CN113410648B - Graphene-based passband switchable frequency selection surface and implementation method thereof - Google Patents
Graphene-based passband switchable frequency selection surface and implementation method thereof Download PDFInfo
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- H01Q15/0006—Devices acting selectively as reflecting surface, as diffracting or as refracting device, e.g. frequency filtering or angular spatial filtering devices
- H01Q15/0013—Devices acting selectively as reflecting surface, as diffracting or as refracting device, e.g. frequency filtering or angular spatial filtering devices said selective devices working as frequency-selective reflecting surfaces, e.g. FSS, dichroic plates, surfaces being partly transmissive and reflective
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- H01Q15/0006—Devices acting selectively as reflecting surface, as diffracting or as refracting device, e.g. frequency filtering or angular spatial filtering devices
- H01Q15/0013—Devices acting selectively as reflecting surface, as diffracting or as refracting device, e.g. frequency filtering or angular spatial filtering devices said selective devices working as frequency-selective reflecting surfaces, e.g. FSS, dichroic plates, surfaces being partly transmissive and reflective
- H01Q15/0026—Devices acting selectively as reflecting surface, as diffracting or as refracting device, e.g. frequency filtering or angular spatial filtering devices said selective devices working as frequency-selective reflecting surfaces, e.g. FSS, dichroic plates, surfaces being partly transmissive and reflective said selective devices having a stacked geometry or having multiple layers
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Abstract
A graphene-based passband switchable frequency selective surface and a realization method thereof comprise: the dielectric layers and the metal-graphene mixed structure resonator array layers are symmetrically arranged on two sides of the metal structure layer from inside to outside; the metal-graphene mixed structure resonator array layer is formed by arranging a plurality of basic units obtained by adopting a metal-graphene mixed structure processing technology, and specifically is a metal-graphene mixed cross structure with a graphene rectangular sheet loaded at the tail end. According to the Aperture Coupling Resonator (ACR) basic theory, the designed frequency selection surface works in a terahertz frequency band, and the terahertz frequency band has the advantage that the passband working state can be switched.
Description
Technical Field
The invention relates to a technology in the field of terahertz communication, in particular to a switchable passband frequency selective surface based on an aperture coupling graphene resonator.
Background
In a wireless communication system, a Frequency Selective Surface (FSS) can be used as a radome, allowing reception and transmission of electromagnetic waves in a specific frequency band, i.e., the electromagnetic waves in a specific frequency band cannot be transmitted or received, in which case a pass band switchable frequency selective surface is used as the radome.
However, the drawbacks and disadvantages of the existing switchable frequency selective surfaces are: existing switchable frequency selective surfaces are mostly designed based on the forward turn-on and reverse turn-off characteristics of diodes and mostly operate in the microwave frequency band. The size and cut-off frequency of the diode limit the application of the design idea in high frequency band, for example, in terahertz frequency band, the wavelength of electromagnetic wave is shorter, even smaller than the size of the diode itself, and the switchable terahertz frequency selection surface cannot be realized by using the diode.
On the other hand, graphene is an atomic-thickness honeycomb two-dimensional material composed of carbon atoms, and has excellent electromagnetic properties with tunable surface conductivity. The graphene is in a high-resistance state when the electrochemical potential is low and in a low-resistance state when the electrochemical potential is high, and the carrier concentration can be changed by applying direct-current voltage bias to the graphene, so that the electrochemical potential is changed, and the change of the conductivity is realized. Therefore, the graphene material can be used in the design and implementation of switchable frequency selective surfaces, and no report of switchable frequency selective surfaces of graphene exists at present.
Disclosure of Invention
Aiming at the defects in the prior art, the invention provides a graphene-based passband switchable frequency selective surface and an implementation method thereof.
The invention is realized by the following technical scheme:
the invention relates to a terahertz passband switchable frequency selective surface based on an aperture coupling graphene resonator, which comprises: the dielectric layers and the metal-graphene mixed structure resonator array layers are symmetrically arranged on two sides of the metal structure layer from inside to outside.
