A low-scattering broadband active coding metasurface and its design method

Abstract

The present invention discloses a low-scattering broadband active coding metasurface and a design method thereof, relating to the technical field of electromagnetic metasurface design. The metasurface comprises a plurality of active reflection / transmission structural units arranged in a rectangular periodic pattern. Each structural unit comprises a rectangular dielectric plate, a double-layer resonant structure arranged on the upper and lower surfaces of the dielectric plate, a bias feed layer arranged in an orthogonal manner in the middle of the dielectric plate, and a metal reflector. The resonant structure comprises two symmetrical upper and lower layers of H-shaped metal patches connected at the center of the H-shaped metal patches by a PIN switch tube. The reflector is spaced a certain distance from the lower surface of the resonant structure. The present invention can simultaneously achieve radar cross-sectional area reduction (the radar cross-sectional area of ​​vertically incident TE-polarized electromagnetic waves within 10.42-12.71GHz is reduced by 7-16dBsm) and phase modulation of the transmitted wave.

Description

Technical Field

[0001] The present invention relates to the technical field of electromagnetic metasurface design, and in particular to a low-scattering broadband active coding metasurface and a design method thereof. Background Art

[0002] Antennas are a crucial component of communications systems. Acting as both transmitters and receivers, they are essential devices used in modern electronic devices to transmit and receive wireless communications signals. Antennas operate by radiating and being radiated radio waves, enabling information to be transmitted across space. The development of antennas can be traced back to the first wire antenna system (dipole-ring resonator) developed by Hertz in the late 19th century. On the eve of World War II, the advent of microwave klystrons and magnetrons led to the emergence of microwave radar, and centimeter-wave antennas became commonplace. Planar antennas saw significant development in the early 1930s, with the emergence of dielectric resonant antennas, slot antennas, and helical antennas. Antenna systems also transitioned from single antennas to multi-antenna arrays. Single antenna systems are limited by their wide beamwidth, low gain, and poor flexibility, making them inadequate for civilian base stations and military radars. Phased array technology has become a mainstream development in recent years, attracting significant attention. Phased array technology involves adjusting the phase of radiation from radiating elements through circuits to achieve spatial coherence and beam redirection. Phased array antenna systems offer narrow beamwidth, high gain, and enhanced scanning flexibility. However, traditional phased array systems, in addition to the antenna as a radiator, also include subsequent RF circuits such as attenuators, power splitters, and phase shifters, resulting in high complexity and cost. Metasurface technology, a recent emerging technology, achieves beam scanning by adjusting the phase and amplitude of transmitted / reflected waves. It offers advantages such as ease of deployment, low cost, low energy consumption, and programmability.

[0003] Antenna systems are ubiquitous in modern equipment systems, including navigation, radar, communications, telemetry, and electronic reconnaissance and countermeasure systems. As strong scattering sources, in the era of electronic warfare, antenna platforms on vehicles, aircraft, and ships not only require high radiation characteristics, but also rely on their scattering performance, measured by radar cross-section (RCS), to determine their wartime survivability. Low RCS antenna systems have become a research hotspot worldwide. In recent years, extensive research has been conducted on low-scattering phased array antenna platforms using radiation phase control technology, as summarized below:

[0004] Passive RCS reduction technologies for array antennas primarily include resistive absorber reduction technology and checkerboard surface reduction technology. Resistive absorber reduction technology achieves RCS reduction by designing a frequency selective surface and loading it with resistive elements, which absorb the current coupled to the frequency selective surface. Checkerboard surface reduction technology rotates a diagonally symmetrical frequency selective surface structure 90° clockwise or counterclockwise to form four units with opposite reflection phases. These units are placed around the antenna, canceling out the phases at perpendicular incidence of electromagnetic waves, thereby achieving RCS reduction. However, both of these methods require external phase control circuits, such as CNC phase shifters, to control the phase of the radiated wave to achieve RCS reduction.

[0005] Active RCS reduction technology for array antennas involves attaching active devices to the radiator or antenna carrier platform to modulate the phase of the reflected wave, making it spatially coherent and reducing RCS. For example, resonant rings are placed around the array antenna and loaded with varactor diodes to achieve phase control of the reflected wave and complete RCS reduction. This method achieves RCS reduction by controlling the phase of the reflected wave, but the integrated antenna RCS reduction and radiation phase control mentioned above remain unrealized.

