CN110783714A - Graphene-based transmission dynamic adjustable flexible frequency selective wave absorber - Google Patents
Graphene-based transmission dynamic adjustable flexible frequency selective wave absorber Download PDFInfo
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- CN110783714A CN110783714A CN201910886991.0A CN201910886991A CN110783714A CN 110783714 A CN110783714 A CN 110783714A CN 201910886991 A CN201910886991 A CN 201910886991A CN 110783714 A CN110783714 A CN 110783714A
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01Q—ANTENNAS, i.e. RADIO AERIALS
- H01Q17/00—Devices for absorbing waves radiated from an antenna; Combinations of such devices with active antenna elements or systems
- H01Q17/007—Devices for absorbing waves radiated from an antenna; Combinations of such devices with active antenna elements or systems with means for controlling the absorption
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01Q—ANTENNAS, i.e. RADIO AERIALS
- H01Q1/00—Details of, or arrangements associated with, antennas
- H01Q1/42—Housings not intimately mechanically associated with radiating elements, e.g. radome
- H01Q1/422—Housings not intimately mechanically associated with radiating elements, e.g. radome comprising two or more layers of dielectric material
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Abstract
The invention discloses a graphene-based transmission dynamic adjustable flexible frequency selective wave absorber, which belongs to the technical field of microwave devices and comprises a graphene metal mixed layer, a first dielectric layer, a graphene-electrolyte-graphene sandwich layer, a second dielectric layer and a metal frequency selective surface layer which are stacked from top to bottom. The graphene is used for realizing a passband with small insertion loss, and two absorption bands with high wave-absorbing rate are arranged on the left and right of the passband. The present invention can be applied to a wide wavelength region ranging from microwave to terahertz because of no lumped element. In addition, the adjustable transmission on the pass band is realized through the graphene sandwich structure, so that the frequency selective wave absorber has the function of continuous spatial energy manipulation, and the antenna housing has a great application prospect in the aspects of electromagnetic stealth, compatibility and protection.
Description
Technical Field
The invention belongs to the technical field of microwave devices, and particularly relates to a graphene-based transmission dynamic adjustable flexible frequency selective wave absorber.
Background
The radome is a cover placed on the antenna for protecting the radiating elements from the external environment, such as wind, rain, ice and sand. In addition to physical protection, from an electromagnetic point of view, the radome should be transparent to radio frequencies so that it does not degrade the electrical performance of the enclosed antenna. Conventional radomes are usually composed of frequency selective surfaces because they have attractive frequency filtering characteristics. In most cases, bandpass FSS is used to allow waves to pass without too much passband loss, but there is a strong reflection passband, greatly increasing the radar cross section. The ideal way to reduce the out-of-band bistatic radar cross section is to use lossy materials in the design and manufacture of radomes to absorb the incident waves, thus proposing a structure called frequency selective absorber (FSR).
In general, existing FSRs can be divided into two categories: two-dimensional FSRs and three-dimensional FSRs. While three-dimensional FSRs show the advantages of smaller cell size and stable oblique incidence performance, the thickness is greatly increased, thus limiting its practical application, and thus only two-dimensional FSRs are discussed and studied in our work. In the past, two-dimensional FSRs were typically implemented by placing a lossy layer over the lossless bandpass FSS, with the absorptive function being provided by the lossy layer, such as resistive square rings, resistive patches, and resistive rings. These structures have the weakness of relatively low transmission in the transmission band, which results in inevitable insertion losses of purely resistive lossy layers. Later, attempts were made to improve the transmission performance of FSRs by loading lumped resistors in the metal elements. The added metal components provide strong LC resonances in the transmission window, resulting in high impedance on the lossy layer, and hence can improve the transmittance. However, too many lumped elements are used, which may lead to rather complex design and manufacturing, and PCB board based manufacturing techniques limit their application in flexible or conformal cases. Furthermore, these designs fail at high frequencies (e.g., terahertz bands) because it is difficult to use lumped elements at such high frequencies.