The metal-graphene mixed structure resonator array layer is formed by arranging a plurality of basic units obtained by adopting a metal-graphene mixed structure processing technology, and specifically is a metal-graphene mixed cross structure with a graphene rectangular sheet loaded at the tail end.
The metal structure layer on periodic settings round hole group, this round hole group includes that the position of four round holes and round hole corresponds with the position of graphite alkene rectangle piece in the metal-graphite alkene mixed structure syntonizer array layer, arouse electromagnetic resonance after the electromagnetic wave gets into one side metal-graphite alkene mixed structure syntonizer array layer, the electric field distributes at the both ends of the metal-graphite alkene mixed cross structure syntonizer along the direction of polarization, cross syntonizer produces the coupling through terminal graphite alkene piece, the electromagnetic wave sees through the circular aperture on the intermediate level structure, upper strata and dielectric layer reachs opposite side metal-graphite alkene mixed structure syntonizer array layer, cross syntonizer radiates out the electromagnetic wave.
The passband switchable frequency selective surface based on the aperture coupling graphene resonator is realized by a metal-graphene mixed structure processing technology, and comprises the following steps:
step 6, preparing uniform metal on the upper surface of the dielectric layer, and completing the imaging of the intermediate metal structure;
step 7, spin-coating a dielectric layer film and baking to obtain a dielectric layer;
step 8, finishing the processing of metal patterns in the top layer metal-graphene mixed structure resonator array on the upper surface of the dielectric layer;
step 9, spin coating a filling medium, baking, polishing and grinding until the surface of the metal pattern is exposed;
step 11, spin-coating a dielectric film and baking the dielectric film to be used as a graphene pattern protection layer; and (4) performing debonding on the temporary bonding glue, and taking the prepared frequency selection surface from the temporary slide.
Technical effects
The invention integrally solves the defects that the prior art works in lower frequency bands such as microwave frequency band and the like, and cannot realize performance regulation by using temperature, thereby being not beneficial to stable work of the system. Compared with the prior art, the terahertz frequency band switchable frequency selective surface is realized on the basis of the aperture coupling theory in the terahertz frequency band. Due to the unique electric adjustable property of the graphene, when an external electric field bias is applied to the graphene, the electrochemical potential and the surface conductivity of the graphene are changed, so that the aperture coupling strength is changed, and the passband working state of the frequency selective surface has adjustability. And a metal-graphene hybrid structure processing technology is provided to ensure the feasibility of processing the proposed reconfigurable frequency selective surface.
Drawings
FIG. 1 is a schematic view of the overall structure of the present invention;
fig. 2 is a partially enlarged view of a top metal-graphene hybrid resonator array 1 and a bottom metal-graphene hybrid resonator array 5 according to the present invention;
FIG. 3 is a partial enlarged view of the middle metal structure 3 according to the present invention;
fig. 4 is a schematic structural diagram of a basic constituent unit 11 of a top metal-graphene hybrid resonator array 1 and a bottom metal-graphene hybrid resonator array 5 in the present invention;
FIG. 5 is a schematic structural diagram of a basic unit 31 of the middle metal structure 3 in the present invention;
fig. 6 is a schematic view of a process flow of a metal-graphene hybrid structure proposed in the present invention;
fig. 7 is an equivalent circuit of a passband switchable frequency selective surface based on an aperture coupled graphene resonator in the present invention;
fig. 8 is a fitting situation of a full-wave simulation result of a reflection coefficient and a transmission coefficient of the passband switchable frequency selective surface in an off state (chemical formula is 0.1eV) and an equivalent circuit calculation result based on the aperture-coupled graphene resonator according to the present invention;
fig. 9 is a fitting situation of a full-wave simulation result of a reflection coefficient and a transmission coefficient of a passband switchable frequency selective surface in an on state (chemical formula is 1eV) and an equivalent circuit calculation result based on an aperture-coupled graphene resonator according to the present invention;
Detailed Description
In the embodiment, the frequency selection surface of the graphene-based aperture coupling resonator has a multilayer structure, the upper layer and the lower layer are identical metal-graphene hybrid structure resonators, coupling is generated between the upper layer and the lower layer through the aperture of the middle layer, and according to a coupling topology, the two layers of resonators can generate electric coupling and magnetic coupling through the aperture in the middle. Wherein: the position of the aperture determines whether electrical or magnetic coupling prevails.