[0006] In summary, the problem of integrating antenna RCS reduction and radiation phase control needs to be solved urgently. Summary of the Invention

[0007] In view of this, the present invention provides a low-scattering broadband active coding metasurface and a design method thereof. The designed active coding metasurface can realize the integration of antenna RCS reduction and radiation phase control. The design method of the metasurface can design a low-scattering broadband active coding metasurface that meets the functional requirements of incident wave scattering and radiation wave phase control and can achieve RCS reduction.

[0008] To achieve the above objectives, the technical solution of the present invention is: a low-scattering broadband active coding metasurface, comprising a plurality of structural units arranged in a rectangular periodic pattern, each structural unit comprising a rectangular dielectric plate, a first resonant structure, a second resonant structure, a bias feed layer, and a metal reflector.

[0009] The first resonant structure and the second resonant structure are respectively arranged on the upper and lower surfaces of the rectangular dielectric plate; the first resonant structure and the second resonant structure are both H-shaped metal patches, which are symmetrically arranged on the upper and lower surfaces of the rectangular dielectric plate and connected by a switch PIN switch tube at the center of the two H-shaped metal patches.

[0010] The bias feeding layer is arranged at the middle position of the rectangular dielectric plate.

[0011] The metal reflector is arranged under the second resonant structure, and the two are separated by a set distance.

[0012] Preferably, the low-scattering broadband active coding metasurface is used to achieve an RCS reduction of 7-16 dBsm for vertically incident TE polarized waves in the operating frequency band of 10.42-12.71 GHz.

[0013] Preferably, the current conduction direction of the PIN switch tube is selected as the x direction, and the direction perpendicular to the x direction is the y direction; wherein, as a mirror-symmetrical structure along the y direction, the length of a single arm of a single H-shaped metal patch along the y direction is l1, and the width is w1; the centers of the two y-direction arms are both provided with a choke slot along the x direction, and the long side of the choke slot is along the x direction, and the length is also w1, and the width is w s The cross arm length of the H-shaped metal patch along the x-direction is l2, and the width is w2. The gap between the PIN switch pads is located in the center of the H-shaped metal patch and distributed along the y-direction with a spacing of w. gap .

[0014] Preferably, the rectangular dielectric plate is made of Taconic TLX-8 material with a thickness of h sub , the period interval is w sub , the dielectric constant is 2.55, and the loss tangent is 0.0017.

[0015] Preferably, the distance between the metal reflective plate and the lower surface of the second resonant structure is h.

[0016] Preferably, the metal reflective plate is made of copper.

[0017] Another embodiment of the present invention further provides a method for designing a low-scattering broadband active coding metasurface, comprising the following steps:

[0018] Step 1: Based on a low-scattering broadband active coding metasurface structure as claimed in claim 1, a metasurface model is established; wherein the sizes of the first resonant structure and the second resonant structure are designed as follows.

[0019] Determine the center operating frequency f, and according to the center operating frequency f and the parameters of the rectangular dielectric plate, determine the effective resonant structure length W according to formulas (1) and (2), where the parameters of the rectangular dielectric plate include the relative dielectric constant ε of the rectangular dielectric plate. r , the equivalent dielectric constant ε of the rectangular dielectric plate e and the thickness h of the rectangular dielectric plate sub ;

[0020]

[0021]

[0022] Where c is the propagation speed of light in vacuum, and W is the effective resonant structure length.

[0023] After determining the effective resonant structure length W, the dimensions of the first resonant structure and the second resonant structure are set to satisfy formula (3):

[0024] W=l1-w2+2l2 (3)

[0025] The current conduction direction of the PIN switch tube is selected as the x direction, and the direction perpendicular to the x direction is the y direction. The length of a single arm of a single H-shaped metal patch along the y direction is l1, and the width is w1; the length of the horizontal arm of the H-shaped metal patch distributed along the x direction is l2, and the width is w2; that is, the dimensions of the designed first resonant structure and the second resonant structure include l1, w2, and l2.

[0026] Step 2: Using the metasurface model designed in step 1, the incident wave passes through the resonant structure twice in succession, and the phase difference of the single-pass transmission wave in the resonant structure in the transmission state is deduced. like If formula (4) is satisfied, the sizes of the designed first resonant structure and the second resonant structure are the final desired sizes. Otherwise, return to step 1 and redesign until the final desired sizes are obtained.

[0027]

[0028] in, and They are the reflection phases of the PIN switch tube in the off state 1 and the on state 0 respectively.

