Research On The Structural Design And Characteristics Analysis Of Terahertz Absorber Based On Graphene

In recent years,the applications of graphene have become more and more widespread,for example,graphene batteries,graphene folding screens and graphene optical devices have become increasingly common on the market.Graphene can excite surface plasmons in the terahertz and mid-infrared bands.So graphene optical modulators,antenna arrays composed of graphene and graphene absorbers have achieved certain research results.Terahertz waves can be widely used in medical devices,security inspection and military aspects.Hence,the application of graphene in terahertz band has a certain practical value.This article mainly studies the design and characteristics analysis of graphene-based terahertz absorbers,and proposes graphene-based narrowband absorbers and graphene-based wideband absorbers,respectively.The simulation results for the narrow-band absorber prove that the absorption rate can be as high as 99.99% and the perfect absorption characteristics are achieved,by changing the structural parameters.The absorber has polarization independent and large angle absorption characteristics due to its highly symmetrical structure.More importantly,the absorption efficiency and bandwidth can be dynamically adjusted by changing the chemical potential of graphene without changing the structural parameters.However,the bandwidth of this absorber is only 2.22 THz under ideal conditions,and this narrow-band absorber is not conducive to further expanding applications.Next,an oblique 8-shaped ultra-wideband absorber and a stepped ultra-wideband absorber based on graphene metamaterials are proposed.Due to the periodic unit cell,the metamaterial absorber has a wide bandwidth and is easier to achieve perfect absorption characteristics.It can be seen from the simulation results that the oblique 8-shaped ultra-wideband absorbers has an ultra-high bandwidth of up to 7.4 THz,which makes it have wider application valuable in the terahertz band.The large angle absorption characteristics and polarization independence of the absorber further boost its practical application value.Adjusted by structural parameters,the bandwidth with absorption rate of the absorber larger than 90% is 3.85 THz.The maximum absorption rate is as high as 99.99% and the absorber actualizes perfect absorption characteristics.The bandwidth of the stepped ultra-wideband absorber can reach 5.885 THz,and the absorption efficiency of 94.75% can be achieved by adjusting the length and width of the rectangular.The absorbers proposed in this paper can use graphene's electrical adjustable characteristics to adjust its absorption efficiency and bandwidth,thus its practical application value is greater.