A parameter design method of a medium-based metasurface for enhancing millimeter wave perception and a medium-based metasurface

Abstract

The application discloses a parameter design method of a medium-based metasurface for enhancing millimeter wave perception and a medium-based metasurface, and belongs to the field of radar perception.The medium-based metasurface comprises a metal film layer and a plurality of closely arranged medium-based units arranged on the metal film layer; and the metasurface adjusts the phase by adjusting the thickness of the medium-based units.Based on this, the optional phase values of the medium-based units are discretized to obtain a phase set containing n candidate phases, then the optimal phase of the medium-based units is determined by minimizing the difference between the theoretical radiation pattern of the medium-based metasurface and the target radiation pattern, and the thickness of each medium-based unit is calculated, so that the direction of each millimeter wave is accurately adjusted.The application does not need to design a circuit unit, has low cost, is not easy to be damaged, is simple to install and maintain, can adjust the millimeter wave at a low cost, so that the millimeter wave can accurately propagate according to the target propagation direction.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of radar perception, and more particularly, relates to a parameter design method of a medium-based metasurface for enhancing millimeter wave perception and a medium-based metasurface. BACKGROUND

[0002] Millimeter wave (mmWave) technology is considered as the basis for 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. In the face of this challenge, turning to the millimeter wave frequency band has become an unavoidable long-term strategy for wireless operators. However, the high-frequency characteristics of millimeter waves pose many challenges, such as higher free-space propagation loss, significant lack of penetration and diffraction ability, which limit its 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 millimeter wave technology. Therefore, it is urgent to take measures to accurately regulate the reflection direction of millimeter waves to enhance millimeter wave perception and promote the further development of its technology.

[0003] In the prior art, intelligent surfaces are often used to regulate the propagation direction of millimeter waves; in order to enable millimeter waves to propagate accurately according to the target propagation direction, a large number of circuit units are often designed to construct the above-mentioned intelligent surface, which is high in cost, easy to damage, difficult to install and maintain, and seriously limits the large-scale deployment of intelligent surfaces. SUMMARY

[0004] In view of the above defects or improvement needs of the prior art, the present application provides a parameter design method of a medium-based metasurface for enhancing millimeter wave perception and a medium-based metasurface, which aims to regulate millimeter waves at a lower cost so that they can propagate accurately according to the target propagation direction.

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

[0006] The above-mentioned parameter design method comprises:

[0007] S1, initialize a phase set to determine how many medium-based units with different thicknesses are in the medium-based metasurface;

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

[0009] S3, determining the thickness of each dielectric-based unit based on its phase, and then constructing a dielectric-based metasurface simulation model; according to the target unit direction vector Simulating the millimeter wave incident into the dielectric-based metasurface simulation model, and obtaining the corresponding simulation radiation pattern;

[0010] S4, if the difference between the simulation radiation pattern and the target radiation pattern is less than or equal to the preset error, and the current iteration number is less than or equal to the preset iteration number, then go to S6; otherwise, go to S5;

[0011] S5, modifying the phase number n, and going to S2 for iteration;

[0012] S6, for each dielectric-based unit, taking its current phase as its optimal phase, and determining its optimal thickness based on its optimal phase.

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

[0014] The phase number n satisfies:

[0015]

[0016] Where ΔSLL is a preset sidelobe level error; Δθ is a preset millimeter wave beam pointing error; N + represents a set of positive integers.

[0017] Further preferably, in the above S1, the initial value of n is represents the ceiling function;

[0018] In the above S5, the modification of the phase number n is: increasing n.

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

[0020]

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

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

[0023] Further preferably, the phase of the mth dielectric-based unit corresponds to and its thickness t d,m satisfies the following relationship:

[0024]

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

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

[0027] The number M of dielectric-based units in the dielectric-based metasurface ranges from: wherein HPBW min is the preset millimeter wave beam width.