[0029] Beneficial effects:

[0030] 1. The present invention provides a low-scattering, broadband, active coding metasurface. Its specific components include a rectangular dielectric plate, a double-layer resonant structure disposed on the upper and lower surfaces of the dielectric plate, and a metal reflector. When an external TE-polarized incident wave enters and passes through the metasurface's resonant structure, the reflected wave is totally reflected by the reflector, then passes through the resonant structure again and radiates into free space. Through targeted design, the metasurface also has the function of phase modulating the radiated wave. Compared to traditional antennas that use phase shifters and other subsequent microwave circuits to achieve phase modulation, the present invention achieves an integrated design that combines RCS reduction with radiation phase control.

[0031] 2. The present invention provides a design method for a low-scattering broadband active coding metasurface. Based on the operating frequency of the metasurface, the specific structure and dimensions of the phase modulation surface and the reflective surface are designed. The effective length of the phase modulation surface resonant structure is calculated using the center operating frequency, and the physical dimensions of the H-shaped resonant structure are then determined. According to the design results, the low-scattering broadband active coding reflective / transmissive metasurface can achieve phase control of the radiated wave and achieve an RCS reduction of 7-16dBsm for vertically incident TE polarized waves in the operating frequency band of 10.42-12.71GHz. Compared with existing technologies, this technology realizes the integrated design of radiation phase modulation and RCS reduction within a wide bandwidth. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 (a), (b), and (c) are schematic diagrams of the structure, size, and working principle of the low-scattering broadband active coding reflection / transmission metasurface unit.

[0033] Figure 2 Schematic diagram of the structure of the low-scattering broadband active coded reflection / transmission metasurface transmission phase shifting unit.

[0034] Figure 3 These are the amplitude and phase curves of the transmitted wave of the low-scattering broadband active coded reflection / transmission metasurface transmission phase-shifting unit when the PIN switch tube is in the ON / OFF state.

[0035] Figure 4 The reflected wave amplitude and phase curves of the low-scattering broadband active coding reflection / transmission metasurface when the PIN switch tube is in the ON / OFF state.

[0036] Figure 5 Schematic diagram of low-scattering broadband active coding reflection / transmission metasurface PIN switch tube encoding.

[0037] Figure 6 This is a comparison chart of the radar scattering cross-section results of low-scattering broadband active coded reflection / transmission metasurface. DETAILED DESCRIPTION

[0038] The present invention is described in detail below with reference to the accompanying drawings and embodiments.

[0039] The present invention provides a low-scattering broadband active coding metasurface, such as Figure 1 As shown, it includes a plurality of structural units arranged in a rectangular periodic pattern, each structural unit including a rectangular dielectric plate, a first resonant structure, a second resonant structure, a bias feed layer and a metal reflective plate;

[0040] The first resonant structure and the second resonant structure are respectively arranged on the upper and lower surfaces of the rectangular dielectric plate; the first resonant structure and the second resonant structure are both H-shaped metal patches, which are symmetrically arranged on the upper and lower surfaces of the rectangular dielectric plate and connected by a switch PIN switch tube at the center of the two H-shaped metal patches.

[0041] The bias feeding layer is arranged at the middle position of the rectangular dielectric plate.

[0042] The metal reflector is arranged under the second resonant structure, and the two are separated by a set distance.

[0043] The current conduction direction of the PIN switch tube is selected as the x direction, and the direction perpendicular to the x direction is the y direction;

[0044] Among them, as a mirror-symmetrical structure along the y direction, the length of a single arm of a single H-shaped metal patch along the y direction is l1 and the width is w1; the centers of the two y-direction arms are both provided with a choke slot along the x direction, and the long side of the choke slot is along the x direction, with a length of w1 and a width of w. s The cross arm length of the H-shaped metal patch along the x-direction is l2, and the width is w2. The gap between the PIN switch pads is located in the center of the H-shaped metal patch and distributed along the y-direction with a spacing of w. gap The rectangular dielectric plate is made of Taconic TLX-8 material with a thickness of h sub , the period interval is w sub , the dielectric constant is 2.55, and the loss tangent is 0.0017.

