A method for realizing high-efficiency abnormal reflection with large deflection angle based on SCSMS

Abstract

The present invention discloses a method for realizing high-efficiency abnormal reflection with a large deflection angle based on SCSMS. The SCSMS includes a surface antenna and a radio frequency circuit. The surface antenna is used to receive incident electromagnetic waves in space and transmit and couple to a back-connected radio frequency circuit. The radio frequency circuit is used to realize a gradient change of a specific phase, and the guided wave echo signal is radiated back to the free space through the surface antenna. The present invention provides a new concept of using a metasurface to control the electrical properties of incident electromagnetic waves. The spatial electromagnetic waves are converted into guided waves through a surface antenna, and the guided waves are regulated through a radio frequency circuit, and the regulated guided waves are radiated back to the free space, thereby realizing the regulation of spatial electromagnetic waves. Based on this method, the SCSMS can be reasonably designed to realize high-efficiency abnormal reflection with a large rotation angle of 70 degrees; the SCSMS designed by the present invention can be conveniently applied to other frequency ranges, such as terahertz and optical regions.

Description

Technical Field

[0001] The present invention belongs to the technical field of reflective meta-electromagnetic surfaces, and in particular relates to a method for realizing high-efficiency abnormal reflection with a large deflection angle based on SCSMS. Background Art

[0002] Metasurface (MS) is a planar array structure composed of artificial structural units with subwavelength size and periodic lattice. It has unique electromagnetic wave manipulation properties, including the regulation of amplitude, phase and polarization degrees of freedom. In addition, its low profile, light weight and low cost have attracted continuous attention from the academic community and have broad application prospects. At present, many typical applications and functions have been generated based on metasurfaces, such as focusing, abnormal reflection (refraction), RCS reduction, etc. Among different types of metasurfaces, phase gradient metasurface (PGM) has been widely studied due to its significant characteristics in controlling the propagation direction of electromagnetic waves, modifying light wavefronts, generating abnormal reflection (refraction) phenomena and other electromagnetic wave distributions. It is an important basic and representative work in metasurfaces.

[0003] Traditional metasurfaces control their properties through direct interaction between surface impedance and electromagnetic waves. Due to the local non-periodicity of the metasurface, unnecessary electromagnetic coupling will occur between adjacent units, which will have an additional impact on the final electromagnetic wave control effect of the metasurface, especially when a large phase gradient change is required, which will reduce the efficiency of traditional PGM for beam control. Summary of the invention

[0004] The object of the present invention is to propose a method for realizing high-efficiency abnormal reflection with a large deflection angle based on SCSMS.

[0005] The technical solution to achieve the purpose of the present invention is as follows: In the first aspect, the present invention provides a method for realizing high-efficiency abnormal reflection with a large deflection angle based on SCSMS, comprising:

[0006] Using surface antennas to receive incident waves and radiate reflected waves;

[0007] Connecting the surface antenna to the RF circuit;

[0008] Determining radio frequency circuit parameters according to the gradient phase distribution of the reflection surface to be designed;

[0009] Use radio frequency circuits to control the characteristics of electromagnetic waves.

[0010] In the second aspect, the present invention also proposes a SCSMS capable of achieving high-efficiency abnormal reflection at a large deflection angle, comprising: a surface antenna and a radio frequency circuit, wherein the surface antenna is used to couple the received incident electromagnetic wave to a back-connected radio frequency circuit, and the radio frequency circuit is used to achieve total reflection and gradient changes in a specific reflection phase, and the guided wave reflected echo is radiated back into free space through the surface antenna.

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

[0012] (1) The present invention provides a new concept of using a metasurface to achieve high-efficiency abnormal reflection with a large deflection angle. The present invention acts on the incident electromagnetic wave in the circuit and controls the phase of the reflecting surface through the circuit. Unnecessary coupling is avoided and the abnormal reflection efficiency is improved;

[0013] (2) The present invention introduces the design of radio frequency circuits into the design of reflective metasurfaces, which increases the degree of freedom of the overall design and integrates the advantages of radio frequency circuit design in the process of controlling spatial electromagnetic waves;

[0014] (3) The structure of the present invention is simple, and the proposed SCSMS can be easily applied to other frequency ranges, such as the terahertz and optical regions.

[0015] The present invention is described in further detail below in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 Schematic diagram of SCSMS capable of achieving high-efficiency anomalous reflection at a large deflection angle.

[0017] Figure 2 A spatial illustration of the SCSMS that is capable of achieving highly efficient anomalous reflection at a large deflection angle.

[0018] Figure 3 Schematic diagram of the SCSMS unit structure utilizing high-efficiency anomalous reflection capable of achieving large deflection angles.

[0019] Figure 4 This is the antenna efficiency simulation diagram of the SCSMS element structure.