For the above mentioned absorbers, the operating band is transparent to in-band signals, so High Intensity Radiation Fields (HIRF) and electromagnetic pulses (EMP) can enter the system and cause irreparable damage to the electronics. To address this problem, we have investigated FSRs with switchable passbands, an existing switchable property being the change in state of the diode driven by the biasing gate. These PIN diode based structures also suffer from complex manufacturing processes and limited applicable frequency ranges. More importantly, only binary functions of the transmission properties, i.e. "on" and "off" states, can be implemented. The value of the threshold field strength is limited primarily by the inherent characteristics of the PIN diode. In this case, continuously adjusting the incident wave power remains a challenge to be solved.
Disclosure of Invention
The purpose of the invention is as follows: in order to solve the problems in the prior art, the invention provides a graphene-based transmission dynamic adjustable flexible frequency selective wave absorber, which realizes that an adjustable pass band is arranged between two adjacent absorption bands, and the two adjacent absorption bands have band-pass characteristics of high permeability and high absorptivity, and can realize continuously adjustable transmissivity on a transmission window through active dynamic regulation, so that the frequency selective wave absorber has the functions of energy manipulation and arbitrary controllability.
The technical scheme is as follows: in order to achieve the purpose, the invention adopts the following technical scheme:
the graphene-based transmission dynamic adjustable flexible frequency selective wave absorber comprises a graphene metal mixing layer, a first dielectric layer, a graphene-electrolyte-graphene sandwich structure, a second dielectric layer and a metal frequency selective surface layer which are arranged in an overlapped mode; the graphene metal mixed layer comprises a plurality of graphene layers and metal arms, the graphene layers are of annular structures, and the four metal arms are arranged on the periphery of the graphene layers at equal intervals; the metal arms are respectively communicated with the interiors of the multilayer graphene layers.
Further, the graphene metal mixed layer and the metal frequency selective surface layer are each formed by laminating PVC on a copper foil, then printing a pattern on the laminated copper foil using a laser printer, etching the printed laminated copper foil in an aqueous nitric acid solution and using the printed toner as an etching mask, and the laminated copper under the toner is not etched to produce a pattern made of the laminated copper foil.
Furthermore, the metal frequency selective surface layer is a complementary circular ring type periodic structure formed by etching a copper sheet.
Further, the multilayer graphene layer is grown on a pre-patterned nickel foil, and the square resistance of the obtained fan-shaped structure is 70 ohm/sq by controlling the growth temperature to 903 ℃.
Further, the graphene sandwich structure comprises two single-layer graphene and diaphragm paper arranged between the two single-layer graphene; the diaphragm paper is soaked in electrolyte, and each single-layer graphene is respectively connected with a bias voltage.
Further, the electrolyte layer is formed by mixing diethyl methyl phthalate, trifluoromethanesulfonimide and Tf2N ionic liquid.
Further, the outer diameter r of the multilayer graphene layer
13 mm, inner diameter r
22 mm, the length l of each metal arm is 4.97mm, and the gap width w
10.5mm, and an arm length width excluding a slit width is w
21 mm; the metal frequency selective surface layer is a complementary annular periodic structure etched by a copper sheet with the thickness of 10 microns, and the inner diameter r
35.14mm, outer diameter r
44.14 mm; the first medium layer and the second medium layer are both foam boards, the foam board material is polyethylene terephthalate, and the thicknesses of the foam boards are respectively 3 mm; the thickness of the graphene-electrolyte-graphene sandwich structure is 190 micrometers; the graphene-electrolyte-graphene sandwich structure is formed by processing a single-layer graphene spread on a PVC film substrate, and the thickness of the PVC film substrate is 60 micrometers.
Further, the thickness of the wave absorber is 6 mm, the size of the wave absorber is 27cm multiplied by 27cm, and the wave absorber comprises 18 multiplied by 18 square ring units; wherein the size of each square ring unit is 15mm multiplied by 15 mm.
