Multifunctional stealth metasurface with adjustable wave absorption and switchable wave transmission

Abstract

The invention discloses a wave-absorbing and wave-transmitting switchable multifunctional stealth metasurface, and belongs to the technical field of electromagnetic functional materials, the metasurface is formed by periodically arranging a plurality of metasurface units, each metasurface unit comprises a resonance layer, a graphene capacitor layer and a frequency selection surface layer, a first resonance layer, a second resonance layer, a graphene capacitor layer, a third resonance layer and a frequency selective surface layer are sequentially arranged from top to bottom, and gaps between the layers are filled with PMI foam to serve as supports. The resonance layer and the frequency selection surface layer are formed by a dielectric substrate and a metal patch; a PIN diode is integrated on the metal patch of the frequency selection surface layer; and a rectangular groove is formed in the middle of the graphene capacitor layer. According to the multifunctional stealth metasurface, the scattering characteristic of the metasurface is tunable, the transmission characteristic of the metasurface is reconfigurable, and the multifunctional stealth metasurface has the advantages of being wide in scattering adjustment bandwidth, small in transmission frequency band loss, low in manufacturing cost, easy to adjust and control and the like.

Description

Technical Field

[0001] The present invention relates to the technical field of electromagnetic functional materials, and in particular to a multifunctional stealth metasurface with adjustable wave absorption and switchable wave transmission. Background Art

[0002] Metasurfaces play an important role in imaging, sensing, communication, radar and other fields. Metasurface technology has extremely high application value, and the design of radome is one of them. The original radome only had a protective function, and its main purpose was to protect the antenna from being disturbed by the external environment and affecting its performance. With the development of metasurface technology, the radome has additional functions in addition to the protective function, such as providing a switchable wave-transmitting window, which is opened when communication is required and closed when communication is not required. This allows the radome to protect the antenna while improving the communication performance of the antenna. However, with the development of radar detection technology, the stealth performance of communication equipment and military equipment has become increasingly important.

[0003] The indicator for measuring electromagnetic stealth performance is the radar cross-section (RCS). The smaller the RCS, the better the stealth performance. However, most of the current metasurfaces absorb electromagnetic waves by adding absorbing materials to reduce the RCS of the device, and do not have flexible and adjustable absorption functions. Although this method can reduce the RCS of the device in most environments, in certain specific environments, such as in certain environments with high reflectivity, the high absorption rate of the metasurface will expose the location of the device. Therefore, there is an urgent need for a multifunctional stealth metasurface that has both scattering characteristic adjustment function and transmission characteristic switching function. It has a flexibly adjustable wave-transmitting window and can work in a variety of different environments to achieve stealth function. Summary of the invention

[0004] The purpose of the present invention is to provide a multifunctional stealth metasurface with adjustable wave absorption and switchable wave transmission, so as to solve the above problems.

[0005] To achieve the above-mentioned purpose, the present invention provides a multifunctional stealth metasurface with adjustable wave absorption and switchable wave transmission, which is composed of a number of metasurface units arranged periodically, wherein the metasurface unit includes a resonance layer, a graphene capacitor layer and a frequency selective surface layer, wherein the resonance layer includes three layers, and the three layers of the resonance layer, the graphene capacitor layer and the frequency selective surface layer are arranged from top to bottom as a first resonance layer, a second resonance layer, a graphene capacitor layer, a third resonance layer and a frequency selective surface layer, and the gap between each layer is filled with PMI foam as support; the resonance layer and the frequency selective surface layer are composed of a dielectric substrate and a metal patch, and the metal patches of the first resonance layer, the second resonance layer and the third resonance layer have the same shape, which is a square ring with a bending structure; the metal patch structure of the frequency selective surface layer has a cross structure in the middle, and a gap is provided between the cross structure and other parts of the metal patch structure, and a PIN diode is integrated in the gap between the cross structure and other parts of the metal patch structure; the graphene capacitor layer has a rectangular groove in the middle.

[0006] Preferably, in the above-mentioned multifunctional stealth metasurface with adjustable wave absorption and switchable wave transmission, the dielectric substrate is a CFS300 substrate with a dielectric constant of 3 and a tangent loss of 0.001.

[0007] Preferably, in the above-mentioned multifunctional stealth metasurface with adjustable wave absorption and switchable wave transmission, the dielectric constant of the PMI foam is 1.08 and the tangent loss is 0.003.

[0008] Preferably, in the above-mentioned multifunctional stealth metasurface with adjustable wave absorption and switchable wave transmission, the material of the metal patch is copper, and the processing thickness is set to 0.017 mm.

