern is expressed as Δθ is the preset angle span, preferably 20°. In order to further simplify the calculation, in an optional implementation mode three, only the intensity of the millimeter wave at the target exit angle after being reflected by the dielectric-based metasurface is concerned, and the difference between the simulated radiation pattern and the target radiation pattern is expressed as is the target emission angle θ in the simulated radiation pattern r (with the target unit direction vector The intensity of the corresponding point; is the target emission angle θ in the target radiation pattern r The intensity of the place.

[0080] It should be noted that the preset error and the preset number of iterations can be set according to user needs and actual scenarios. In an optional implementation, the preset error is set to 10 6 , the preset number of iterations is 20.

[0081] S5, modify the number of phases n, and go to S2 for iteration;

[0082] S6. For each dielectric base unit, its current phase is taken as its optimal phase, and its optimal thickness is determined based on its optimal phase.

[0083] In an optional implementation manner, the distance between any two adjacent dielectric-based units in the dielectric-based metasurface is a preset distance d;

[0084] The above phase number n satisfies:

[0085]

[0086] Wherein, ΔSLL is the preset sidelobe level error; Δθ is the preset millimeter wave beam pointing error; N + Represents the set of positive integers.

[0087] Specifically, the present invention mainly relates to phase, so the influence of phase error needs to be considered. The phase error is First, phase error often causes beam pointing error, so Convertible And cosθ r ≤1, then Similarly, for random phases but In order to make n able to simultaneously constrain the beam pointing error and sidelobe level error of the millimeter wave, we have Among them SLL quant To quantify the sidelobe level; SLL ideal is the ideal sidelobe level; ΔSLL is the preset sidelobe level error; Δθ is the beam pointing error, θ r is the target beam pointing angle.

[0088] Therefore, in this implementation, the requirements for sidelobe level and directivity are relatively low, and only the sensing range needs to be expanded. Therefore, the error ΔSLL between the quantized sidelobe level and the ideal sidelobe level can reach 5dB, the beam pointing error Δθ can reach 10 degrees, and the target beam pointing angle θ r is 55 degrees, then the initial value of n is calculated to be 2.

[0089] Preferably, in an optional implementation manner, in the above S1, the initial value of n is Indicates rounding up;

[0090] In S5, the above-mentioned modification of the phase number n is: increasing n. Preferably, n is incremented by 1 successively.

[0091] Preferably, in an optional implementation manner, the spacing between any two adjacent dielectric-based units in the dielectric-based metasurface (the spacing between the center points of the minimum circumscribed rectangle of the cross-section of any two adjacent dielectric-based units in the dielectric-based metasurface) is a preset spacing d;

[0092] The value range of the number of dielectric base units M in the dielectric base metasurface is: Among them, HPBW min is the preset millimeter wave beamwidth.

[0093] The user can set any value for M within the value range of M. In addition to the user's specification, it can also be determined in the following manner. Preferably, in an optional implementation, the above S1 also includes: initializing the number of dielectric-based units in the dielectric-based metasurface to

[0094] The above S5 also includes: before going to S2: increasing the number of medium base units;

[0095] The above S6 also includes: taking the current number of the medium-based units as the optimal number of the medium-based units.

[0096] Preferably, in an optional embodiment, the material of the metal film layer can be copper, silver, aluminum, etc., with a thickness of in, is the frequency of the incident millimeter wave signal, c is the speed of light, σ and μ are the electrical conductivity and magnetic permeability of the metal film layer, respectively.