In consideration of the characteristics of graphene, the graphene is loaded at the coupling aperture, and when the electrochemical potential of the graphene is adjusted, the conductivity of the graphene changes, and the electric field distributed on the graphene also changes, so that the coupling strength of the upper layer and the lower layer and the coupling aperture changes accordingly.
In summary, the graphene is loaded at the coupling aperture, and the external bias voltage of the graphene is changed to change the electrochemical potential of the graphene, so that the coupling strength can be controlled, and the opening and closing of the pass band in the designed aperture coupling frequency selection surface frequency response characteristic are realized.
According to the coupled filter theory, the aperture coupling structure can produce a narrow band frequency response. Two transmission zeros may be generated within the pass band, where: one transmission zero is caused by the resonance of the resonator itself and the other transmission zero is caused by the coupling of the resonator with the aperture.
The intrinsic mechanism of the aperture-coupled frequency selective surface can be better analyzed using an equivalent circuit. In an equivalent circuit, the upper layer and the lower layer of the metal-graphene mixed resonator are composed of two L paths0+LG、R0+RGAnd C0A series resonant circuit representation, wherein: l is a radical of an alcohol0Is a resonator metal part inductor, LGIs a graphene partial inductance, R, of the resonator0Being a resonator metal part resistance, RGIs a graphene partial resistance of the resonator, C0A metal part capacitor of the resonator; the coupling aperture of the middle layer is formed by an equivalent aperture inductor LaPore diameter resistance RaAnd aperture capacitance CaA parallel resonant circuit representation; the medium between the coupling aperture and the resonator is represented by two short transmission lines having a wave impedance of
Wherein: epsilonrIs the relative dielectric constant of the medium. In the invention, the aperture is positioned at the tail part of the metal-graphene mixed cross-shaped structure resonator, namely the position with larger electric field, and the mutual capacitor C for electric coupling between the resonators generated by the aperturemIndicating that the magnetic coupling between the two layers of resonators is negligible. The coupling between the resonator and the aperture itself is then established by a coupling capacitor Cm1And a coupling inductor Lm1And (4) showing. The input signal can reach the output end by two paths at most, and is transmitted by direct coupling through the aperture, and is coupled to the lower layer resonator after being coupled with the aperture through the upper layer resonator. Compared with direct electric coupling Cm，Cm1And Lm1The contribution to the coupling is negligible, let Cm1＝0，L m10, i.e. direct coupling is dominant.
The thinner dielectric results in a smaller electrical length of the equivalent transmission line and a L characterizing the coupling aperture due to the symmetry of the equivalent circuitaAnd CaThe influence on the resonant frequency can be ignored, and two resonant frequencies are respectively obtained by calculation based on the odd-even mode theory
It can be seen that the odd mode resonant frequency foAnd L0、LGAnd C0Related, not to CmThe influence of (a); and the even mode resonance frequency feFollowing mutual capacitance CmIs increased. Therefore, according to the filter theory, the coupling aperture can be designed, and the size of the electric coupling is controlled to adjust the even mode resonant frequency, so that the required frequency response characteristic is obtained.
