A broadband multifunctional reconfigurable electromagnetic metasurface

Abstract

The present invention discloses a broadband multifunctional reconfigurable electromagnetic metasurface, which includes a polarization twist layer, a resistance loss layer, and a reconfigurable frequency selection layer; by loading a spiral inductor, the construction of a wide stopband in the mid-frequency band can be realized, and the lower floor is replaced with a reconfigurable gradient trapezoidal frequency selection surface. The switching of the transmission and reflection in the mid-frequency band can be realized by the switch of the PIN tube. On this basis, the equivalent circuit characterization and multi-parameter collaborative design method are used to adjust the interlayer height to realize the construction of the high-frequency stopband; the introduction of the polarization twist layer can realize the high-frequency polarization twist function, and the polarization phase cancellation can be used to realize the diffuse scattering function. The present invention can expand the adaptability and survivability of the application scenarios of traditional electromagnetic equipment, and has important academic value and application prospects in the fields of information security, anti-electromagnetic interference, radar antenna cover, electromagnetic information and system confrontation.

Description

Technical Field

[0001] The present invention belongs to the technical field of electromagnetic metamaterials, and in particular to a broadband multifunctional reconfigurable electromagnetic metasurface. Background Art

[0002] In view of the functional applications of electromagnetic metasurfaces in electronic reconnaissance, wireless communication, anti-interference, airspace stealth and other scenarios, in order to achieve fine control of electromagnetic waves in the frequency domain, airspace, polarization domain and energy domain, and improve the performance of independent equipment and the comprehensive working ability of multiple equipment, new design requirements such as high integration, ultra-wideband, low profile and multi-function are proposed for electromagnetic metasurfaces. Traditional metasurfaces have independent functions such as wave absorption, polarization twisting and wave transmission. Although the working bandwidth of such metasurfaces is relatively wide, they have single functions and low integration, making it difficult to meet the requirements of multi-function and reconfigurable design.

[0003] With the increasing complexity of the electromagnetic environment in space and the diverse needs of practical engineering applications, the research on electromagnetic metasurfaces with multifunctional characteristics and the combination of metasurfaces and antennas to improve antenna performance has very important practical significance. In particular, active metasurfaces can change the operating frequency or transmission and reflection characteristics by loading external excitations, thereby realizing flexible control of electromagnetic waves, which can be applied to the reconfigurable design of antennas. On the other hand, reconfigurable metasurfaces have attracted widespread attention because they can receive or transmit signals at specific frequencies and absorb or reflect incoming waves from any direction in a certain frequency band. Summary of the invention

[0004] The purpose of the present invention is to provide a broadband multifunctional reconfigurable electromagnetic metasurface with multiple functions for achieving fine control of electromagnetic waves, which can be mass-produced using printed circuit technology and has the advantages of small size, stable performance and low production cost.

[0005] The technical solution to achieve the purpose of the present invention is: a broadband multifunctional reconfigurable electromagnetic metasurface, comprising an upper polarization twisting layer, a middle resistive loss layer, and a lower reconfigurable frequency selective surface layer;

[0006] The polarization twisting layer is loaded with centrally symmetrical arrow-shaped metal patches, which are centrally symmetrical and distributed at the diagonal edges of the surface layer; the front side of the resistance loss layer is eight packaged resistors and square metal strips, the packaged resistors are located at the edges of the front side of the resistance loss layer and are connected by metal strips, and the back side is four spiral inductors, which are located in the center of each side of the resistance loss layer and are connected by metal vias; the reconfigurable frequency selective surface is divided into five layers from top to bottom, namely: gradient trapezoidal metal patches and PIN diodes, dielectric substrates, strip metal patches, dielectric substrates, and square metal patches, wherein the PIN diode is located in the center of the reconfigurable frequency selective surface and is connected to two gradient trapezoidal metal patches, which are welded by PCB technology, and the strip metal patches and square metal patches are printed on the dielectric substrate, and the five-layer structure is pressed together by PCB technology.

[0007] Furthermore, the polarization twisted layer plate material is composed of a single layer of 0.127 mm thick Rogers RT / duroid5880, a microwave substrate with a dielectric constant of 2.2, and metal copper.

[0008] Furthermore, the resistance loss layer is composed of a 0402 package resistor, a 1.57 mm thick Rogers RT / duroid5880, a microwave substrate with a dielectric constant of 2.2, and metal copper.

[0009] Furthermore, the reconfigurable frequency selective surface is composed of a SMP1345-040LF model PIN diode, FR-4_epoxy, a microwave substrate with a dielectric constant of 4.4, and metal copper.

[0010] Furthermore, the material of all metal patches is copper.