[0020] Figure 5 The simulation results of reflective SCSMS components with different back-load circuit lengths are shown in Figure 2.

[0021] Figure 6 This is the overall structural design diagram of the abnormal reflection SCSMS.

[0022] Figure 7 Comparison diagram of the reflection phase distribution along the x-axis between theoretical requirements and simulation results.

[0023] Figure 8This is the RCS simulation result of SCSMS and metal plate at 21.5GHz under y-polarization oblique 20° incidence conditions. DETAILED DESCRIPTION

[0024] The present invention proposes a method for realizing high-efficiency abnormal reflection with a large deflection angle based on a surface-circuit-surface metasurface (SCSMS), such as Figure 1 As shown, the method includes:

[0025] Using surface antennas to receive incident waves and radiate reflected waves;

[0026] Connecting the surface antenna to the RF circuit;

[0027] Determining radio frequency circuit parameters according to the gradient phase distribution of the reflection surface to be designed;

[0028] Use radio frequency circuits to control the characteristics of electromagnetic waves.

[0029] In a further embodiment, the surface antenna unit structure patterns are of uniform size.

[0030] In a further embodiment, the specific method for determining the radio frequency circuit parameters according to the gradient phase distribution of the reflection surface to be designed is:

[0031] The antenna efficiency of the unit structure under periodic boundary conditions is simulated and optimized according to the required working frequency band range, and a unit surface antenna structure with an aperture efficiency greater than 90% is obtained.

[0032] According to the reflection characteristics of the unit structure obtained by simulation when the terminal of the unit RF circuit is open, the reflection coefficient and phase distribution corresponding to the back-connected RF circuits of different lengths are observed to determine whether it meets the requirements of reflectivity greater than 90% and phase variation range covering 360°. In some embodiments, the frequency band that meets the reflection coefficient and phase distribution requirements may be narrow, and it is necessary to select a suitable operating frequency point based on the actual simulation results.

[0033] According to the abnormal reflection angle of the SCSMS to be designed, the SCSMS reflection phase gradient distribution is determined. In some embodiments, the operating frequency is converted into wavelength, and the gradient phase distribution is determined according to the Snell reflection law.

[0034] The RF circuit length is determined by simulation based on the required phase gradient distribution. In some embodiments, different reflection phases on each unit can be obtained by changing the RF circuit length. The RF circuit length that is as close to the ideal reflection phase as possible is determined through simulation optimization, and an error within 5° is acceptable.

[0035] In a further embodiment, the radio frequency circuit utilizes the localization of guided wave energy transmission to eliminate unnecessary electromagnetic coupling between adjacent units caused by non-periodicity.

[0036] The present invention also provides a SCSMS capable of achieving high-efficiency abnormal reflection at a large deflection angle, comprising: a surface antenna and a radio frequency (RF) circuit, wherein the surface antenna is used to convert spatial incident electromagnetic waves into guided waves, and couple the received incident electromagnetic waves to a back-connected RF circuit for transmission, wherein the RF circuit is used to achieve total reflection and a gradient change of a specific reflection phase, and finally, the guided wave reflection echo is radiated back into free space through the surface antenna.

[0037] The SCSMS includes several SCSMS unit structures, which include: square metal patches, Minkowski fractal patches, floor structures with H-shaped grooves, radio frequency circuits, and all-metal structures arranged in sequence from top to bottom. The square patches and Minkowski fractal patches are both stacked on a RogersRO3003 dielectric substrate. The Minkowski fractal patches are connected to the radio frequency circuit through a floor structure with an H-shaped groove. The radio frequency circuit adopts a stripline structure. The upper and lower metal baselines and the middle phase extension line are separated by a Rogers RO3003 dielectric substrate. An adhesive layer Rogers 4450B is arranged between different dielectric substrates. The all-metal structure is located at the bottom and serves as the upper floor of the stripline radio frequency circuit structure.

[0038] The present invention is described in detail below in conjunction with embodiments and drawings.

[0039] Example

[0040] This embodiment takes the high-efficiency abnormal reflection with a large deflection angle based on SCSMS as an example. The excitation condition is set to a y-polarized plane wave incident from a 20° direction, and the reflection angle is required to be 50°. We will further explain it in detail with reference to the accompanying drawings.

[0041] See also Figure 1 , is a schematic diagram of the SCSMS that utilizes high-efficiency abnormal reflection that can achieve a large deflection angle in this embodiment. The metasurface unit structure includes: a surface antenna, a radio frequency (RF) circuit, and the surface antenna is used to convert the received incident wave into a guided wave and transmit it to the back-connected RF circuit. The RF circuit is used to achieve a gradient change of a specific phase. Finally, the guided wave reflection echo is radiated back to the free space through the surface antenna.