[0009] Preferably, in the above-mentioned multifunctional stealth metasurface with adjustable wave absorption and switchable wave transmission, the PIN diode model is MA4AGP907.

[0010] Preferably, in the above-mentioned multifunctional stealth metasurface with adjustable wave absorption and switchable wave transmission, the graphene capacitor is composed of a graphene film and a high-impedance sheet separated by an electrolyte layer.

[0011] Therefore, the present invention adopts a multifunctional stealth metasurface with adjustable wave absorption and switchable wave transmission using the above structure, which is composed of multiple metasurface units. When the PIN diode is cut off, it is equivalent to an inductor of 30pH and a capacitor of 28fF in series; when the PIN diode is turned on, it is equivalent to an inductor of 30pH and a resistor of 7.8Ω in series. By independently controlling the on-voltage of the PIN diode and the graphene capacitor, the transmission characteristics and the scattering characteristics are independently adjusted, which not only realizes the tunable scattering characteristics and reconfigurable transmission characteristics of the metasurface, but also has the advantages of wide scattering adjustment bandwidth, small transmission frequency band loss, low manufacturing cost, and easy regulation. Due to the above advantages, the proposed metasurface has potential application value in the fields of communication and military.

[0012] The technical solution of the present invention is further described in detail below through the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 It is a schematic diagram of the overall structure of a metasurface unit of an embodiment of a multifunctional stealth metasurface with adjustable wave absorption and switchable wave transmission according to the present invention;

[0014] Figure 2 A side view of a metasurface unit of an embodiment of a multifunctional stealth metasurface with adjustable wave absorption and switchable wave transmission according to the present invention;

[0015] Figure 3 A schematic diagram of the structure of a supersurface unit resonance layer of an embodiment of a multifunctional stealth supersurface with adjustable wave absorption and switchable wave transmission according to the present invention;

[0016] Figure 4 A schematic diagram of the structure of a graphene capacitor layer of a supersurface unit of an embodiment of a multifunctional stealth supersurface with adjustable wave absorption and switchable wave transmission according to the present invention;

[0017] Figure 5 A schematic diagram of the structure of a frequency selective surface layer of a metasurface unit of an embodiment of a multifunctional stealth metasurface with adjustable wave absorption and switchable wave transmission according to the present invention;

[0018] Figure 6 The reflection coefficient curve of the metasurface unit when the square resistance of the graphene capacitor changes between 200Ω / m2 and 800Ω / m2 and the PIN diode is cut off;

[0019] Figure 7 It is the transmission coefficient curve of the metasurface unit when the square resistance of the graphene capacitor changes between 200Ω / m2 and 800Ω / m2 and the PIN diode is cut off;

[0020] Figure 8The square resistance of the graphene capacitor is 300Ω / m2, and the reflection coefficient curve of the metasurface unit when the state of the PIN diode changes;

[0021] Fig. 9 The graphene capacitor has a square resistance of 300Ω / m2 and the transmission coefficient curve of the metasurface unit when the PIN diode state changes;

[0022] Fig.10 The square resistance of the graphene capacitor is 300Ω / m2, and the reflection coefficient curve of the metasurface unit at different incident angles when the PIN diode is cut off;

[0023] Fig.11 The square resistance of the graphene capacitor is 300Ω / m2. When the PIN diode is cut off, the transmission coefficient curve of the metasurface unit at different incident angles.

[0024] Description of the drawings: 1. Resonance layer dielectric substrate; 1-1. Metal patch of the resonance layer; 2. Graphene capacitor layer; 3. Dielectric substrate of the frequency selective surface layer; 3-1. Metal patch of the frequency selective surface layer; 4. PIN diode; 5-PMI foam. DETAILED DESCRIPTION

[0025] In order to better understand the above technical solution, the above technical solution will be described in detail below in conjunction with the accompanying drawings and specific implementation methods. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0026] The terms used in the embodiments of the present invention are only for the purpose of describing specific embodiments, and are not intended to limit the present invention. The singular forms "a", "said" and "the" used in the embodiments of the present invention and the appended claims are also intended to include plural forms, unless the context clearly indicates other meanings, and "multiple" generally includes at least two.

[0027] It should also be noted that the term "includes", "comprising" or any other variation thereof is intended to cover non-exclusive inclusion, so that a commodity or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such commodity or device. In the absence of more restrictions, the elements defined by the sentence "comprising a ..." do not exclude the existence of other identical elements in the commodity or device including the elements.