[0011] Compared with the prior art, the present invention has the following significant advantages: (1) The existing metasurface multifunctional designs are mostly limited to 2-3 types, and the introduction of active adjustable electronic devices further limits the broadband performance of the metasurface structure, and the multifunctional design mostly adopts a multi-layer cascade design, which leads to an increase in the profile height. The metasurface in this design innovatively uses only 3 layers of structure to achieve the design of 7 functions such as wave absorption, wave transmission, polarization twisting, reflection, frequency selection, anti-reflection, and diffuse scattering, and the bandwidth of each function meets the requirement of more than 20%. (2) The introduction of active adjustable devices will increase the insertion loss between the metasurface unit layers, and the insertion loss will further affect the wave transmission coefficient of the metasurface structure and affect the integration of functions. The multi-layer metasurface structure of this design has an insertion loss of only 0.245dB, and the 3dB insertion loss bandwidth is 40%, which effectively improves the transmission performance. (3) Compared with the existing multifunctional metasurfaces, the metasurface of this design also has the diffuse scattering function after array formation. It can use the wave absorption, polarization twisting and diffuse scattering functions in the original structure to perform low diffuse scattering fusion collaborative design, and can serve in the new generation of ground combat vehicles, shipborne, and airborne ultra-wideband array radars in electromagnetic spectrum warfare, and improve the wide-band and wide-spatial low-scattering stealth performance of the broadband tightly coupled array. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] The present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0013] Figure 1 It is an overall structural diagram of the multifunctional reconfigurable electromagnetic metasurface unit of the present invention.

[0014] Figure 2 It is a schematic diagram of the polarization twisting layer of the multifunctional reconfigurable electromagnetic metasurface unit of the present invention.

[0015] Figure 3 It is a schematic diagram of the resistance loss layer of the multifunctional reconfigurable electromagnetic metasurface unit of the present invention.

[0016] Figure 4 It is a schematic diagram of the reconfigurable frequency selection layer of the multifunctional reconfigurable electromagnetic metasurface unit of the present invention.

[0017] Figure 5 It is the S parameter of the multifunctional reconfigurable electromagnetic metasurface unit of the present invention when the PIN diode is in the OFF state.

[0018] Figure 6 It is the S parameter of the multifunctional reconfigurable electromagnetic metasurface unit of the present invention when the PIN diode is in the ON state.

[0019] Figure 7 This is a graph of the reflection Rxx and reflection Ryx results of the multifunctional reconfigurable electromagnetic metasurface unit of the present invention under a single-polarized incident wave.

[0020] Figure 8It is a diagram of the actual phase value and difference result between the "0" unit and the "1" unit of the multifunctional reconfigurable electromagnetic metasurface of the present invention.

[0021] Fig. 9 It is a schematic diagram of a metasurface array in which the "0" unit and the "1" unit of the multifunctional reconfigurable electromagnetic metasurface of the present invention each form a 5×5 sub-array, and the sub-arrays form a checkerboard-arranged metasurface.

[0022] Fig.10 This is a comparison diagram of the RCS results of the multifunctional reconfigurable electromagnetic metasurface array of the present invention and the metal floor of equal aperture under TE / TM polarization.

[0023] Fig.11 It is a dual-station RCS reduction curve diagram under different incident angles when the multifunctional reconfigurable electromagnetic metasurface array of the present invention is in the ON state.

[0024] Fig.12 This is a physical picture of the multifunctional reconfigurable electromagnetic metasurface array processing prototype of the present invention. DETAILED DESCRIPTION

[0025] The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

[0026] Combination Figure 1 The present invention proposes an ultra-wideband reconfigurable multifunctional electromagnetic metasurface that has multiple functions such as wave absorption, wave transmission, reflection, and diffuse scattering. Figure 1 As shown, the overall structure is divided into three layers, including an upper polarization twist layer 1, a middle resistance loss layer 2, and a lower reconfigurable frequency selective surface layer 3.

[0027] The polarization twist layer 1 is loaded with a centrally symmetrical "arrow"-shaped metal patch 4; the resistance loss layer 2 has eight 0402 package resistors 5 and a square metal strip 6 on the front, and four spiral inductors 7 on the back; the reconfigurable frequency selective surface 3 is divided into five layers from top to bottom, which are: a gradient trapezoidal metal patch 8 and a PIN diode 9, a dielectric substrate, a strip metal patch 10, a dielectric substrate, and a square metal patch 11. The five-layer structure is laminated by PCB technology.