[0097] like Figure 3 As shown, in an optional embodiment, the dielectric base unit is in the shape of a cuboid, and when the thickness of all dielectric base units on the same horizontal line perpendicular to the incident plane is kept equal, the phase shift caused is also the same. At this time, the dielectric base metasurface is a one-dimensional binary dielectric base metasurface. The surface works within the millimeter wave spectrum range, has a wide field angle covering the azimuth direction, and can achieve controllable adjustment of the reflected beam direction along a single dimension. In this embodiment, the material of the dielectric base unit is nylon PA12. In view of the application requirements of the millimeter wave spectrum bandwidth of 77-78GHz, the size of the dielectric base unit in this embodiment is set to be 0.95 mm in length and width. In order to achieve a phase change of 0 to 180 degrees, according to the relationship between the thickness and phase of the dielectric base unit, the thickness of the dielectric base unit is designed to be in the range of 0.6 mm to 1.8 mm. Further, the metal film layer in this embodiment is made of copper material with a thickness of about 40 nanometers to provide the required reflection characteristics. When constructing the dielectric base metasurface, this embodiment selects a number of 50×50 dielectric base units.

[0098] By designing the above parameters, the phase shift changes of multiple dielectric-based units can be precisely controlled to achieve controllable adjustment of the direction of the reflected beam, thereby achieving flexibility and efficiency in beam pointing.

[0099] In a second aspect, the present invention provides a dielectric-based metasurface, comprising: a metal film layer and M closely arranged dielectric-based units arranged on the metal film layer; M ≥ 1; the length and width of the minimum circumscribed rectangle of the cross section of the dielectric-based unit are both less than λ is the wavelength of the millimeter wave; the cross section is the cross section parallel to the metal film layer in the dielectric base unit;

[0100] The thickness of each dielectric base unit is calculated by the parameter design method provided in the first aspect of the present invention. The related technical solution is the same as the parameter design method provided in the first aspect of the present invention, and will not be described in detail here.

[0101] In an optional implementation, the above-mentioned dielectric-based metasurface is obtained by 3D printing. Specifically, after obtaining the above-mentioned parameters, a 3D model of the dielectric-based metasurface is designed using a 3D modeling software, and then slicing, 3D printing, post-processing and other operations are performed to obtain a 3D-printed completely passive rough surface object. Specifically, this embodiment uses Solidworks for modeling, and then 3D printing is performed on the established model. In order to reduce the impact of quantization errors in 3D printing, the size of the dielectric-based unit in the dielectric-based metasurface can be increased as much as possible.

[0102] In an optional embodiment, the material of the dielectric base unit is a dielectric material, preferably a rigid plastic, such as nylon PA12, PLA, etc.

[0103] In summary, the present invention designs a dielectric-based metasurface that is economical, efficient, widely applicable, stable, reliable, and privacy-guaranteed for modern building-dense areas such as urban canyons. The metasurface is composed of a series of closed reflective units, and the thickness of the dielectric-based unit on the top of the reflective unit is adjusted to achieve precise reshaping and redirection of the millimeter-wave beam, thereby effectively covering the perception blind spots and significantly expanding the perception range of millimeter waves at low cost.

[0104] In a third aspect, the present invention provides an electronic device, comprising: a memory and a processor, wherein the memory stores a computer program, and the processor executes the parameter design method provided in the first aspect of the present invention when executing the computer program.

[0105] The related technical solution is the same as the parameter design method provided in the first aspect of the present invention, and will not be described in detail here.

[0106] In a fourth aspect, the present invention further provides a computer-readable storage medium, which includes a stored computer program, wherein when the computer program is executed by a processor, the device where the storage medium is located is controlled to execute the parameter design method provided in the first aspect of the present invention.

[0107] The related technical solution is the same as the parameter design method provided in the first aspect of the present invention, and will not be described in detail here.

[0108] In a fifth aspect, the invention further provides a computer program product, including a computer program / instruction, which, when executed by a processor, implements the parameter design method provided in the first aspect of the invention.

[0109] The related technical solution is the same as the parameter design method provided in the first aspect of the present invention, and will not be described in detail here.

