A multifunctional stealth metasurface with wave-absorbing tunable and wave-transmitting switchable functions

Abstract

The application discloses a multifunctional stealth metasurface with wave-absorbing adjustability and wave-transmitting switchability, and belongs to the technical field of electromagnetic functional materials. The multifunctional stealth metasurface 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, and the metasurface unit is arranged from top to bottom in sequence as a first resonance layer, a second resonance layer, the graphene capacitor layer, a third resonance layer and the frequency selective surface layer; gaps between the layers are 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; a PIN diode is integrated on the metal patch of the frequency selective surface layer; and the graphene capacitor layer is provided with a rectangular groove in the middle. The multifunctional stealth metasurface realizes tunable scattering characteristics and reconfigurable transmission characteristics of the metasurface, and has the advantages of wide scattering adjustment bandwidth, small transmission frequency band loss, low manufacturing cost, easy 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, communications, radar, and other fields. Metasurface technology has extremely high application value, and the design of radomes is one of them. Originally, radomes only had a protective function, with the main purpose of protecting the antenna from interference from the external environment that would affect its performance. With the development of metasurface technology, radomes have additional functions in addition to their protective functions, such as providing a switchable wave-transmitting window that can be opened when communication is required and closed when communication is not required. This allows the radome to protect the antenna while also improving its communication performance. 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 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 those with high reflectivity, the high absorption rate of the metasurface will reveal the location of the device. Therefore, there is an urgent need for a multifunctional stealth metasurface that has both scattering property adjustment and transmission property switching functions. It has a flexibly adjustable wave-transmitting window and can work in a variety of different environments to achieve stealth. 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 to solve the above problems.

[0005] To achieve the above-mentioned objectives, the present invention provides a multifunctional stealth metasurface with adjustable wave absorption and switchable wave transmission, which is composed of a periodically arranged number of metasurface units, wherein the metasurface unit includes a resonance layer, a graphene capacitor layer and a frequency selective surface layer, and 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 gaps between each layer are 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 both 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 both 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 employs the aforementioned structure to create a multifunctional stealth metasurface with both adjustable wave absorption and switchable wave transmission. This metasurface is composed of multiple metasurface units arranged in such a way that, when the PIN diode is off, it is equivalent to a series connection of a 30pH inductor and a 28fF capacitor; when the PIN diode is on, it is equivalent to a series connection of a 30pH inductor and a 7.8Ω resistor. By independently controlling the on-state voltages of the PIN diode and the graphene capacitor, the transmission and scattering properties can be independently adjusted. This not only enables tunable scattering and reconfigurable transmission properties, but also offers advantages such as a wide scattering adjustment bandwidth, minimal transmission band loss, low manufacturing cost, and ease of control. Due to these advantages, the proposed metasurface has potential applications in communications, military, and other fields.

[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 This 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 This is a schematic structural diagram of a metasurface unit resonant layer of an embodiment of a multifunctional stealth metasurface with both adjustable wave absorption and switchable wave transmission according to the present invention;

[0016] Figure 4 This is a schematic structural diagram of a graphene capacitor layer in a metasurface unit of an embodiment of a multifunctional stealth metasurface with adjustable wave absorption and switchable wave transmission according to the present invention;

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

[0018] Figure 6 This is 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 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 reflection coefficient curve of the metasurface unit when the square resistance of the graphene capacitor is 300Ω / m2 and the state of the PIN diode changes;

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

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

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

[0024] Description of the accompanying 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 embodiments described are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

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

[0027] It should also be noted that the terms "include," "comprises," or any other variations thereof are intended to encompass non-exclusive inclusion, such that a product or device comprising a series of elements includes not only those elements but also other elements not explicitly listed, or elements inherent to such product or device. In the absence of further limitations, an element defined by the phrase "comprises a..." does not exclude the presence of other identical elements in the product or device comprising the element.

[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 number of periodically arranged metasurface units, wherein the metasurface unit includes a resonance layer, a graphene capacitor layer and a frequency selective surface layer. 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. 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 frequency selective surface layer are composed of a dielectric substrate and a metal patch. The resonant layer dielectric substrate 1 and the frequency selective surface layer dielectric substrate 3 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 h1, the thickness of the dielectric substrate of the FSS layer is h2, and the material of the metal patch is copper, with a processing thickness set to 0.017mm.