[0028] The loss layer is loaded with spiral inductors and resistors on the basis of the traditional square ring structure to achieve a wide stopband of 40% in the mid-frequency band, and the relative bandwidth of low-frequency absorption is expanded from 88% to 112%. In order to effectively utilize the wide stopband generated in the mid-frequency band, a more functional design is introduced. The metal floor under the loss layer is removed, and a new layer of reconfigurable gradient trapezoidal frequency selective surface is introduced. The fast switching of the transmission and reflection functions in the mid-frequency band is achieved through the switch control of the PIN tube. The inter-layer height is adjusted to optimize the bandwidth of the low-frequency band and construct a wide stopband in the high-frequency band in the OFF state while taking into account the low-frequency absorption and mid-frequency reflection performance in the ON state. Utilize the wide stopband constructed in the high-frequency band and introduce a polarization twist layer to achieve the function of 22% bandwidth polarization conversion. The unit size is 30*30mm 2 The overall thickness is 42.35mm (0.133λ L ,λ L is the wavelength corresponding to the lowest frequency in the working frequency band).

[0029] The present invention can realize the construction of a wide stopband in the mid-frequency band by loading a spiral inductor. In order to introduce more functional construction, the lower floor is replaced by a reconfigurable gradient trapezoidal frequency selection surface. The switching of the mid-frequency band transmission and reflection can be realized by the switch of the PIN tube. On this basis, the equivalent circuit characterization and multi-parameter collaborative design method are used to adjust the interlayer height to realize the construction of a high-frequency stopband. The introduction of a polarization twist layer can realize the polarization twist function in the high-frequency band, and the polarization phase cancellation can be used to realize the diffuse scattering function. The present invention can expand the adaptability and survivability of traditional electromagnetic equipment application scenarios, and has important academic value and application prospects in the fields of information security, anti-electromagnetic interference, radar antenna cover, electromagnetic information and system confrontation. Further exploration of the comprehensive design scheme of broadband active absorbing materials can meet the urgent needs of intelligent techniques and tactics in various complex electromagnetic environments.

[0030] The metasurface of the present invention innovatively realizes the design of seven functions, namely, wave absorption, wave transmission, polarization twisting, reflection, frequency selection, anti-reflection, and diffuse scattering, by using only three layers of structure, and the bandwidth of each function meets more than 20%.

[0031] Example

[0032] Combination Figure 1 to Figure 4The broadband reconfigurable multifunctional electromagnetic metasurface of the present invention has a low diffuse scattering operating frequency of 0.5 to 8 GHz. Its overall structure is divided into three layers, including an upper polarization twisting layer 1, a middle resistance loss layer 2, and a lower reconfigurable frequency selective surface layer 3. The polarization layer has polarization twisting and diffuse scattering functions, a thickness of 0.127 mm, i.e., 0.0022 wavelengths, and an operating frequency range of 5.24-6.54 GHz; the loss layer has an absorbing function, a thickness of 1.57 mm, i.e., 0.005 wavelengths, and an operating frequency range of 0.94-3.35 GHz; the reconfigurable frequency selective layer has transmission, reflection, and reconfigurable functions, a thickness of 3.7 mm, i.e., 0.018 wavelengths, and an operating frequency range of 3.35-5.05 GHz. The polarization twist layer (1) uses a single layer of 0.127 mm thick Rogers RT / duroid5880 microwave substrate with a dielectric constant of 2.2, on which a centrally symmetrical "arrow" shaped metal patch (4) is loaded; the resistance loss layer (2) uses a 1.57 mm thick Rogers RT / duroid 5880 microwave substrate with a dielectric constant of 2.2, with eight 0402 package resistors (5) and square metal strips (6) on the front side and four spiral inductors (7) on the back side; the reconfigurable frequency selective surface 3 uses FR-4_epoxy, a microwave substrate with a dielectric constant of 4.4, with an overall thickness of 3.7 mm, and is divided into five layers from top to bottom, namely: a gradient trapezoidal metal patch 8 and a PIN diode 9, a dielectric substrate, a strip metal patch 10, a dielectric substrate, and a square metal patch 11. The five-layer structure is laminated by PCB technology. The resistor model used in the resistance loss layer is a 0402 package resistor with a resistance value of 180 ohms, and the PIN diode model used in the reconfigurable frequency selection layer is SMP1345-040LF. The layers are separated by air, and the overall height is 42.35 mm.

[0033] Figure 5 It is the S parameter of the multifunctional reconfigurable electromagnetic metasurface unit of the present invention when the PIN diode is in the OFF state. It can be seen that the S21 parameter is approximately zero in the intermediate frequency band and is in a transmission state.

[0034] Figure 6 It is the S parameter of the multifunctional reconfigurable electromagnetic metasurface unit of the present invention when the PIN diode is in the ON state. It can be seen that the unit is in a total reflection state at this time.

[0035] Figure 7 The figure is a result diagram of the reflection Rxx and reflection Ryx of the multifunctional reconfigurable electromagnetic metasurface unit of the present invention under a single polarized incident wave. Ryx: reflection coefficient of the x-polarized incident wave converted into y-polarized wave; Rxx: reflection coefficient of the x-polarized wave.