The electrochemical potential of graphene can be adjusted between 0-1 eV. According to the invention, the equivalent inductance and capacitance parameters are changed by adjusting the electrochemical potential of the graphene, so that the control of the switch state of the frequency selection surface passband is realized. The invention takes two states, among them: 0.1eV represents that the graphene is in a high-resistance state, at the moment, the aperture coupling strength is low, and the passband of the frequency selection surface is in a turn-off state; and 1eV represents that the graphene is in a low-resistance state, at the moment, the aperture coupling strength is high, and the pass band of the frequency selection surface is in a conducting state.
As shown in fig. 1, for this embodiment, a switchable terahertz pass-band frequency selective surface based on an aperture-coupled graphene resonator is related to, and the switchable terahertz pass-band frequency selective surface can be applied to systems such as terahertz frequency band wireless communication and radar detection, and specifically includes: the dielectric layers 2 and 4 and the metal-graphene mixed structure resonator array layers 1 and 5 are symmetrically arranged on two sides of the metal structure layer 3 from inside to outside.
As shown in fig. 2, the resonator array layers 1 and 5 of the metal-graphene mixed structure are formed by arranging a plurality of basic units 11, and the rectangular units are obtained by adopting a metal-graphene mixed structure processing technology.
The period is arranged, and the period is 140 mu m.
As shown in fig. 4, the basic unit 11 is specifically a metal-graphene hybrid cross-shaped structure with a graphene rectangular sheet loaded at an end, and includes: a metal pattern 111, and a graphene pattern 112.
The metal pattern 111 is a cross-shaped structure, the length of the metal cross is 90 μm, and the width of the metal cross is 10 μm.
The graphene rectangular sheets are respectively located at the four tail ends of the metal pattern 111, and the length of each graphene rectangular sheet is 20 μm, and the width of each graphene rectangular sheet is 5 μm.
The dielectric layer is a dielectric film with low dielectric constant and low loss, the material of the dielectric film is preferably benzocyclobutene (BCB), the relative dielectric constant is 2.65, and the thickness is 10 mu m.
As shown in fig. 3, the metal structure layer 3 is periodically provided with circular hole groups, and the interval between the circular hole groups is 140 μm.
As shown in fig. 5, the circular hole group includes four circular holes, the positions of the circular holes correspond to the positions of the graphene rectangular sheets in the resonator array layer with the metal-graphene hybrid structure, and the diameter of the circular holes is preferably 13 μm.
As shown in fig. 6, this embodiment relates to the switchable terahertz passband frequency selective surface based on the aperture-coupled graphene resonator, which is prepared in the following manner:
step 6, as shown in fig. 6f, spin-coating a photoresist on the sample, placing a chromium mask to expose and develop the photoresist to obtain a patterned photoresist;
step 7, as shown in fig. 6g, placing the sample into a reaction furnace, etching off part of PMMA and graphene by using a Reactive Ion Etching (RIE) process, and washing off the remaining photoresist to obtain a graphene pattern in the bottom layer metal-graphene hybrid resonator array;
step 8, as shown in fig. 6h, spin-coating BCB glue, baking to 190 ℃ and curing to obtain a dielectric layer;
step 9, as shown in fig. 6i, obtaining a complete and uniform metal film, which is generally a copper film or a nickel film, by using an electron beam evaporation process;
step 11, as shown in fig. 6k, spin-coating a BCB glue, baking to 190 ℃ and curing to obtain a dielectric layer;
step 12, as shown in fig. 6l, placing a metal mask on a substrate, and obtaining a metal pattern, generally a copper film or a nickel film, in the top metal-graphene hybrid structure resonator array by using an electron beam evaporation process;
step 13, as shown in fig. 6m, spin-coating a filling material, baking and curing, and polishing until the upper surface of the metal pattern is exposed;
step 14, as shown in fig. 6n, using a PMMA assisted wet transfer process to transfer the whole graphene onto the metal pattern;
step 16, as shown in fig. 6p, placing the sample into a reaction furnace, etching off part of PMMA and graphene by using an RIE process, and washing off the remaining photoresist to obtain a graphene pattern in the top metal-graphene hybrid resonator array;
step 17, as shown in fig. 6q, spin-coating PMMA on the sample, baking and curing to obtain a protective layer;
step 18, as shown in fig. 6r, heating the sample to 235 ℃ to perform pyrolytic bonding on the temporary bonding glue, and taking down the frequency selective surface from the temporary slide to complete the preparation.