[0028] See attached Figure 1-5As shown, the present invention provides a multifunctional stealth metasurface with adjustable wave absorption and switchable wave transmission, which is composed of a plurality of metasurface units arranged periodically, wherein the metasurface unit includes a resonance layer, a graphene capacitor layer and a frequency selective surface layer, wherein the resonance layer includes three layers, and the three resonance layers, graphene capacitor layers and frequency selective surface (FSS) layers are arranged from top to bottom as a first resonance layer, a second resonance layer, a graphene capacitor layer, a third resonance layer and a frequency selective surface layer, and the gap between each layer is filled with PMI foam 5 as support, and the dielectric constant of the PMI foam is 1.08 and the tangent loss is 0.003.

[0029] The resonant layer and the frequency selective surface layer are composed of a dielectric substrate and a metal patch. The dielectric substrate 1 of the resonant layer and the dielectric substrate 3 of the frequency selective surface layer are CFS300 substrates, with a dielectric constant of 3 and a tangent loss of 0.001. The thickness of the dielectric substrates of the three resonant layers is h 1 , the thickness of the dielectric substrate of the FSS layer is h 2 ,The material of the metal patch is copper, and the processing thickness is set to 0.017mm.

[0030] The metal patches 1-1 of the first resonant layer, the second resonant layer and the third resonant layer have the same shape, which is a quasi-square ring with a bent structure; the metal patch 3-1 structure of the frequency selective surface layer has a cross structure in the middle, and a gap is set between the cross structure and other metal patch structures, and a PIN diode 4 is integrated on the gap between the cross structure and other metal patch structures. The PIN diode model is MA4AGP907. When the PIN diode is cut off, it is equivalent to a 30pH inductor and a 28fF capacitor connected in series; when the PIN diode is turned on, it is equivalent to a 30pH inductor and a 7.8Ω resistor connected in series.

[0031] The graphene capacitor layer 2 has a rectangular groove with a side length of w in the middle. The graphene capacitor is composed of a graphene film and a high impedance sheet separated by an electrolyte layer. The equivalent square resistance of the graphene capacitor is adjusted by changing the on-voltage loaded at both ends. When the on-voltage changes between -5V and 5V, the equivalent square resistance of the graphene capacitor is 200Ω / m 2 Up to 800Ω / m 2 Changes between.

[0032] The working principle of realizing the adjustable wave absorption and switchable wave transmission of the metasurface composed of the above structure is as follows: when the PIN diode is cut off, a low-loss conduction frequency point appears at high frequency, and the change of the square resistance of the graphene capacitor will not cause the conduction frequency point to shift, only its loss will change slightly, and the change range is less than 0.5dB. When the PIN diode is turned on, the conduction frequency point appearing at high frequency disappears, and the transmission state changes to the reflection state. That is, the transmission reconfiguration is achieved by changing the conduction state of the PIN diode and is hardly affected by the change of the square resistance of the graphene capacitor. When the square resistance value of the graphene capacitor changes, its reflection coefficient can change from -5dB to -15dB or -7dB to -17dB in a wide broadband range. That is, the tunable scattering is achieved by changing the equivalent square resistance value of the graphene capacitor and is basically not affected by the change of the conduction state of the PIN diode. By independently controlling the conduction voltage of the PIN diode and the graphene capacitor, the independent adjustment of the transmission characteristics and the scattering characteristics is achieved.

[0033] The influence of the change of the square resistance of graphene capacitor and the change of the state of PIN diode on the reflection and transmission coefficient of metasurface unit is studied. The specific research content includes the following: 2 ~800Ω / m 2 ) and reflection and transmission characteristics of the metasurface unit under different PIN diode states and different incident angles; Figure 6 The proposed metasurface unit is given in the graphene capacitor with a square resistance of 200Ω / m 2 ~800Ω / m 2 When the PIN diode is cut off, the reflection coefficient curve of the metasurface unit changes between -5dB and -15dB or -7dB and -17dB in the 5.5-10.1GHz band, and the reflection coefficient tuning range exceeds 10dB. Figure 7 The metasurface unit in the graphene capacitor has a square resistance of 200Ω / m. 2 ~800Ω / m 2 When the PIN diode is turned off, the transmission coefficient curve of the metasurface unit changes between 0.7dB and 1.2dB, and the fluctuation range is less than 0.5dB. Figure 8 The square resistance of the super surface unit in the graphene capacitor is 300Ω / m. 2 , Reflection coefficient curve of the metasurface unit when the PIN diode state changes. It can be seen that when the PIN diode conduction state changes, its reflection coefficient changes greatly only at the wave transmission frequency point, while it remains basically unchanged in the wave absorption frequency band. Fig. 9 The square resistance of the super surface unit in the graphene capacitor is 300Ω / m. 2, Transmission coefficient curve of the metasurface unit when the PIN diode state changes. The conduction frequency is 16.3GHz. When the PIN diode conduction state changes, the transmission coefficient of the conduction frequency drops from -1dB to -15dB, and the transmission coefficient adjustment range exceeds 10dB. Fig.10 and Fig.11 The square resistance of the super surface unit in the graphene capacitor is 300Ω / m. 2 ,When the PIN diode is cut off, the S parameter curves at different incident angles,when the incident angle is lower than 40°, the performance of the metasurface unit remains basically unchanged,and when the incident angle exceeds 40°, the performance of the metasurface unit will gradually decrease.