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

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

[0030] In a second aspect, the present application 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 minimum circumscribed rectangle of the cross section of the dielectric-based unit has a length and a width, both of which are less than λ is the wavelength of the millimeter wave; the cross section is a cross section of the dielectric-based unit parallel to the metal film layer;

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

[0032] Further preferably, the dielectric base metasurface is obtained by 3D printing.

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

[0034] In a third aspect, the present application provides an electronic device, comprising a memory and a processor, wherein the memory stores a computer program, and the processor executes the computer program to execute the parameter design method provided by the first aspect of the present application.

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

[0036] In a fifth aspect, the present application further provides a computer program product, comprising computer programs / instructions, which, when executed by a processor, implement the parameter design method provided by the first aspect of the present application.

[0037] Overall, the above technical solutions conceived by the present application can achieve the following beneficial effects:

[0038] 1. The present application provides a parameter design method of a dielectric base metasurface for enhancing millimeter wave perception, wherein the dielectric base metasurface comprises a plurality of closely arranged dielectric base units arranged on a metal film layer; and the metasurface adjusts the phase by adjusting the thickness of the dielectric base units. On this basis, the selectable phase values of the dielectric base units are discretized to obtain a phase set containing n candidate phases, and then the optimal phase of the dielectric base units is determined to minimize the difference between the theoretical radiation pattern of the dielectric base metasurface and the target radiation pattern, and the thickness of each dielectric base unit is calculated, so as to accurately adjust the direction of each millimeter wave; the present application does not need to design circuit units, has low cost, is not easy to be damaged, and is simple to install and maintain, and can adjust millimeter waves at a low cost, so that the millimeter waves can accurately propagate according to the target propagation direction.

[0039] 2. Further, in the parameter design method of the dielectric base metasurface provided by the present application, the number n of phases in the phase set satisfies: to simultaneously constrain the beam pointing error and the sidelobe level error of the millimeter wave, so as to further improve the accuracy of the millimeter wave beam direction adjustment.

[0040] 3、The medium-based metasurface provided by the application can be designed without electronic components or integrated circuits, has simple structure and low cost, is thin in shape, small in size, and has plasticity, can be attached to the outer walls of buildings, walls, billboards and other environments, has wide application range, can be widely deployed in various application scenarios, and is suitable for large-scale deployment.

[0041] 4、The medium-based metasurface provided by the application does not involve sensitive data and information transmission, can guarantee relevant security issues, and thus protects personal privacy.

[0042] 5、Further, the medium-based metasurface provided by the application can be obtained by 3D printing, has simple manufacturing process, and at the same time maintains high precision level. BRIEF DESCRIPTION OF DRAWINGS

[0043] Figure 1 The structure schematic diagram of the medium-based metasurface when the medium-based unit is a cuboid is provided for the embodiment of the application.

[0044] Figure 2 The simulation radiation pattern of the medium-based metasurface is provided for the embodiment of the application.

[0045] Figure 3 The structure schematic diagram of the one-dimensional binary medium-based metasurface is provided for the embodiment of the application. DETAILED DESCRIPTION

[0046] In order to make the purpose, technical scheme and advantages of the application clearer, the application is further described in detail below with reference to the drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the application and do not limit the application. In addition, the technical features involved in each embodiment of the application described below can be combined with each other as long as they do not conflict with each other.

[0047] The existing intelligent surface has the following problems: 1) the current method often needs a large number of antenna units and control circuits, has high cost, is easy to damage, and is difficult to install and maintain, which seriously limits their large-scale deployment. 2) Most of these technologies involve sensitive data and information transmission, have certain security problems, and are difficult to protect personal privacy. 3) High-density deployment can cause mutual interference between surfaces, thereby affecting the overall performance. 4) When facing high-frequency signals such as millimeter waves, the required circuit is more complex, has higher delay, and has greater limitations.