[0110] It will be easily understood by those skilled in the art that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A parameter design method for a dielectric-based metasurface for enhancing millimeter-wave perception, characterized in that: The dielectric-based metasurface comprises: a metal film layer and M closely arranged dielectric-based units arranged on the metal film layer; M≥1; the length and width of the minimum circumscribed rectangle of the cross section of the dielectric-based unit are both less than λ is the wavelength of the millimeter wave; the cross section is a cross section in the dielectric base unit parallel to the metal film layer; The parameter design method comprises: S1. Initialize phase set The number of phases n in ; S2, selecting a phase from the current phase set for each dielectric-based unit in the dielectric-based metasurface, so that the difference between the corresponding theoretical radiation pattern and the target radiation pattern is minimized; S3. For each dielectric-based unit, determine its thickness based on its phase, and then construct a dielectric-based metasurface simulation model; according to the target unit direction vector The millimeter wave is incident into the dielectric-based metasurface simulation model for simulation, and a corresponding simulated radiation pattern is obtained; S4. If the difference between the simulated radiation pattern and the target radiation pattern is less than or equal to a preset error, and the current number of iterations is less than or equal to a preset number of iterations, go to S6; otherwise, go to S5; S5, modify the phase number n, and go to S2 for iteration; S6. For each dielectric base unit, its current phase is taken as its optimal phase, and its optimal thickness is determined based on its optimal phase.

2. The parameter design method according to claim 1, characterized in that: The distance between any two adjacent dielectric-based units in the dielectric-based metasurface is a preset distance d; The phase number n satisfies: Wherein, ΔSLL is the preset sidelobe level error; Δθ is the preset millimeter wave beam pointing error; N + Represents the set of positive integers.

3. The parameter design method according to claim 2, characterized in that: In S1, the initial value of the phase number n is Indicates rounding up; In S5, the modifying of the phase number n is: increasing the phase number n.

4. The parameter design method according to claim 1, characterized in that: The distance between any two adjacent dielectric-based units in the dielectric-based metasurface is a preset distance d; The value range of the number M of dielectric-based units in the dielectric-based metasurface is: Among them, HPBW min is the preset millimeter wave beamwidth.

5. The parameter design method according to any one of claims 1 to 4, characterized in that: Any unit direction vector in the theoretical radiation pattern The intensity value at is: Where σ0 is the reflection gain of the dielectric base unit; is the phase corresponding to the mth dielectric base unit; j is the imaginary sign; is the position vector of the mth dielectric base unit relative to the reference dielectric base unit; the reference dielectric base unit is a dielectric base unit arbitrarily selected from the dielectric base metasurface; is the target unit direction vector when the millimeter wave is incident on the dielectric-based metasurface; Represents any unit direction vector after the millimeter wave is reflected by the dielectric metasurface.

6. The parameter design method according to any one of claims 1 to 4, characterized in that: The phase corresponding to the mth dielectric base unit With its thickness t d,m The following relations are satisfied: Among them, Z d is the characteristic impedance of the dielectric base unit; Z0 is the characteristic impedance of air; t 0,m is the vertical distance between the upper surface of the mth medium base unit and the preset boundary; the minimum value of the vertical distance between the preset boundary and each medium base unit is greater than or equal to k d and k0 are the wave numbers of the millimeter wave signal in the dielectric base unit and in the air, respectively.

7. The parameter design method according to any one of claims 1 to 4, characterized in that: The thickness of the metal film layer is in, is the frequency of the incident millimeter wave signal, c is the speed of light, σ and μ are the electrical conductivity and magnetic permeability of the metal film layer, respectively.

8. A dielectric-based metasurface, characterized in that: include: A metal film layer and M closely arranged dielectric base units arranged on the metal film layer; M≥1; the length and width of the minimum circumscribed rectangle of the cross section of the dielectric base unit are both less than λ is the wavelength of the millimeter wave; the cross section is a cross section in the dielectric base unit parallel to the metal film layer; Wherein, the thickness of each dielectric base unit is calculated by the parameter design method described in any one of claims 1-7.

9. The dielectric-based metasurface according to claim 8, characterized in that: Obtained through 3D printing.

10. An electronic device, characterized in that: include: A memory and a processor, wherein the memory stores a computer program, and the processor executes the parameter design method according to any one of claims 1 to 7 when executing the computer program.

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