[0042] See also Figure 2 , which is a schematic diagram of the three-dimensional overall structure of using the reflective SCSMS to achieve high-efficiency abnormal reflection with a large deflection angle, and a two-dimensional structure is used to control the phase of the incident spatial electromagnetic wave.

[0043] See also Figure 3 , which is a schematic diagram of a high-efficiency abnormal reflection SCSMS unit structure with a large deflection angle, where (a) is a three-dimensional schematic diagram of the reflective SCSMS unit structure; (b) is a side view of the unit structure; (c) is a top view of the first-layer metal patch structure; (d) is a top view of the second-layer Minkowski fractal structure; (e) is a top view of the third-layer floor structure with an H-shaped groove; and (f) is a top view of the fourth-layer back-connected RF circuit structure. The SCSMS unit structure includes a square metal patch, a Minkowski fractal patch, a floor structure with an H-shaped groove, a radio frequency circuit, and a full metal structure. The square patch and the Minkowski fractal patch are both stacked on a Rogers RO3003 dielectric substrate. The Minkowski fractal patch is connected to the radio frequency circuit through a floor structure with an H-shaped groove. The radio frequency circuit adopts a stripline structure. The upper and lower metal baselines and the middle phase extension line are separated by the Rogers RO3003 dielectric substrate. An adhesive layer Rogers 4450B is provided between different dielectric substrates. The full metal structure is located at the bottom and serves as the upper floor of the stripline radio frequency circuit structure. The Rogers RO3003 dielectric substrate has a dielectric constant of 3, a dielectric loss tangent of 0.001, and a thickness h1 of 0.254 mm. The adhesive layer Rogers 4450B has a dielectric constant of 3.52, a dielectric loss tangent of 0.003, and a height h2 of 0.1 mm.

[0044] See also Figure 4 , which is a simulation diagram of the antenna efficiency of the SCSMS element structure. In this embodiment, the antenna efficiency of the SCSMS unit structure under periodic boundary conditions is simulated and optimized. The transmission efficiency of the electromagnetic wave coupled from the free space to the terminal port when the RF circuit terminal is terminated with a matching port is simulated. As can be seen from the figure, in the range of 19.86GHz-24.92GHz, the coupling transmission efficiency of the surface antenna is higher than -0.5dB, indicating that in this frequency range, the optimized unit structure can couple the free space incident wave to the back-connected circuit with near-perfect efficiency.

[0045] See also Figure 5 , which is the simulation result diagram of the reflective SCSMS element with different back-load circuit lengths. (a) The size of the simulated reflection coefficient varies with the length L of the back-load circuit. (b) The simulated phase of the reflection coefficient varies with the length L of the back-load circuit. We simulated the reflection characteristics of the unit structure when the circuit terminal is open. The reflection coefficient and phase distribution of back-connected RF circuits of different lengths were studied. It can be seen from the figure that at around 21.5GHz, when L changes from 0.5mm to 4.5mm (where L=l1+l2), the reflection coefficient is greater than -0.7dB, and the phase change covers 360°. The simulation results show that the designed reflective SCSMS unit can meet the required abnormal reflection requirements. The optimized structural size parameters are as follows Figure 3 , where h1=0.254mm, h2=0.1mm, p=5mm, a=3.2mm, b1=2.1mm, b2=0.4mm, b3=0.5mm, c1=1.5mm, c2=1.9mm, c3=0.3mm, c4=0.2mm, w1=0.2mm, w2=0.5mm.

[0046] See also Figure 6 , is the overall structural design diagram of the abnormal reflection SCSMS. This embodiment designs a reflective SCSMS composed of 12×12 units to achieve abnormal reflection under y-polarization 20° oblique incidence. In order to achieve abnormal reflection with a reflection angle of 50°, according to the Snell reflection formula: where θ r Indicates the abnormal reflection angle, θ i Represents the incident angle, λ0 represents the wavelength, dφ / dx represents the phase gradient wavelength, and the phase difference between adjacent elements should be 146.26°. The design optimizes 12 basic units (the unit RF circuit sizes are L=0.5mm, L=0.9mm, L=1.1mm, L=1.8mm, L=2.9mm, L=3.1mm, L=3.2mm, L=3.8mm, L=4mm, L=4.4mm, L=4.5mm, L=5.8mm) and forms an array.

[0047] See also Figure 7 , which is a comparison diagram of the reflection phase distribution along the x-axis between the theoretical requirements and the simulation results. It can be seen from the figure that the phase distribution of the designed basic unit is in good agreement with the theoretical requirements, with only slight differences that can be ignored.