[0045] The design method for the low-scattering broadband active coding metasurface includes the following steps:

[0046] Step 1: Establish a metasurface model according to a low-scattering broadband active coding metasurface structure as claimed in claim 1; wherein the dimensions of the first resonant structure and the second resonant structure are designed as follows:

[0047] Determine the center operating frequency f, and according to the center operating frequency f and the parameters of the rectangular dielectric plate, determine the effective resonant structure length W according to formulas (1) and (2), where the parameters of the rectangular dielectric plate include the relative dielectric constant ε of the rectangular dielectric plate. r , the equivalent dielectric constant ε of the rectangular dielectric plate e and the thickness h of the rectangular dielectric plate sub ;

[0048]

[0049]

[0050] Where c is the propagation speed of light in vacuum, W is the effective resonant structure length;

[0051] After determining the effective resonant structure length W, the dimensions of the first resonant structure and the second resonant structure are set to satisfy formula (3):

[0052] W=l1-w2+2l2 (3)

[0053] The current conduction direction of the PIN switch tube is selected as the x direction, and the direction perpendicular to the x direction is the y direction. The length of a single arm of a single H-shaped metal patch along the y direction is l1, and the width is w1; the length of the cross arm of the H-shaped metal patch distributed along the x direction is l2, and the width is w2. That is, the dimensions of the designed first resonant structure and the second resonant structure include l1, w2, and l2;

[0054] Step 2: Using the metasurface model designed in step 1, the incident wave passes through the resonant structure twice in succession, and the phase difference Δφ of the single-pass transmission wave of the resonant structure in the transmission state is deduced. If Δφ satisfies formula (4), the dimensions of the designed first resonant structure and the second resonant structure are the final desired dimensions. Otherwise, return to step 1 and redesign until the final desired dimensions are obtained.

[0055] Δφ=(φ_0-φ_1) / 2=π / 2 (4)

[0056] Among them, φ_0 and φ_1 are the reflection phases of the PIN switch tube in the off state 1 and the on state 0 respectively.

[0057] Example 1:

[0058] The embodiment of the present invention proposes a low-scattering broadband active coding metasurface, such as Figure 1 As shown in (a), the specific components include: a rectangular dielectric plate, a double-layer resonant structure arranged on the upper and lower surfaces of the dielectric plate, and a metal reflector.

[0059] like Figure 1 As shown in (b), the resonant structure includes two symmetrical upper and lower layers of identical H-shaped metal patches, which are connected at the center of the two H-shaped metal patches by a PIN switch tube.

[0060] In one embodiment of the present invention, the super surface unit is a rectangle, and one side is selected as the x direction, and the other side perpendicular to it is selected as the y direction, and the length of both sides is w. sub =12mm, the thickness of the upper and lower double layers is h sub =1.57mm. Among them, the short side of the H-shaped resonant structure is distributed along the y direction, with a length of l1 = 8mm and a width of w1 = 2.4mm. The long side of the choke slot is distributed along the x direction, with a length of w1 = 2.4mm and a width of w s =0.3mm; the long side coverage is distributed along the x direction, with a length of l3 = 8.6mm. The PIN switch tube pad gap is located in the center of the H-shaped metal patch and distributed along the y direction with a spacing of wgap = 0.3mm, and length w2 = 1.6mm. The equivalent circuit parameters for the switch embedded in the center of the resonant structure in the on-state are R = 7.8Ω, L = 30pH; in the off-state, the equivalent circuit parameters are L = 30pH, and C = 0.025pF. The distance between the reflector and the underlying resonant structure is h = 2.4mm, and the distance between the underlying metal floor and the dielectric layer is h = 2.4mm.

[0061] In one embodiment of the present invention, the dielectric constant of the dielectric plate is 2.55, the metal patch, the feed line, and the metal layer are made of copper, and the model of the PIN switch tube is MADP-000907-14020x.

[0062] Example 2:

[0063] Figure 3 The design principle of the proposed low-scattering electromagnetic metasurface is described in detail. When the external TE polarized incident wave (indicated by the blue arrow) is incident and passes through the metasurface resonant structure, the reflected wave will be totally reflected by the reflector, and then pass through the resonant structure again and radiate into the free space. In order to achieve the low-scattering characteristics of the metasurface, the metasurface unit must meet the following two conditions: First, the far-field phase of the electromagnetic wave reflected back to the free space by the metasurface unit must achieve two coding states of 0 and π, that is, the phase difference between the two states is π; Second, the metasurface units in the two coding states are distributed in a checkerboard pattern, such as Figure 5 At the same time, the radiation waves of the radiator can also be phase modulated by the metasurface unit.