The invention principle is as follows: the graphene-based transmission dynamically adjustable flexible frequency selective wave absorber comprises a graphene metal mixed layer, a first dielectric layer, a graphene-electrolyte-graphene sandwich structure, a second dielectric layer and a metal frequency selective surface layer. When an electromagnetic wave is incident to the device, the fan-shaped multi-layer graphene in the graphene metal mixed layer and the metal frequency selective surface of the bottom layer form two absorption peaks, and surface current can flow through the fan-shaped patch at f1 and f3, so that the multi-layer graphene absorbs the electromagnetic wave of two adjacent absorption bands due to ohmic loss. In contrast, resonances occur at the four metal arms at f2 and the metal frequency selective surface, which prevent surface currents from flowing along the lossy patch, so a transmission window with low losses can be achieved, allowing electromagnetic waves to pass through. Through the graphene electrolyte interlayer in the middle, the conductivity of the graphene electrolyte interlayer can be dynamically adjusted by external voltage, the surface impedance of the graphene sandwich layer is influenced, and therefore the transmissivity of a pass band is influenced.
The present invention designs and manufactures two-dimensional FSRs in which the lossy layers are based on multi-layer graphene (MLG) integrated with metal arms. The composite structure has high permeability and absorption band-pass characteristics between two adjacent absorption bands, and has the advantages of easy fibrosis and wide frequency applicability. To overcome the inflexibility of conventional FSRs, ultra-thin polyvinyl chloride (PVC) was chosen as the substrate for the lossy and lossless layers, and prototypes were made with good flexibility and low weight. It is worth noting that continuously adjustable transmittance on the transmission window is realized by using Graphene-enabled electrically switchable Graphene-absorbing surfaces (GSS), so that our frequency selective wave absorber has functions of energy manipulation and arbitrary controllability.
Has the advantages that: compared with the prior art, the graphene-based transmission dynamic adjustable flexible frequency selective wave absorber disclosed by the invention has the advantages that the voltage dynamic adjustment graphene technology and the frequency selective surface are combined together to form the electromagnetic wave absorbing surface, the pass band with small insertion loss is realized by using the graphene, the composite structure has the band-pass characteristics of high permeability and absorptivity between two adjacent absorption bands, and meanwhile, the structure has the advantages of easiness in fibrosis and wide frequency applicability. The inflexibility of the traditional FSR is overcome, ultrathin polyvinyl chloride (PVC) is selected as a substrate of a destructive layer and a nondestructive layer, and the manufactured prototype has good flexibility and low weight. The Graphene Sandwich Structure (GSS) is used for realizing continuously adjustable transmittance on the transmission window, so that the frequency-selective wave absorber has the functions of energy manipulation and arbitrary controllability, and the antenna housing has a great application prospect in the aspects of electromagnetic stealth, compatibility and protection.
Drawings
Fig. 1 is a side view of a transmission tunable flexible frequency selective absorber based on electrolyte tuning graphene;
FIG. 2 is a schematic diagram of a graphene metal mixed layer pattern structure;
FIG. 3 is a schematic view of a metal pattern structure of a metal frequency selective surface layer;
FIG. 4 is an equivalent circuit schematic diagram of a wave absorbing principle of the designed electromagnetic wave absorbing surface;
FIG. 5 is a histogram of dynamically modulated transmittance;
FIG. 6 is a frequency distribution graph of a dynamically modulated absorption rate;
FIG. 7 is a histogram of dynamically modulated reflectivity;
reference numerals: the structure comprises a 1-graphene metal mixed layer, a 2-first dielectric layer, a 3-graphene-electrolyte-graphene sandwich structure, a 4-second dielectric layer, a 5-metal frequency selective surface layer, 11-multilayer graphene layers and 12-metal arms.