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

[0049] As shown in Figure 1 the medium-based metasurface when the medium-based unit is a cuboid. One medium-based unit and the metal film layer thereunder form a reflection unit; the medium-based unit and the metal film layer are respectively taken as the top and bottom of the reflection unit. Among them, the medium-based units in the medium-based metasurface have various thicknesses, but they all have the same bottom, forming a flat medium surface. When a plurality of such reflection units are closely placed together, the corresponding meta-surface looks like a medium plate with a flat bottom but with many medium-based units etched on the top. Intuitively, the incident millimeter wave signal must first pass through the air gap of different heights before entering the medium-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 s of this layered structure is purely reactive:

[0050]

[0051] The phase distortion can be characterized by the complex reflection coefficient Γ of the top surface of the medium-based unit, and the millimeter wave signal enters and exits the medium-based unit from here. Intuitively, Γ describes how many waves are reflected by the impedance discontinuity between the transmission medium (such as air and medium base). 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 medium surface:

[0052]

[0053] where Z0 = 120πΩ is the impedance of free space.

[0054] Since the impedance of free space is purely resistive, the complex reflection coefficient of the reflection unit can be expressed as:

[0055]

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

[0057] The above parameter design method comprises:

[0058] S1, initializing the number n of phases in the phase set to determine how many different thicknesses of dielectric-based units in the dielectric-based metasurface;

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

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

[0061]

[0062] Where σ0 is the reflection gain of the dielectric-based unit; is the phase corresponding to the mth dielectric-based unit, j is the imaginary unit symbol; is the position vector of the mth dielectric-based unit relative to the reference dielectric-based unit; the reference dielectric-based unit is an arbitrarily selected dielectric-based unit from the dielectric-based metasurface; is the target unit direction vector when the millimeter wave is incident to the dielectric-based metasurface; represents any unit direction vector after the millimeter wave is reflected by the dielectric-based metasurface. In the formula, and are delays introduced by 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 dielectric-based unit on the metal film layer as the origin; wherein the xy plane is on the upper surface of the metal film layer; in the xy plane, the target unit direction vector of the incident signal the unit direction vector of the reflected signal θ∈[0°,180°], θ corresponds to the target unit direction vector of the reflected millimeter wave by the dielectric-based metasurface θ i , θ and θ rincident angle, exit angle and target exit angle, respectively.

[0064] It should be noted that the target radiation pattern is given by the user in advance; preferably, in order to achieve or approximate the optimal pattern, in an optional embodiment, the target radiation pattern is based on the target unit direction vector of the millimeter wave after being reflected by the medium-based metasurface target unit direction vector of the millimeter wave after being reflected by the medium-based metasurface and the target side lobe level are calculated by an array synthesis method.

[0065] It should be noted that there are many array synthesis methods, such as Doherty-Chebyshev synthesis method, Taylor synthesis method, Bellis synthesis method, Woodward synthesis method, Gaussian distribution, etc. In an optional embodiment, 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 set to 55 degrees, and the side lobe level is set to -20dB.

[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 embodiment, sampling is performed from [0°, 180°], obtaining a plurality of continuous sampling points θ, and the difference between the theoretical radiation pattern and the target radiation pattern is expressed as F θ is the intensity at the exit angle θ (corresponding to the unit direction vector ) in the theoretical radiation pattern; is the intensity at the exit angle θ in the target radiation pattern. In an optional embodiment two, only the intensity within a preset angle range centered on the target exit angle of the millimeter wave after being reflected by the medium-based metasurface is concerned, and 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 embodiment three, only the intensity at the target exit angle of the millimeter wave after being reflected by the medium-based metasurface is concerned, and the difference between the theoretical radiation pattern and the target radiation pattern is expressed as is the intensity at the target exit angle θ r (corresponding to the target unit direction vector ) in the theoretical radiation pattern; is the intensity at the target exit angle θ r in the target radiation pattern.