When electromagnetic waves enter the metal-graphene mixed structure resonator array layer on one side, electromagnetic resonance is excited, an electric field is distributed at two ends of the metal-graphene mixed cross-shaped structure resonator along the polarization direction, the cross-shaped resonators on two sides of the aperture are coupled through the graphene sheet at the tail end, the electromagnetic waves penetrate through the circular aperture, the upper layer and the dielectric layer on the intermediate layer structure to reach the metal-graphene mixed structure resonator array layer on the other side, and the cross-shaped resonator radiates the electromagnetic waves.
Due to the fact that the graphene has the electrical adjustable characteristic, when the electrochemical potential of the graphene is adjusted, the surface conductivity of the graphene changes, the distribution of an electric field distributed on the graphene rectangular sheet changes, and the coupling strength between the top-layer cross resonator and the bottom-layer cross resonator changes accordingly. Briefly, the coupling strength can be controlled by changing the external bias voltage of the graphene to realize the electrochemical potential change of the graphene, and then the working state of the pass band switch is controlled. When the electrochemical potential is 1eV, the graphene rectangular sheet is in a low-resistance state, the electric field distribution near the coupling aperture is strong, and the frequency selection surface works in a conducting state; when the electrochemical potential is 0.1eV, the graphene rectangular sheet is in a high-resistance state, the electric field distribution near the coupling aperture is weak, electromagnetic waves are difficult to couple through the aperture on the middle-layer metal structure, and the frequency selection surface is in a turn-off state.
As shown in fig. 7, an equivalent circuit diagram of the passband switchable frequency selective surface of the graphene resonator based on aperture coupling in the present embodiment is shown, where: caIs an aperture capacitance, LaIs an aperture inductance, RaIs the pore diameter resistance, C0Is a resonator metal part capacitor, L0Is a resonator metal part inductor, R0Is a resonator metal part resistance, LGIs a graphene partial inductance, R, of the resonatorGIs a graphene partial resistance of the resonator, CmIs a coupling capacitor; l ism1And Cm1Respectively the coupling capacitance and the coupling inductance between the resonator and the aperture itself, can be neglected.
As shown in fig. 8, a comparison graph of an equivalent circuit calculation result of a reflection coefficient and a transmission coefficient of the passband switchable frequency selective surface based on the aperture-coupled graphene resonator in a high-impedance state of graphene and a full-wave simulation result is shown in this embodiment.
It can be found that equivalent circuit calculation is well matched with full-wave simulation results, and for the equivalent circuit with the passband switchable frequency selection surface passband off state of the aperture coupled graphene resonator, the aperture capacitance C isaHas a value of 0.0177pF and an aperture inductance LaHas a value of 0.9783pH and an aperture resistance RaHas a value of 0.3977 omega, and the metal part capacitance C of the resonator0Of 0.34fF, the resonator metal part inductance L0With a value of 81.84pH, the resonator graphene partial inductance LGHas a value of 51.05pH and a total resonator resistance R0And RGTotal 106.89 omega, coupling capacitance CmThe value of (A) was 9.452 aF.
As shown in fig. 9, a comparison graph of an equivalent circuit calculation result of reflection coefficient and transmission coefficient of the passband switchable frequency selective surface based on the aperture-coupled graphene resonator in the low-resistance state of graphene and a full-wave simulation result is shown in this embodiment.