[0030] The metal patches 1-1 of the first, second, and third resonant layers are identical in shape, forming a zigzag, square-shaped ring. The metal patch 3-1 of the frequency selective surface layer features a central cross structure, separated by a gap between the cross and the remaining metal patches. A PIN diode 4 (MA4AGP907) is integrated into the gap between the cross and the remaining metal patches. When the PIN diode is off, it acts like a 30pH inductor and a 28fF capacitor in series. When the PIN diode is on, it acts like a 30pH inductor and a 7.8Ω resistor in series.

[0031] The graphene capacitor layer 2 has a rectangular groove with a side length of w in the middle. The graphene capacitor consists 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-state voltage applied to its two ends. When the on-state voltage varies between -5V and 5V, the equivalent square resistance of the graphene capacitor is 200Ω / m 2 to 800Ω / m 2 Changes between.

[0032] The operating principle of the metasurface structured as described above, which achieves adjustable absorption and switchable transmission, is as follows: When the PIN diode is off, a low-loss conduction frequency appears at high frequencies. Changes in the sheet resistance of the graphene capacitor do not shift this conduction frequency; only its loss changes slightly, by less than 0.5 dB. When the PIN diode is on, the high-frequency conduction frequency disappears, and the transmission state changes to a reflection state. Transmission reconfiguration is achieved by changing the conduction state of the PIN diode and is virtually unaffected by changes in the sheet resistance of the graphene capacitor. When the sheet resistance of the graphene capacitor varies, its reflection coefficient can vary from -5 dB to -15 dB or -7 dB to -17 dB over a wide broadband range. Scattering tunability is achieved by varying the equivalent sheet resistance of the graphene capacitor and is largely unaffected by changes in the conduction state of the PIN diode. Independent control of the on-state voltages of the PIN diode and graphene capacitor allows for independent adjustment of the transmission and scattering properties.

[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 the 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 The reflection coefficient curve of the metasurface unit when the PIN diode is cut off is shown in the figure. In the 5.5-10.1 GHz frequency band, the reflection coefficient can be adjusted from -5dB to -15dB or -7dB to -17dB, with a tuning range of more than 10dB. Figure 7 The square resistance of the metasurface unit in the graphene capacitor is 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. The conduction frequency is 16.3GHz, and the transmission coefficient fluctuates between 0.7dB and 1.2dB, with a fluctuation range of less than 0.5dB. Figure 8 The square resistance of the metasurface unit in the graphene capacitor is 300Ω / m 2 ,The 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 significantly only at the transmission frequency point, while remaining basically unchanged in the absorption frequency band. Figure 9 The square resistance of the metasurface unit in the graphene capacitor is 300Ω / m 2Transmission 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 at the conduction frequency drops from -1dB to -15dB, and the transmission coefficient adjustment range exceeds 10dB. Figure 10 and Figure 11 The square resistance of the metasurface 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 initial design, CST Microwave Studio software was used for simulation analysis. After simulation optimization, various parameters and dimensions were obtained as 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 both adjustable absorption and switchable transmission exhibits broadband adjustable absorption and low insertion loss switchable transmission. Under bias voltage control, it can switch between different operating modes, achieving independent scattering tunability and reconfigurable transmission. Simulations demonstrate that the proposed metasurface unit exhibits excellent overall performance and has great potential for practical applications.

[0039] Therefore, the present invention employs the aforementioned structure to create a multifunctional stealth metasurface with both adjustable wave absorption and switchable wave transmission. This metasurface is composed of multiple metasurface units arranged in such a way that, when the PIN diode is off, it is equivalent to a series connection of a 30pH inductor and a 28fF capacitor; when the PIN diode is on, it is equivalent to a series connection of a 30pH inductor and a 7.8Ω resistor. By independently controlling the on-state voltages of the PIN diode and the graphene capacitor, the transmission and scattering properties can be independently adjusted. This not only enables tunable scattering and reconfigurable transmission properties, but also offers advantages such as a wide scattering adjustment bandwidth, minimal transmission band loss, low manufacturing cost, and ease of control. Due to these advantages, the proposed metasurface has potential applications in communications, military, and other fields.

[0040] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit the same. 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 solutions of the present invention with equivalents, and these modifications or equivalent replacements cannot cause the modified technical solutions to deviate from the spirit and scope of the technical solutions 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 includes a resonance layer, a graphene capacitor layer and a frequency selective surface layer. The resonance layer includes three layers, and the three resonance layers, graphene capacitor layers and frequency selective surface 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. The gaps between each layer are 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. 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 set 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 PMI foam has a dielectric constant of 1.08 and a tangent loss of 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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