Investigation On The Absorber Based On Graphene Frequency Selective Surface

Graphene is a new nanomaterial with excellent electrical,mechanical and optical properties,etc.The theory related to graphene has been well studied in the scientific community,and the graphene devices are drawing much attention,including graphene mmodulator,graphene absorber,and graphene antenna,etc.On the other hand,the protection of electromagnetic radiation,cloaking,radar,communication technology and other fields need the good performance of the absorber,whose rate is high,with wide absorption frequency,low profile,less layers and not sensitive to incident angle.As the conductivity of graphene is affected by electromagnetic bias and chemical doping,thus affecting the surface impedance and changing the resonant frequency of the absorber,graphene can be used to design adjustable absorbers.This paper is to design graphene absorber with superior performance by using tuneable graphene frequency selective surface(FSS).The main contribution of this work is summarized as follows:1.THz ultra wideband absorber based on graphene FSS.First,the analytical model of graphene patch FSS and graphene plane is studied,and the impedance and transmission characteristics are analyzed.The equivalent circuit model of graphene patch FSS absorber is established,and the mechanism of absorption peakis studied.The paper gives the design method of ultra wideband terahertz absorber.By adjusting the chemical potential of graphene,the tunability is achieved.And the equivalent circuit theory is validated by the simulated results of full-wave simulation software,HFSS.2.The microwave frequency ultra-wideband absorber based on graphene FSS.First,the equivalent circuit model of the metal graphene absorber is studied.Then the paper put forward the non-uniform dielectric graphene absorber of double Minkowski loops,the absorption bandwidth of which is twice the graphene absorber of double square loops.In order to enhance the absorption of complex structure with oblique incidence,a cross graphene absorber is explored,the absorption bandwidth of which has been further improved.Then,the grid graphene absorber is designed which has simple structure and is relatively easy to be fabricated.The prototypes of graphene absorber are proposed.The first one is with low profile and insensitive to the incident angle.The absorption bandwidth of the second one is further improved to 87.5 GHz.The absorption principle is explained by the interference theory,verified by the simulated results.Ultra-wideband absorbers are designed using graphene FSSs for terahertz and microwave applications.The mechanism of absorption is explained with the equivalent circuit model and the interference theory.The performance of absorbers is analyzed,which has been verified by the simulated results.