Detailed Description
The invention is further described with reference to the following figures and specific examples. It is to be understood that these examples are for illustrative purposes only and are not intended to limit the scope of the present invention, which is to be given the full breadth of the appended claims and any and all equivalent modifications thereof which may occur to those skilled in the art upon reading the present specification.
As shown in fig. 1, the transmission adjustable flexible frequency selective wave absorber based on electrolyte controlled graphene comprises five layers of structures stacked from bottom to top: the device comprises a graphene metal mixed layer 1, a first dielectric layer 2, a graphene-electrolyte-graphene sandwich structure 3, a second dielectric layer 4 and a metal frequency selection surface layer 5; the method comprises the steps of arranging a second dielectric layer 4 on a metal selective frequency surface layer 5, arranging a graphene-electrolyte-graphene sandwich structure 3 on the second dielectric layer 4, arranging a first dielectric layer 2 on the graphene-electrolyte-graphene sandwich structure 3, and arranging a graphene metal mixed layer 1 on the first dielectric layer 2. Wherein, in the graphene-electrolyte-graphene sandwich structure 3, two graphene layers are both formed by laying single-layer graphene on a PVC substrate.
The patterns of the graphene metal hybrid layer 1 and the metal frequency selective surface layer 5 were each obtained by laminating PVC on a 10 μm copper foil and then printing the patterns on the laminated copper foil using a laser printer. The printed laminated copper foil is then etched in an aqueous nitric acid solution and the printed toner is used as an etch mask, and the laminated copper foil under the toner is not etched to produce a pattern made of the laminated copper foil.
As shown in fig. 2, the graphene metal mixed layer 1 includes a plurality of graphene layers 11 and metal arms 12, the graphene layers 11 are ring-shaped structures, the metal arms 12 are four and equally spaced, and are respectively communicated with the inside of the graphene layers 11 at the periphery of the graphene layers 11, and the specific parameters are: outer diameter r
13 mm, inner diameter r
22 mm, the length l of each metal arm is 4.97mm, and the gap width w
10.5mm, and an arm length width excluding a slit width is w
21 mm. The multilayer graphene is a fan-shaped structure which is grown on a pre-patterned nickel foil and has a square resistance of 70 ohm/sq by controlling the growth temperature to 903 ℃. Each cell size is 15mm by 15 mm.
As shown in FIG. 3, the metal frequency selective surface layer 5 is a copper foil 10 μm thick etched to a complementary circular periodic structure with an inner diameter r
35.14mm, outer diameter r
44.14 mm. The overall wave absorber has the structural size of 27cm multiplied by 27cm and comprises 18 multiplied by 18 square ring units; wherein the size of each square ring unit is 15mm multiplied by 15 mm.
The first dielectric layer 2 and the second dielectric layer 4 are both polyethylene terephthalate foam boards, the thicknesses of the first dielectric layer 2 and the second dielectric layer 4 are 3 millimeters respectively, the first dielectric layer and the second dielectric layer are mainly used for separating the graphene metal mixed layer 1, the graphene-electrolyte-graphene sandwich structure 3 and the metal frequency selective surface layer 5 so as to prevent voltage from leaking to the metal surface, and the first dielectric layer 2 and the second dielectric layer 4 both have the characteristics of light weight, thin thickness and good isolation.
The graphene-electrolyte-graphene sandwich structure 3 is formed by laying single-layer graphene on a PVC substrate and processing, and the thickness of the graphene-electrolyte-graphene sandwich structure 3 is 190 micrometers. The thickness of the PVC film substrate was 60 μm. The electrolyte layer is formed by mixing diethyl methyl benzenedioate, trifluoromethanesulfonimide and Tf2N (1-ethyl-3-methylimidazolium bistrifluoromethylsulfimide salt) ionic liquid. In fig. 6-7, V refers to the voltage applied to the electrodes on the two layers of graphene, ranging from 0 volts to +4 volts. The electrolyte layer 12 is 1-butyl-3-methylimidazolium hexafluorophosphate belonging to scientific research brands; CAS: 174501-64-5; more than or equal to 99 percent; [ BMIM ] PF 6.