[0036] Figure 8This is a diagram showing the actual phase value and difference between the "0" unit and the "1" unit of the multifunctional reconfigurable electromagnetic metasurface of the present invention. The "0" unit and the "1" unit are centrosymmetric structures, and the difference is that only the arrow direction of the polarization layer is distributed in a centrosymmetric position.

[0037] Fig. 9 It is a schematic diagram of a metasurface array in which the "0" unit and the "1" unit of the multifunctional reconfigurable electromagnetic metasurface of the present invention each form a 5×5 sub-array, and the sub-arrays form a checkerboard-arranged metasurface.

[0038] Fig.10 This is a comparison of the RCS of the multifunctional reconfigurable electromagnetic metasurface array of the present invention under TE / TM polarization and the metal floor of equal aperture. It can be seen that the RCS of the array structure is reduced compared with the metal floor under both polarization modes.

[0039] Fig.11 This is a bistatic RCS reduction curve at different incident angles when the multifunctional reconfigurable electromagnetic metasurface array of the present invention is in the ON state. It can be seen that the array RCS is reduced by more than 10dB within the working frequency band at different incident angles of 0°, 15°, and 30°.

[0040] Fig.12 This is a physical picture of the multifunctional reconfigurable electromagnetic metasurface array processing prototype of the present invention.

[0041] In summary, the present invention proposes an electromagnetic metasurface design that integrates multiple functions such as wave absorption, transmission, reflection, frequency selection, polarization twisting and diffuse scattering. In response to the requirements of the new generation of electromagnetic spectrum warfare systems for ultra-wideband, low profile, high efficiency, multi-function and high integration, the team designed a reconfigurable metasurface that takes into account the characteristics of bandwidth, function and frequency band continuity. At the same time, it solves the problem of using as few layers as possible to achieve high integration of metasurface multi-functions. It can also serve the ground combat vehicles, shipborne, and airborne ultra-wideband array radars in the new generation of electromagnetic spectrum warfare, and improve the wide-band and wide-spatial low-scattering stealth performance of the broadband tightly coupled array.

[0042] The above embodiments are merely illustrative of the principles and effects of the present invention, and are not intended to limit the present invention. Anyone familiar with the art may modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by a person of ordinary skill in the art without departing from the spirit and technical concept disclosed by the present invention shall still be covered by the claims of the present invention.

Claims

1. A broadband multifunctional reconfigurable electromagnetic metasurface, characterized in that: It includes an upper polarization twisting layer (1), a middle resistance loss layer (2), and a lower reconfigurable frequency selective surface layer (3); The polarization twisting layer (1) is loaded with centrally symmetrical arrow-shaped metal patches (4), which are centrally symmetrical and distributed at the diagonal edges of the surface layer; the front side of the resistance loss layer (2) is provided with eight package resistors (5) and square metal strips (6), the package resistors (5) are located at the edges of the front side of the resistance loss layer (2) and are connected via metal strips (6); the back side is provided with four spiral inductors (7), which are located at the center of each side of the resistance loss layer (2) and are connected via metal vias; the reconfigurable frequency selective surface layer (3) is divided into five layers from top to bottom, which are: a gradient trapezoidal metal patch (8) and a PIN diode (9), a dielectric substrate, a strip metal patch (10), a dielectric substrate, and a square metal patch (11), wherein the PIN diode (9) is located at the center of the reconfigurable frequency selective surface layer (3) and is connected to two gradient trapezoidal metal patches (8), which are welded via a PCB process, and the strip metal patch (10) and the square metal patch (11) are printed on the dielectric substrate, and the five-layer structure is formed by lamination via a PCB process.

2. The broadband multifunctional reconfigurable electromagnetic metasurface according to claim 1, characterized in that: The polarization twisted layer (1) is composed of a single layer of 0.127 mm thick Rogers RT / duroid 5880 microwave substrate with a dielectric constant of 2.2 and metal copper.

3. The broadband multifunctional reconfigurable electromagnetic metasurface according to claim 1, characterized in that: The resistance loss layer (2) is composed of a 0402 package resistor, a 1.57 mm thick Rogers RT / duroid 5880 microwave substrate with a dielectric constant of 2.2, and metal copper.

4. The broadband multifunctional reconfigurable electromagnetic metasurface according to claim 1, characterized in that: The reconfigurable frequency selective surface layer (3) is composed of a SMP1345-040LF model PIN diode, a FR-4_epoxy microwave substrate with a dielectric constant of 4.4, and metal copper.

5. The broadband multifunctional reconfigurable electromagnetic metasurface according to claim 1, characterized in that: The material of all metal patches is copper.

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