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

[0068]

[0069] The phase is continuously updated using a probability mapping method, 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 on the dielectric-based metasurface simulation model for simulation, and the corresponding simulated radiation pattern is obtained;

[0074] In an optional embodiment, the phase corresponding to the mth dielectric base unit 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 dielectric base unit and the preset boundary; the minimum vertical distance between the preset boundary and each dielectric 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, simulation is performed by using electromagnetic simulation software. It should be noted that there are various electromagnetic simulation software, such as CST, ADS, AWR, Ansys Designer, Ansys HFSS software, etc. There are various three-dimensional modeling software, such as Solidworks, AutoCAD, UnigraphicsNX, Pro / Engineer, etc. In the embodiment, Solidworks is used to construct the simulation model of the medium-based metasurface, and Ansys HFSS software is used to simulate and verify the single / dual base RCS characteristics of the completely passive metasurface. The obtained simulation radiation pattern is as shown in FIG. 2. Figure 2

[0078] S4, if the difference between the simulation radiation pattern and the target radiation pattern is less than or equal to the preset error, and the current iteration number is less than or equal to the preset iteration number, turn to S6; otherwise, turn to S5.

[0079] It should be noted that there are various expressions of the difference between the simulation radiation pattern and the target radiation pattern; in an optional implementation, sampling is performed from [0°, 180°], to obtain a plurality of continuous sampling points θ, and the difference between the simulation radiation pattern and the target radiation pattern is expressed as F′ θ is the intensity of the simulation radiation pattern at the exit angle θ (corresponding to the unit direction vector ); is the intensity of the target radiation pattern at the exit angle θ. In an optional implementation two, only the intensity in a preset angle range centered on the target exit angle of the millimeter wave reflected by the medium-based metasurface is concerned, and the difference between the simulation radiation pattern and the target radiation pattern is expressed as Δθ is a preset angle span, which is preferably 20°. In order to further simplify the calculation, in an optional implementation three, only the intensity at the target exit angle of the millimeter wave reflected by the medium-based metasurface is concerned, and the difference between the simulation radiation pattern and the target radiation pattern is expressed as is the intensity of the simulation radiation pattern at the target exit angle θ r (corresponding to the target unit direction vector ); is the intensity of the target radiation pattern at the target exit angle θ r .

[0080] It should be noted that the preset error and the preset iteration number can be set according to user demand and actual scene, and in an optional implementation, the preset error is 10 6 , and the preset iteration number is 20.​

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

[0082] S6, for each medium-based unit, take its current phase as its optimal phase and determine its optimal thickness based on its optimal phase.

[0083] In an optional embodiment, the spacing between any two adjacent medium-based units in the medium-based metasurface is a preset spacing d;

[0084] The phase number n satisfies:

[0085]

[0086] Where ΔSLL is a preset sidelobe level error; Δθ is a preset beam pointing error; N + represents a set of positive integers.

[0087] Specifically, the present application mainly relates to phase, so the influence of phase error needs to be considered. The phase error is Firstly, the phase error often causes an error in beam pointing, so can be converted to and cosθ r ≤1, then Similarly, for random phase, there is then In order to make n meet the constraint of the beam pointing error and the sidelobe level error of the millimeter wave, there is where SLL quant is the quantized sidelobe level; SLL ideal is the ideal sidelobe level; ΔSLL is the preset sidelobe level error; Δθ is the beam pointing error, and θ r is the target beam pointing angle.

[0088] Therefore, in the present embodiment, the requirements for the sidelobe level and the directivity are relatively low, and it is only necessary to expand the perception range. 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, so the initial value of n can be calculated as 2.

[0089] Preferably, in an optional embodiment, in S1, the initial value of n is represents the ceiling function;

[0090] In S5, the modification of the phase number n is to increase n. Preferably, n is increased by 1 each time.

