Low-scattering metasurface rapid calculation and collaborative design method based on cubic phase and vortex phase distribution assistance

Abstract

The invention discloses a low-scattering metasurface rapid calculation and collaborative design method based on cubic phase and vortex phase distribution assistance, which comprises a plurality of metasurface units, the metasurface units present a double relationship between the phase and the rotation angle under the condition of circularly polarized wave incidence, and the metasurface units present a double relationship between the phase and the rotation angle. The unit comprises an upper dielectric layer, a resonator layer, a lower dielectric layer and a floor layer which are sequentially arranged from top to bottom. The resonator layer comprises at least two arc parts and an axis part; the arc parts are coaxially arranged, and the adjacent arc parts are connected through the axis part. According to the method, the cubic phase and the vortex phase are combined, the phase distribution of all elements of the metasurface is directly and efficiently calculated, the time-consuming steps of a traditional optimization design method are reduced, and a large amount of computer resources and time are saved. In addition, the phase calculation method only needs to consider the position distribution of the metasurface unit and is irrelevant to the located frequency band, so that the expandability of the frequency band is improved.

Description

TECHNICAL FIELD

[0001] The application relates to the field of RCS reduction technology, and in particular to a low-scattering metasurface fast calculation and collaborative design method based on cubic phase and vortex phase distribution assistance. BACKGROUND

[0002] With the increasing demand for stealth technology in military applications, how to effectively reduce the radar cross section (RCS) of a target and improve the broadband stealth performance thereof becomes more and more important. A metasurface is an artificial structure array formed by periodically or non-periodically arranging subwavelength units on a two-dimensional plane, and can flexibly control electromagnetic waves through polarization, phase, amplitude, frequency and the like. RCS reduction refers to reducing the backscattering of a target and enhancing the invisibility of the target to radar. In practical applications, it is generally considered that the RCS amplitude reduction value of a metasurface should be greater than or equal to 10 dB. Methods commonly used for RCS reduction include shape design, electromagnetic control and wave-absorbing materials.

[0003] At present, the design method of a metasurface mainly focuses on two aspects. On the one hand, a high-efficiency optimization algorithm is needed for a coded metasurface, which will consume a large amount of computer resources and time. On the other hand, the reduction of RCS and the improvement of design efficiency can be realized through a random phase distribution or a parabolic phase distribution, but there are problems of limited bandwidth and narrow scattering angle. SUMMARY

[0004] The application aims to provide a low-scattering metasurface fast calculation and collaborative design method based on cubic phase and vortex phase distribution assistance, so that the RCS can have a higher reduction amplitude value in a wide frequency range.

[0005] The technical solution for achieving the application is as follows: a low-scattering metasurface fast calculation and collaborative design method based on cubic phase and vortex phase distribution assistance, wherein the metasurface comprises a plurality of metasurface units, the phase and rotation angle of the unit are in a two-fold relationship under the condition of circularly polarized wave incidence, the unit comprises, from top to bottom, an upper dielectric layer, a resonator layer, a lower dielectric layer and a ground layer; the resonator layer comprises at least two circular arc portions and an axis portion; the circular arc portions are coaxially arranged, and the adjacent circular arc portions are connected through the axis portion.

[0006] A computer device comprises a memory, a processor and a computer program stored on the memory and executable on the processor, wherein the processor implements the steps of the above method when executing the program.

[0007] A computer readable storage medium has a computer program stored thereon, and the program is executed by a processor to implement the steps of the above method.

[0008] Compared with existing technologies, the significant advantages of this invention are: This invention combines cubic and vortex phases to directly and efficiently calculate the phase distribution of each element on the metasurface, reducing the time-consuming steps of traditional optimization design methods and saving significant computer resources and time. Furthermore, this phase calculation method only needs to consider the positional distribution of the metasurface elements and is independent of the frequency band. This is beneficial for improving the scalability of the frequency band. When circularly polarized plane waves irradiate the metasurface at different angles, the designed metasurface can significantly reduce the RCS and achieve a diffuse reflection mode. The designed metasurface can achieve an RCS reduction of more than 10 dB under the condition of circularly polarized wave incidence, exhibiting good far-field scattering effects. Attached Figure Description

[0009] Figure 1 This is a top view of the model of the basic unit in the embodiment of the present invention.

[0010] Figure 2 This is a side view of the model of the basic unit in an embodiment of the present invention.

[0011] Figure 3 This is a graph showing the relationship between the common polarization and cross polarization of the basic unit in the embodiments of the present invention and the frequency.

[0012] Figure 4 This is a graph showing the relationship between the geometric phase of the basic unit in the embodiment of the present invention and the rotational phase of the unit under the incident conditions of left-handed and right-handed circularly polarized waves.

[0013] Figure 5 This is a schematic diagram of the phase arrangement of the metasurface array units in an embodiment of the present invention.

[0014] Figure 6 This is a physical image of the metasurface processing in an embodiment of the present invention.

[0015] Figure 7 These are the scattering patterns of the PEC metal plate of equivalent size in the embodiments of the present invention, and the three-dimensional scattering patterns of the metasurface at frequency points of 8GHz, 12GHz, 16GHz, 20GHz, 24GHz, and 28GHz.