[0034] After completing the above initial design, CST Microwave Studio software was used for simulation analysis. After simulation optimization, various parameters were obtained and the dimensions are shown in Table 1:

[0035] Table 1 Optimal size table of various parameters of the present invention

[0036]

[0037]

[0038] In summary, the proposed multifunctional stealth metasurface with adjustable wave absorption and switchable wave transmission has the characteristics of broadband adjustable wave absorption and low insertion loss switchable wave transmission. Under the control of bias voltage, different working modes can be switched, and independent scattering tunability and transmission reconfiguration are achieved. After simulation, the proposed metasurface unit has good overall performance and has extremely high practical application potential.

[0039] Therefore, the present invention adopts a multifunctional stealth metasurface with the above structure that has both adjustable wave absorption and switchable wave transmission. It is composed of multiple metasurface units. When the PIN diode is cut off, it is equivalent to an inductor of 30pH and a capacitor of 28fF in series; when the PIN diode is turned on, it is equivalent to an inductor of 30pH and a resistor of 7.8Ω in series. By independently controlling the on-voltage of the PIN diode and the graphene capacitor, the transmission characteristics and the scattering characteristics are independently adjusted, which not only realizes the tunable scattering characteristics and reconfigurable transmission characteristics of the metasurface, but also has the advantages of wide scattering adjustment bandwidth, small transmission frequency band loss, low manufacturing cost, and easy regulation. Due to the above advantages, the proposed metasurface has potential application value in the fields of communication and military.

[0040] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that they can still modify or replace the technical solution of the present invention with equivalents, and these modifications or equivalent replacements cannot cause the modified technical solution to deviate from the spirit and scope of the technical solution of the present invention.

Claims

1. A multifunctional stealth metasurface with adjustable wave absorption and switchable wave transmission, characterized in that: The invention is composed of a plurality of metasurface units arranged periodically, wherein the metasurface unit comprises a resonance layer, a graphene capacitor layer and a frequency selective surface layer, wherein the resonance layer comprises three layers, wherein the three resonance layers, the graphene capacitor layer and the frequency selective surface layer are arranged from top to bottom in the order of a first resonance layer, a second resonance layer, a graphene capacitor layer, a third resonance layer and a frequency selective surface layer, and the gaps between each layer are filled with PMI foam as support; the resonance layer and the frequency selective surface layer are formed by a dielectric substrate and a metal patch, wherein the metal patches of the first resonance layer, the second resonance layer and the third resonance layer have the same shape, and are quasi-square rings with a bending structure; the metal patch structure of the frequency selective surface layer has a cross structure in the middle, and a gap is provided between the cross structure and other parts of the metal patch structure, and a PIN diode is integrated in the gap between the cross structure and other parts of the metal patch structure; the graphene capacitor layer has a rectangular groove in the middle.

2. The multifunctional stealth metasurface with adjustable wave absorption and switchable wave transmission according to claim 1, characterized in that: The dielectric substrate is a CFS300 substrate with a dielectric constant of 3 and a tangent loss of 0.

001.

3. The multifunctional stealth metasurface with adjustable wave absorption and switchable wave transmission according to claim 2, characterized in that: The dielectric constant of the PMI foam is 1.08 and the tangent loss is 0.

003.

4. The multifunctional stealth metasurface with adjustable wave absorption and switchable wave transmission according to claim 3, characterized in that: The material of the metal patch is copper, and the processing thickness is set to 0.017mm.

5. The multifunctional stealth metasurface with adjustable wave absorption and switchable wave transmission according to claim 4, characterized in that: The PIN diode model is MA4AGP907.

6. The multifunctional stealth metasurface with adjustable wave absorption and switchable wave transmission according to claim 5, characterized in that: The graphene capacitor consists of a graphene film and a high-impedance sheet separated by an electrolyte layer.

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