[0091] Preferably, in an optional embodiment, 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-based units M in the dielectric-based 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 user specification, it can also be determined in the following ways. Preferably, in an optional embodiment, the above S1 also includes: initializing the number of dielectric base units in the dielectric base metasurface to

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

[0095] The above S6 also includes: taking the current number of dielectric base units as the optimal number of dielectric base 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 rectangular. When the thickness of all dielectric base units located on the same horizontal line perpendicular to the incident plane is equal, the resulting phase shift is also the same. In this case, the dielectric base metasurface is a one-dimensional binary dielectric base metasurface. This surface operates within the millimeter wave spectrum range, has a wide field of view covering the azimuthal angle, and can achieve controllable adjustment of the reflected beam direction along a single dimension. In this embodiment, the dielectric base unit is made of nylon PA12. To meet the application requirements of the millimeter wave spectrum bandwidth of 77-78 GHz, the dimensions of the dielectric base unit in this embodiment are set to 0.95 mm in length and width. To achieve a phase shift of 0 to 180 degrees, the thickness of the dielectric base unit is designed to be within the range of 0.6 mm to 1.8 mm based on the relationship between dielectric base unit thickness and phase. Furthermore, the metal film layer in this embodiment is made of copper with a thickness of approximately 40 nanometers to provide the required reflection properties. When constructing the dielectric base metasurface, this embodiment uses a 50×50 dielectric base unit number.

[0098] By designing the above parameters, the phase shift changes of multiple dielectric base units can be accurately controlled, the controllable adjustment of the reflected beam direction is realized, and thus the flexibility and efficiency of beam pointing are achieved.

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

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

[0101] In an optional embodiment, the above dielectric metasurface is obtained by 3D printing. Specifically, after obtaining the above parameters, a 3D model of the dielectric metasurface is designed using a three-dimensional modeling software, and then slicing processing, 3D printing, post-processing and other operations are performed to obtain a 3D printed complete passive rough surface physical object. Specifically, the present embodiment adopts Solidworks for modeling, and then the established model is 3D printed. In order to reduce the influence of 3D printing quantization error, the size of the dielectric base unit in the dielectric metasurface can be increased as much as possible.

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

[0103] In summary, the present application designs an economic, efficient, widely applicable, stable and reliable dielectric metasurface that protects privacy and security 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 base unit on the top of the reflective unit is controlled to realize accurate reshaping and reorientation of the millimeter wave beam, thereby effectively covering the blind area of perception, and significantly expanding the perception range of the millimeter wave under low-cost conditions.

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

[0105] The related technical solutions are the same as the parameter design method provided in the first aspect of the present application, and will not be repeated here.

[0106] In a fourth aspect, the present application provides a computer readable storage medium, which comprises a stored computer program, wherein the computer program, when executed by a processor, controls a device in which the computer readable storage medium is located to perform the parameter design method according to the first aspect of the present application.

[0107] The related technical solutions are the same as the parameter design method according to the first aspect of the present application, and thus are not described herein.

[0108] In a fifth aspect, the present application provides a computer program product, which comprises computer programs / instructions, and the computer programs / instructions, when executed by a processor, implement the parameter design method according to the first aspect of the present application.

[0109] The related technical solutions are the same as the parameter design method according to the first aspect of the present application, and thus are not described herein.

[0110] Those skilled in the art can easily understand that the above description is only the preferred embodiments of the present application, and is not intended to limit the present application, and any modification, equivalent replacement and improvement made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A parameter design method for a dielectric-based metasurface for enhancing millimeter-wave sensing, 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 thin 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 as to minimize the difference between the corresponding theoretical radiation pattern and the target radiation pattern; 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 injecting millimeter waves into the dielectric-based metasurface simulation model for simulation, and obtaining corresponding simulated radiation patterns; 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, take its current phase as its optimal phase, and determine its optimal thickness 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 number of phases 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 unit; j is the imaginary number 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 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 Its thickness t d,m The following relationship is 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 dielectric base unit and the preset boundary; the minimum value of the vertical distance between the preset boundary and each dielectric 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 thin film layer; The thickness of each dielectric base unit is calculated by the parameter design method described in any one of claims 1 to 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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