[0016] Figure 8 This is a two-dimensional cross-sectional comparison of the equivalent metal plate and metasurface at 8GHz, 15GHz, 21GHz, and 28GHz frequencies under left-handed circularly polarized wave incident conditions in an embodiment of the present invention.

[0017] Figure 9 This is a physical fabrication diagram of the metasurface array in the embodiment of the present invention.

[0018] Figure 10This is a comparison chart of the simulated RCS reduction curve and the measured RCS reduction curve of the metasurface in the embodiment of the present invention in the range of 7GHz-28GHz under the condition of perpendicular incidence of circularly polarized waves. Detailed Implementation

[0019] To address the aforementioned issues, this invention proposes a rapid computation and co-design method for low-scattering metasurfaces based on cubic and vortex phase distributions. This method comprises multiple rotating metasurface units, where the geometric phase and rotational phase of the metasurface units exhibit a two-fold relationship under circularly polarized wave incidence.

[0020] The basic unit of the metasurface includes, from top to bottom, an upper dielectric layer, a resonator layer, a lower dielectric layer, and a ground layer;

[0021] The resonator layer has two arc sections and one axial section; the arc sections are coaxially arranged and adjacent arc sections are connected by the axial section.

[0022] The radius of the arc-shaped portion is 2.8 mm, the length of the axial portion is 2.6 mm, and the width is 0.45 mm; the length and width of the basic unit are both 6 mm.

[0023] The resonator layer of the aforementioned metasurface for RCS reduction has a thickness of 0.018 mm and a ground plane layer thickness of 0.035 mm.

[0024] The thickness of the upper dielectric layer is 2.25 mm, the thickness of the lower dielectric layer is 2.5 mm, the relative permittivity is 2.2, and the loss tangent is 0.001.

[0025] The basic unit of the metasurface used for RCS reduction has a cross-polarization value of <-10dB and a cross-polarization value of -1dB to 0dB in the frequency range of 6.9GHz to 28.9GHz.

[0026] When a circularly polarized wave is incident, the geometric phase of the basic metasurface unit changes with the rotation angle, exhibiting a 2-fold relationship.

[0027] When a left-handed circularly polarized wave is incident, the geometric phase and rotation angle of the metasurface basic unit are negatively correlated; when a right-handed circularly polarized wave is incident, the geometric phase and rotation angle of the unit are positively correlated.

[0028] The metasurface comprises 900 metasurface units arranged in a 30×30 pattern, and the metasurface is used to achieve RCS reduction under circularly polarized wave incident.

[0029] The metasurface uses cubic phase and vortex phase to calculate the phase arrangement of the metasurface unit, as shown in formula (3), and then calculates the rotation phase of the unit to determine the specific arrangement of the unit in the metasurface array, as shown in formula (4).

[0030]

[0031] In the formula, (x pos ,x pos ) represents the position of the metasurface unit, D is the aperture size of the metasurface, α is the coefficient of the cubic phase, and l is the number of topological modes of the vortex phase. After calculating the metasurface phase distribution φ hybrid Then, the rotation angle φ of each element can be calculated by using the relationship that the geometric phase is twice the rotation phase. rotate .

[0032] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be described in further detail below.

[0033] Example

[0034] refer to Figure 1 , Figure 2 As the basic unit for RCS reduction of the metasurface in this embodiment, it includes, from top to bottom, an upper dielectric layer 10, a resonator layer 20, a lower dielectric layer 30, and a ground layer 40. The resonator layer 20 and the ground layer 40 are both made of copper, and the dielectric layers 10 and 30 are both made of F4B. The thickness of the resonator layer 20 and the ground layer 40 is 0.018 mm. The upper dielectric layer 10 has a thickness of 2.25 mm, and the lower dielectric layer 30 has a thickness of 2.5 mm, with a relative permittivity of 2.2 and a loss tangent of 0.001.

[0035] The resonator layer 20 includes two arcuate portions 21 and one axial portion 22. The arcuate portions are coaxially arranged, and the arcuate portions 21 are connected by the axial portion 22. The specific parameters are as follows: the radius R of the arcuate portion 21 is 2.8 mm, the length G of the axial portion 22 is 2.6 mm, and the width W is 0.45 mm.

[0036] The overall width P of the basic unit is 6mm, and the basic units are arranged horizontally (i.e., with...). Figure 1 When the y-axis is parallel to the horizontal axis, the rotation angle is 0°. In other states, the rotation angle refers to the angle when the horizontal arrangement is rotated counterclockwise to that state.

[0037] Based on the basic unit of the above structure, simulation was performed using CST electromagnetic simulation software. Considering periodic boundary conditions in the X and Y directions, and with the electromagnetic wave propagating along the negative Z-axis, the simulation yielded curves showing the variation of common polarization and cross-polarization within the frequency range of 6 GHz to 30 GHz. The results are as follows: Figure 3 As shown in the figure, the basic unit has a cross-polarization value of <-10dB and a cross-polarization value of -1dB to 0dB in the frequency range of 6.9GHz to 28.9GHz.