[0064] First, the central operating frequency is determined to be approximately 11.5 GHz, f. Since the size of the metasurface unit resonant structure is determined by the operating frequency and the dielectric plate parameters:

[0065]

[0066]

[0067] Where c is the speed of light in vacuum, f is the central operating frequency, and ε r is the relative dielectric constant of the dielectric layer, ε e is the equivalent dielectric constant of the dielectric layer, h sub is the thickness of the dielectric layer, W is the effective resonant structure length (current flows through) in the present invention, and Figure 1 The dimensions marked in (b) have the following relationship:

[0068] W=l1-w2+2l2 (3)

[0069] In order to ensure that the TE polarized incident wave within the operating frequency can completely pass through the resonant structure, a choke slot along the x-axis is required to cut off the cross-polarized induced current generated along the y-axis, thereby ensuring a stable and consistent induced current path.

[0070] After analysis, the incident wave will pass through the resonant structure twice in succession. It can be deduced that the phase difference of the single-pass transmission wave in the resonant structure is The conditions are:

[0071]

[0072] in, and They are the reflection phases of the PIN switch in the off (OFF) state 1 and the on (ON) state 0 respectively. The resonant structure is as follows Figure 2 As shown, the above structure size determines the operating frequency of the present invention, while the resonant structure double-sided PIN switch is responsible for the modulation of the transmission phase. Figure 3 As shown in the figure, it can be obtained that the main polarization transmittance within the working frequency band can be stably maintained above -3dB, and at the same time, the transmission phase difference of the metasurface corresponding to the coding state when the switch tube is in the ON / OFF (0 / 1) state is within After adding the reflector, the amplitude and phase of the reflected wave are as follows: Figure 4 As shown: It is not difficult to see that within the working frequency band, when the switch tube state is in the ON / OFF (0 / 1) state, the corresponding coding state reflection phase difference is close to π, and the result is consistent with the principle design.

[0073] like Figure 5 As shown in FIG, the proposed metasurface units are arranged in a chessboard shape and excited by a vertically incident TE polarized wave. The distribution of the PEC metal plate and the metasurface (all ON or OFF) of the same size is compared. The radar cross-sectional area is shown in FIG (6): For the PEC metal plate of the same size, the radar cross-sectional area reaches the maximum when the incident wave is fully reflected; the radar cross-sectional area of ​​the metasurface in the full ON and full OFF states is slightly reduced due to a small amount of insertion loss; and the proposed low-scattering metasurface achieves a radar cross-sectional area reduction of 7-16dBsm in the 10.42-12.71GHz operating frequency band, and the relative operating bandwidth reaches 20%. At the same time, the metasurface proposed in the present invention also has the following advantages: Figure 1 Compared with the traditional antenna which uses phase shifters and other subsequent microwave circuits to achieve phase modulation, the present invention realizes an integrated design that combines stealth and radiation phase control functions.

[0074] For a low-scattering broadband active coding metasurface provided in any of the above embodiments, the present invention provides a targeted design method, the principle of which is: determine the function and working principle of the metasurface. For external incident waves on the metasurface, the metasurface needs to realize the regulation of its scattering, so as to achieve the characteristics of low scattering; for the radiation waves inside the metasurface, the metasurface needs to realize the phase regulation of the transmitted waves. Through analysis, the designed metasurface should have two parts: a phase modulation surface (resonant structure) and a reflective surface (metal reflector). For the phase modulation surface, it is necessary to realize the modulation of the transmitted (incident and radiation) waves; for the reflective surface, it is necessary to cooperate with the phase modulation surface to realize the scattering characteristics of the external incident waves on the metasurface.

[0075] The steps of this design method are:

[0076] S1: Based on the operating frequency of the metasurface, the specific structure and dimensions of the phase modulation surface and reflective surface are designed. The limited spacing between the metasurface's periodic units dictates that the resonant structure of the phase modulation surface cannot be arranged completely in a straight line. Therefore, this invention uses an H-shaped resonant structure and adds choke slots to control the surface current of the resonant structure. The effective length of the phase modulation surface resonant structure is calculated using the center operating frequency, which in turn determines the physical dimensions of the H-shaped resonant structure.

[0077] S2: Add PIN switches to complete the design of the phase modulation metasurface. Based on the dimensions of the metasurface resonant structure calculated and analyzed in the previous steps, a model is built and switches are added. The active PIN switches are used to implement phase modulation. Finally, the entire phase modulation metasurface is simulated and optimized to meet the principle's requirements for incident wave scattering and radiated wave phase control.

[0078] According to the principle of low-scattering control of incident waves, the phase modulation surface is arranged in a 01 (ON / OFF) state chessboard and reflectors are added to complete the final invention design.