Fig. 4 is an equivalent circuit schematic diagram of the principle of a graphene-based transmission tunable flexible frequency selective wave absorber. The specific principle is as follows: the frequency selective surface layer is equivalent to an inductance L in this design
2And a capacitor C
2And in the parallel circuit, the graphene metal mixed layer is equivalent to an RLC circuit. In an operating frequency band, the fan-shaped multilayer graphene in the graphene metal mixed layer and the metal frequency selective surface of the bottom layer form two absorption peaks, and surface current can flow through the fan-shaped patch at f1 and f3, so that the multilayer graphene absorbs electromagnetic waves of two adjacent absorption bands due to ohmic loss. In contrast, resonances occur at the four metal arms at f2 and the metal frequency selective surface, which prevent surface currents from flowing along the lossy patch, so a transmission window with low losses can be achieved, allowing electromagnetic waves to pass through.
As shown in FIGS. 5-7, no matter how the voltage changes, the transmissivity, the wave-absorbing rate and the reflectivity at the positions of f1:4GHz-10GHz and f3:14GHz-20GHz have no obvious change, the wave-absorbing rate is stabilized at more than 80%, the wave-absorbing function is realized in the frequency bands of f1 and f3, and the frequency bands of f2:10-14GHz can cause the obvious change of the transmissivity due to the change of the applied voltage. When the applied voltage is changed from 0V to 4V, the surface impedance of the graphene is adjusted to change at 1250-280 omega, the transmissivity of the frequency selective wave absorber at the central frequency band of f2 is changed from 0.67 to 0.35, and when the graphene is not added, the transmissivity is more than 80% at the central frequency band, so that most wave can transmit through. While the reflectivity is small and does not change significantly in all three frequency bands. Therefore, the invention realizes a frequency selective wave absorber with dynamically adjustable transmission, realizes high wave absorption rate at frequency bands of f1 and f3, and can dynamically adjust the transmission rate at a frequency band of f2 through a graphene sandwich structure.
Claims (8)
1. The utility model provides a flexible frequency selection wave absorber that transmission developments are adjustable based on graphite alkene which characterized in that: the graphene-electrolyte-graphene sandwich structure comprises a graphene metal mixed layer (1), a first dielectric layer (2), a graphene-electrolyte-graphene sandwich structure (3), a second dielectric layer (4) and a metal frequency selection surface layer (5) which are arranged in an overlapped mode; the graphene metal mixed layer (1) comprises a plurality of graphene layers (11) and metal arms (12), wherein the graphene layers (11) are of an annular structure, and the four metal arms (12) are arranged on the periphery of the graphene layers (11) at equal intervals; the metal arms (12) are respectively communicated with the interiors of the multilayer graphene layers (11).
2. The graphene-based transmissive dynamically tunable flexible frequency selective wave absorber of claim 1, wherein: the graphene metal mixed layer (1) and the metal frequency selective surface layer (5) are both formed by laminating PVC on a copper foil, then printing a pattern on the laminated copper foil by using a laser printer, etching the printed laminated copper foil in a nitric acid aqueous solution, using the printed toner as an etching mask, and generating a pattern made of the laminated copper foil without etching the laminated copper under the toner.
3. The graphene-based transmissive dynamically tunable flexible frequency selective wave absorber of claim 1, wherein: the metal frequency selective surface layer (5) is a complementary circular ring type periodic structure formed by etching a copper sheet.
4. The graphene-based transmissive dynamically tunable flexible frequency selective wave absorber of claim 1, wherein: the multilayer graphene layer (11) is grown on a pre-patterned nickel foil, and the square resistance of the obtained fan-shaped structure is 70 ohm/sq by controlling the growth temperature to 903 ℃.