[0038] Furthermore, simulations were performed to show the relationship between the geometric phase of the basic element and the rotational phase under left-handed circularly polarized wave (LHCP) and right-handed circularly polarized wave (RHCP) incident conditions, respectively. The results are as follows: Figure 4 As shown, it was found that the geometric phase changes with the rotation angle by approximately 2. When a left-handed circularly polarized wave is incident, the geometric phase of the basic element is negatively correlated with the rotation angle; when a right-handed circularly polarized wave is incident, the geometric phase of the element is positively correlated with the rotation angle.

[0039] Furthermore, the distribution of the metasurface phase is calculated using the following formula, with α = 50 and l = 1, and the results are output as follows. Figure 5 As shown.

[0040]

[0041] In the formula, (x pos ,x pos ) represents the position of the metasurface unit, D is the aperture size of the metasurface, α is the coefficient of the cubic phase, and l is the number of topological modes of the vortex phase. After calculating the metasurface phase distribution φ hybrid Then, the rotation angle φ of each element can be calculated by using the relationship that the geometric phase is twice the rotation phase. rotate .

[0042] Furthermore, using the calculated metasurface phase distribution, a metasurface model is constructed, such as... Figure 6 As shown. The RCS performance of the metasurface array was simulated using the electromagnetic simulation software CST. Figure 7 The paper presents the scattering pattern of a PEC metal plate of equivalent size, as well as the three-dimensional scattering patterns of the metasurface at frequencies of 8 GHz, 12 GHz, 16 GHz, 20 GHz, 24 GHz, and 28 GHz. Furthermore, in... Figure 8 Two-dimensional cross-sectional comparison diagrams are presented at frequency points of 8 GHz, 15 GHz, 21 GHz, and 28 GHz under left-handed circularly polarized wave incidence. Furthermore, in... Figure 9 The paper presents a physical fabrication diagram of the metasurface array. Figure 10The paper presents a comparison between the simulated and measured RCS reduction curves of the metasurface in the range of 7 GHz to 28 GHz under the condition of perpendicular incidence of circularly polarized waves.

[0043] The above embodiments are only used to illustrate the principles and effects of the present invention and do not limit its application scope. While maintaining the core spirit and scope of the present invention, experts in the art can make flexible adjustments and innovations. Therefore, any equivalent modifications or changes guided by the spirit and technical ideas of the present invention are within the protection scope of the present invention.

Claims

1. A fast computational and co-design method for low-scattering metasurfaces based on cubic phase and vortex phase distributions, characterized in that, The metasurface comprises multiple metasurface units. When a circularly polarized wave is incident, the phase and rotation angle of each unit are twice that of the other unit. Each unit includes, from top to bottom, an upper dielectric layer, a resonator layer, a lower dielectric layer, and a ground layer. The resonator layer includes at least two arcuate portions and an axial portion. The arc portions are coaxially arranged, and adjacent arc portions are connected by an axis portion.

2. The method as described in claim 1, characterized in that, The resonator layer has two arc-shaped portions and one axial portion. The radius of the arc-shaped portions is 2.8 mm, the length of the axial portion is 2.6 mm, and the width is 0.45 mm. The length and width of the metasurface unit are both 6 mm.

3. The method as described in claim 2, characterized in that, The thickness of the resonator layer and the ground layer is 0.018 mm; the thickness of the upper dielectric layer is 2.25 mm, the thickness of the lower dielectric layer is 2.5 mm, the relative permittivity is 2.2, and the loss tangent is 0.

001.

4. The method as described in claim 3, characterized in that, The basic unit has a cross-polarization value of <-10dB and a cross-polarization value of -1dB to 0dB in the frequency range of 6.9GHz to 28.9GHz.

5. The method as described in claim 4, characterized in that, When a circularly polarized wave is incident, the geometric phase of the metasurface unit changes with the rotation angle, exhibiting a doubling relationship. When a left-handed circularly polarized wave is incident, the geometric phase of the unit is negatively correlated with the rotation angle. When a right-handed circularly polarized wave is incident, the geometric phase of the unit is positively correlated with the rotation angle.

6. The method as described in claim 5, characterized in that, The metasurface comprises 900 metasurface units arranged in a 30×30 grid.

7. The method as described in claim 6, characterized in that, RCS reduction under circularly polarized wave incidence is achieved using metasurfaces.

8. The method as described in claim 7, characterized in that, The phase arrangement of the metasurface elements is calculated using cubic and vortex phases, as shown in formula (1). Then, the rotation phase of the elements is calculated to determine the specific arrangement of the elements in the metasurface array, as shown in formula (2). In the formula, (x pos ,x pos ) represents the position of the metasurface unit, D is the aperture size of the metasurface, α is the coefficient of the cubic phase, and l is the number of topological modes of the vortex phase; after calculating the metasurface phase distribution φ hybrid Then, the rotation angle φ of each element is calculated based on the relationship that the geometric phase is twice the rotation phase. rotate .

9. A computer device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that, When the processor executes the program, it implements the steps of the method according to any one of claims 1-8.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that, When executed by a processor, the program implements the steps of the method described in any one of claims 1-8.

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