It can be found that the equivalent circuit calculation is well matched with the full-wave simulation result, and for the equivalent circuit with the aperture coupling graphene resonator having the passband switchable frequency selective surface passband conduction state, the aperture capacitance C isaHas a value of 0.1287pF, an aperture inductance LaHas a value of 0.138pH and an aperture resistance RaHas a value of 0.0564 omega, and a resonator metal part capacitance C0Has a value of 0.34fF, the resonator metal part inductance L0With a value of 81.84pH, resonator graphene partial inductance LGHas a value of 5.16pH and a resonator total resistance R0And RGTotal 2.164 omega, coupling capacitance CmThe value of (A) was 13.71 aF.
The comparison of equivalent circuit parameters of the aperture coupling graphene resonator under the states of passband switchable frequency selection surface passband on and off can find that the surface impedance of the graphene can be changed by changing the electrochemical potential of the graphene, so that the coupling strength and the equivalent circuit parameters of the aperture are influenced, and the regulation and control of the frequency response characteristic are realized. According to the calculation of a Kubo formula, the theoretical inductance ratio of graphene in a high-resistance state and a low-resistance state is 9.89, and the partial inductance L of the graphene in the resonator in the two states is obtained through calculation of an equivalent circuitGThe ratios are consistent. The equivalent parameters of the aperture can be changed by the change of the characteristics of the graphene, but the aperture inductance L in two states obtained by equivalent circuit fittingaAnd aperture resistance RaThe ratio of (1), namely the Q value of the aperture is not influenced by the resistance change of the graphene. When the characteristics of the graphene are changed, the aperture resonance frequency is basically kept unchanged, but the reactance slope parameter is greatly influenced by the state of the graphene. With the graphene switched from the low-resistance state to the high-resistance state, the metal part capacitor C of the resonator0The value of (C) is kept constant at 0.34fF, but the coupling capacitance C is kept constantmThe value of (a) was reduced from 13.71aF to 9.452aF, i.e. the coupling coefficient was reduced from 0.04 to 0.027; graphene inductor LGThe resonance frequency of the metal-graphene mixed structure resonator is reduced; graphene resistor RGThe size is remarkably increased, the current distribution of the metal-graphene mixed structure resonator is changed, the Q value is remarkably reduced, and the pass band of the frequency selection surface is turned off.
It can be seen from the above embodiments that the designed passband switchable frequency selective surface based on the aperture coupled graphene resonator has a passband center frequency of 0.88THz, a relative bandwidth of 6.7%, an in-band insertion loss in the on state of 1.74dB, an out-of-band rejection degree of greater than 30dB, an in-band insertion loss in the off state of 35dB, and an out-of-band rejection degree of greater than 25 dB.
Compared with the prior art, the embodiment realizes the passband switchable frequency selective surface based on the aperture coupling graphene resonator based on the proposed metal-graphene mixed structure processing technology, and realizes the switching characteristic of the passband working state of the frequency selective surface at 0.88 THz. The effectiveness and feasibility of the graphene used for the terahertz frequency selection surface are verified, in the embodiment, based on the aperture coupling graphene resonator, the center frequency of the switchable frequency selection surface of the passband is 0.88THz, the relative bandwidth is 6.7%, the in-band insertion loss in the on state is 1.74dB, the out-of-band rejection degree is larger than 35dB, the in-band insertion loss in the off state is 35dB, and the out-of-band rejection degree is larger than 25 dB.
Compared with the prior art, the invention realizes the switching characteristic of the working state of the passband of the frequency selective surface at 0.88 THz.
The foregoing embodiments may be modified in many different ways by those skilled in the art without departing from the spirit and scope of the invention, which is defined by the appended claims and all changes that come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.