[0079] In this embodiment, the performance of the low-scattering metasurface finally designed is as follows:

[0080] The structure of the embodiment of the present invention can achieve a reduction of the radar cross-section by 7-16 dBsm and control the radiation phase in the 10.42-12.71 GHz frequency band with a relative bandwidth of 20% when the TE polarized wave is vertically incident.

[0081] In summary, the above are only preferred embodiments of the present invention and are not intended to limit the scope of protection of the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A low-scattering broadband active coding metasurface, characterized in that: When TE polarized waves are incident vertically, this structure can reduce the radar cross-section by 7-16dBsm in the 10.42-12.71GHz frequency band with a relative bandwidth of 20%, and can also regulate the radiation phase. The metasurface includes a plurality of structural units arranged in a rectangular periodic pattern, each structural unit including a rectangular dielectric plate, a first resonant structure, a second resonant structure, a bias feed layer, and a metal reflector. The first resonant structure and the second resonant structure are respectively arranged on the upper and lower surfaces of the rectangular dielectric plate; the first resonant structure and the second resonant structure are both H-shaped metal patches, which are symmetrically arranged on the upper and lower surfaces of the rectangular dielectric plate and connected by a PIN switch tube at the center of the two H-shaped metal patches; The bias feed layer is arranged at the middle position of the rectangular dielectric plate; The metal reflector is arranged below the second resonant structure, and the two are separated by a set distance; The current conduction direction of the PIN switch tube is selected as the x direction, and the direction perpendicular to the x direction is the y direction; Among them, as a mirror-symmetrical structure along the y direction, the length of a single arm of a single H-shaped metal patch along the y direction is l1 and the width is w1; the centers of the two y-direction arms are both provided with a choke slot along the x direction, and the long side of the choke slot is along the x direction, with a length of w1 and a width of w. s The cross arm length of the H-shaped metal patch along the x-direction is l2, and the width is w2. The gap between the PIN switch pads is located in the center of the H-shaped metal patch and distributed along the y-direction with a spacing of w. gap ; The rectangular dielectric plate is made of Taconic TLX-8 material and has a thickness of h sub , the period interval is w sub , the dielectric constant is 2.55, and the loss tangent is 0.0017; When the external TE polarized incident wave enters and passes through the metasurface resonant structure, the reflected wave will be totally reflected by the reflector, and then pass through the resonant structure again and radiate into the free space.

2. The low-scattering broadband active coding metasurface according to claim 1, wherein: The distance between the metal reflective plate and the lower surface of the second resonant structure is h.

3. A low-scattering broadband active coding metasurface according to claim 1 or 2, characterized in that: The material of the metal reflector is copper.

4. A design method for a low-scattering broadband active coding metasurface, characterized in that: The following steps are involved: Step 1: Establish a metasurface model according to the low-scattering broadband active coding metasurface structure according to claim 1; wherein the dimensions of the first resonant structure and the second resonant structure are designed as follows: Determine the center operating frequency f, and determine the effective resonant structure length W according to the center operating frequency f and the parameters of the rectangular dielectric plate according to formulas (1) and (2), wherein the parameters of the rectangular dielectric plate include the relative dielectric constant ε of the rectangular dielectric plate. r , the equivalent dielectric constant ε of the rectangular dielectric plate e and the thickness h of the rectangular dielectric plate sub ; Where c is the propagation speed of light in vacuum, W is the effective resonant structure length; After determining the effective resonant structure length W, the dimensions of the first resonant structure and the second resonant structure are set to satisfy formula (3): W=l1-w2+2l2 (3) The current conduction direction of the PIN switch tube is selected as the x direction, and the direction perpendicular to the x direction is the y direction. The length of a single arm of a single H-shaped metal patch along the y direction is l1, and the width is w1; the length of the cross arm of the H-shaped metal patch distributed along the x direction is l2, and the width is w2. That is, the dimensions of the designed first resonant structure and the second resonant structure include l1, w2, and l2; Step 2: Using the metasurface model designed in step 1, the incident wave passes through the resonant structure twice in succession, and the phase difference of the single-pass transmission wave in the resonant structure in the transmission state is deduced. like If formula (4) is satisfied, the sizes of the designed first resonant structure and the second resonant structure are the final desired sizes. Otherwise, return to step 1 and redesign until the final desired sizes are obtained. in, and They are the reflection phases of the PIN switch tube in the off state 1 and the on state 0 respectively.

Images