[0048] See also Figure 8 , is the RCS simulation result of SCSMS and metal plate at 21.5GHz under y-polarization oblique 20° incidence condition. It can be seen from the figure that the RCS value of the reflective SCSMS reaches a maximum of -4.5dBsm at 50°. Due to mirror reflection, the RCS of the metal plate reaches a maximum of -1.2dBsm at -20°. The reflective SCSMS abnormal reflection efficiency is close to 68%, which is close to the theoretical efficiency upper limit of the conventional phase gradient metasurface method when achieving abnormal reflection at a large rotation angle of 70°, indicating that the proposed method of achieving high-efficiency abnormal reflection with a large deflection angle based on SCSMS is feasible.

Claims

1. A method for realizing high-efficiency abnormal reflection with a large deflection angle based on SCSMS, characterized in that: include: Using surface antennas to receive incident waves and radiate reflected waves; Connecting the surface antenna to the RF circuit; The RF circuit parameters are determined according to the gradient phase distribution of the reflection surface to be designed. The specific method is as follows: According to the required working frequency band, the antenna efficiency of the unit structure under periodic boundary conditions is simulated and optimized to obtain a unit surface antenna structure with an aperture efficiency greater than 90%; Based on the reflection characteristics of the unit structure obtained by simulation when the terminal of the unit RF circuit is open, the reflection coefficient and phase distribution corresponding to the back-connected RF circuits of different lengths are observed to determine whether the reflectivity meets the requirements of greater than 90% and the phase variation range covers 360°. Determine the SCSMS reflection phase gradient distribution according to the required abnormal refraction angle; Determine the length of each basic unit radio frequency circuit according to the required phase gradient distribution and the relationship between the radio frequency circuit length and the phase delay; Use radio frequency circuits to control the characteristics of electromagnetic waves; The SCSMS includes several SCSMS unit structures, which include: square metal patches, Minkowski fractal patches, floor structures with H-shaped grooves, radio frequency circuits, and all-metal structures. The square metal patches and Minkowski fractal patches are stacked on a Rogers RO3003 dielectric substrate. The Minkowski fractal patches are connected to the radio frequency circuit through the floor structure with H-shaped grooves. The radio frequency circuit adopts a stripline structure. The upper and lower metal baselines and the middle phase extension line are separated by the Rogers RO3003 dielectric substrate. An adhesive layer Rogers 4450B is arranged between different dielectric substrates. The all-metal structure is located at the bottom and serves as the upper floor of the stripline radio frequency circuit structure.

2. The method for realizing high-efficiency abnormal reflection with a large deflection angle based on SCSMS according to claim 1, characterized in that: The surface antenna unit structure patterns are consistent in size.

3. The method for realizing high-efficiency abnormal reflection with a large deflection angle based on SCSMS according to claim 1, characterized in that: The Rogers RO3003 dielectric substrate has a dielectric constant of 3, a dielectric loss tangent of 0.001, and a thickness of 0.254 mm.

4. The method for realizing high-efficiency abnormal reflection with a large deflection angle based on SCSMS according to claim 1, characterized in that: The bonding layer Rogers 4450B has a dielectric constant of 3.52, a dielectric loss tangent of 0.003, and a height of 0.1 mm.

5. A SCSMS capable of achieving high-efficiency abnormal reflection at a large deflection angle, characterized in that: include: A surface antenna and a radio frequency circuit, wherein the surface antenna is used to convert the received incident wave into a guided wave and transmit it to the back-connected radio frequency circuit, and the radio frequency circuit is used to realize total reflection and reflection phase gradient change, and transmit the guided wave back to the free space through the surface antenna; the SCSMS comprises a plurality of SCSMS unit structures, and the SCSMS unit structure comprises, arranged in sequence from top to bottom: a square metal patch, a Minkowski fractal patch, a floor structure with an H-shaped groove, a radio frequency circuit, and a full metal structure, wherein the square metal patch and the Minkowski fractal patch are both stacked on a Rogers RO3003 dielectric substrate, and the Minkowski fractal patch is connected to the radio frequency circuit through a floor structure with an H-shaped groove, and the radio frequency circuit adopts a stripline structure, wherein the upper and lower metal base lines and the middle phase extension line are separated by the Rogers RO3003 dielectric substrate, and an adhesive layer Rogers 4450B is arranged between different dielectric substrates, and the full metal structure is located at the bottom as the upper floor of the stripline radio frequency circuit structure.

6. The SCSMS capable of realizing high-efficiency abnormal reflection at a large deflection angle according to claim 5, characterized in that: The Rogers RO3003 dielectric substrate has a dielectric constant of 3, a dielectric loss tangent of 0.001, and a thickness of 0.254 mm.

7. The SCSMS capable of realizing high-efficiency abnormal reflection at a large deflection angle according to claim 5, characterized in that: The bonding layer Rogers 4450B has a dielectric constant of 3.52, a dielectric loss tangent of 0.003, and a height of 0.1 mm.

Images