Claims (5)
1. A terahertz passband switchable frequency selective surface based on an aperture-coupled graphene resonator, comprising: the array layer of the metal-graphene hybrid structure resonator, the dielectric layer, the metal structure layer, the dielectric layer and the array layer of the metal-graphene hybrid structure resonator are sequentially arranged from top to bottom, and the dielectric layer and the array layer of the metal-graphene hybrid structure resonator which are positioned on the two sides of the metal structure layer are symmetrically arranged;
the metal-graphene mixed structure resonator array layer is formed by arranging a plurality of basic units obtained by adopting a metal-graphene mixed structure processing technology, specifically is a metal-graphene mixed cross structure with a graphene rectangular sheet loaded at the tail end, and comprises: metal pattern and graphite alkene pattern, wherein: the graphene rectangular sheets are respectively positioned at the four tail ends of the metal pattern;
the metal structure layer is periodically provided with round hole groups, each round hole group comprises four round holes, the positions of the round holes correspond to the positions of the graphene rectangular sheets in the metal-graphene mixed structure resonator array layer, electromagnetic resonance is excited after electromagnetic waves enter the metal-graphene mixed structure resonator array layer on one side, an electric field is distributed at two ends of the metal-graphene mixed cross-shaped structure resonator along the polarization direction, the cross-shaped resonator generates coupling through the graphene sheets at the tail end, the electromagnetic waves penetrate through the round holes, the metal-graphene mixed structure resonator array layer on one side and the dielectric layer to reach the metal-graphene mixed structure resonator array layer on the other side, and the cross-shaped resonator radiates the electromagnetic waves;
the diameter of the round hole is 13 μm.
2. The switchable terahertz pass-band frequency selective surface based on an aperture-coupled graphene resonator according to claim 1, wherein the cross-shaped structure has a length of 90 μm and a width of 10 μm;
the length of the graphene rectangular sheet is 20 micrometers, and the width of the graphene rectangular sheet is 5 micrometers.
3. The switchable terahertz pass-band frequency selective surface based on the aperture-coupled graphene resonator according to claim 1, wherein the dielectric layer is a dielectric film with low dielectric constant and low loss, the dielectric film is made of benzocyclobutene, the relative dielectric constant is 2.65, and the thickness is 10 μm.
4. The switchable terahertz pass-band frequency selective surface based on aperture-coupled graphene resonators as claimed in claim 1, wherein the group of circular holes are spaced at 140 μm intervals.
5. The switchable terahertz pass-band frequency selective surface based on the aperture-coupled graphene resonator as claimed in any one of claims 1 to 4, which is realized by a metal-graphene hybrid structure processing technology, and comprises the following steps:
step 1, spin-coating a temporary bonding adhesive on a substrate serving as a temporary slide and baking to obtain a uniform coating;
step 2, finishing the processing of metal patterns in the bottom layer metal-graphene mixed structure resonator array on the upper surface with the coating;
step 3, spin-coating a filling medium, baking, and polishing and grinding until the surface of the metal pattern is exposed;
step 4, transferring the whole layer of graphene, and finishing processing of the graphene pattern in the resonator array with the bottom layer of metal-graphene mixed structure;
step 5, spin-coating a dielectric layer film and baking to obtain a dielectric layer;
step 6, preparing uniform metal on the upper surface of the dielectric layer, and completing the imaging of the intermediate metal structure;
step 7, spin-coating a dielectric layer film and baking to obtain a dielectric layer;
step 8, finishing the processing of metal patterns in the top layer metal-graphene mixed structure resonator array on the upper surface of the dielectric layer;
step 9, spin coating a filling medium, baking, polishing and grinding until the surface of the metal pattern is exposed;
step 10, transferring the whole layer of graphene, and finishing the processing of the graphene pattern in the top layer metal-graphene mixed structure resonator array;
step 11, spin-coating a dielectric film and baking the dielectric film to be used as a graphene pattern protection layer; and (4) performing debonding on the temporary bonding glue, and taking the prepared frequency selection surface from the temporary slide.
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| CN213023815U (en) * | 2020-11-04 | 2021-04-20 | 桂林电子科技大学 | Terahertz super-surface modulator based on terahertz waveband |
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