5. The graphene-based transmissive dynamically tunable flexible frequency selective wave absorber of claim 1, wherein: the graphene sandwich structure (3) comprises two single-layer graphene and diaphragm paper arranged between the two single-layer graphene; the diaphragm paper is soaked in electrolyte, and each single-layer graphene is respectively connected with a bias voltage.
6. The graphene-based transmissive dynamically tunable flexible frequency selective wave absorber of claim 5, wherein: the electrolyte layer is formed by mixing diethyl methyl phthalate, trifluoromethanesulfonimide and Tf2N ionic liquid.
7. The graphene-based transmissive dynamically tunable flexible frequency selective wave absorber of claim 1, wherein: the outer diameter r of the multilayer graphene layer (11)
13 mm, inner diameter r
22 mm, the length l of each metal arm (12) is 4.97mm, and the gap width w
10.5mm, and an arm length width excluding a slit width is w
21 mm; the metal frequency selective surface layer (5) is a complementary annular periodic structure formed by etching a copper sheet with the thickness of 10 microns, and the inner diameter r
35.14mm, outer diameter r
44.14 mm; the first medium layer (2) and the second medium layer (4) are both foam plates, the foam plates are made of polyethylene terephthalate, and the thicknesses of the foam plates are respectively 3 mm; the thickness of the graphene-electrolyte-graphene sandwich structure (3) is 190 micrometers; the graphene-electrolyte-graphene sandwich structure (3) is formed by processing a single-layer graphene spread on a PVC film substrate, and the thickness of the PVC film substrate is 60 micrometers.
8. The graphene-based transmissive dynamically tunable flexible frequency selective wave absorber according to any one of claims 1-7, wherein: the thickness of the wave absorber is 6 mm, the size is 27cm multiplied by 27cm, and the wave absorber comprises 18 multiplied by 18 square ring units; wherein the size of each square ring unit is 15mm multiplied by 15 mm.
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Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111987452A (en) * | 2020-09-01 | 2020-11-24 | 中国科学院光电技术研究所 | Transmission/reflection switchable and amplitude-adjustable metamaterial |
| CN113219576A (en) * | 2021-04-22 | 2021-08-06 | 桂林电子科技大学 | Near-field imaging method based on graphene-metal split ring resonator |
| CN113410648A (en) * | 2021-06-10 | 2021-09-17 | 上海交通大学 | Pass band switchable frequency selection surface based on graphene and implementation method thereof |
| CN113871895A (en) * | 2021-09-03 | 2021-12-31 | 西安电子科技大学 | Transparent wave absorber of groove type resonance layer and mesh floor |
| CN114614266A (en) * | 2022-05-11 | 2022-06-10 | 成都飞机工业（集团）有限责任公司 | X-band-pass absorption and transmission integrated frequency selective surface structure |
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2019
- 2019-09-19 CN CN201910886991.0A patent/CN110783714A/en active Pending
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111987452A (en) * | 2020-09-01 | 2020-11-24 | 中国科学院光电技术研究所 | Transmission/reflection switchable and amplitude-adjustable metamaterial |
| CN113219576A (en) * | 2021-04-22 | 2021-08-06 | 桂林电子科技大学 | Near-field imaging method based on graphene-metal split ring resonator |
| CN113410648A (en) * | 2021-06-10 | 2021-09-17 | 上海交通大学 | Pass band switchable frequency selection surface based on graphene and implementation method thereof |
| CN113871895A (en) * | 2021-09-03 | 2021-12-31 | 西安电子科技大学 | Transparent wave absorber of groove type resonance layer and mesh floor |
| CN114614266A (en) * | 2022-05-11 | 2022-06-10 | 成都飞机工业（集团）有限责任公司 | X-band-pass absorption and transmission integrated frequency selective surface structure |
| CN114614266B (en) * | 2022-05-11 | 2022-08-12 | 成都飞机工业（集团）有限责任公司 | X-band-pass absorption and penetration integrated frequency selective surface structure |
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