Study On The Dynamic Tunable Absorber Of Graphene Metasurface

As a composite material of periodic unit structure with special electromagnetic properties,electromagnetic metamaterial.It is a unique periodic structure of human modeling.It has novel characteristics different from traditional natural materials.It can adjust and control the geometric parameters of periodic unit structure artificially,so as to realize the electromagnetic function of far more than natural materials.Electromagnetic meta material absorber is a subclass of electromagnetic meta material.As the name implies,the absorber is a kind of device that consumes the incident electromagnetic wave,and it is very useful in our real life,and has attracted the attention of a large number of researchers.In this paper,we first introduce the history and current situation of the meta material absorbers,and focus on the tunable terahertz meta material absorbers.Then,based on graphene with excellent electromagnetic properties,we design a tunable double side band Meta material absorber and a single graphene wide range tunable meta material absorber The conductivity model of graphene is established,and the absorption performance of the absorber is studied,and the physical absorption mechanism of the absorber is analyzed from multiple angles.The main research contents are as follows: Firstly,a dual band dynamic tunable absorber based on graphene meta surface is designed in 6-20 THz.The results show that the absorption efficiency of the absorber is over 98%.At the same time,the full width of the half peak of absorption efficiency is 3.87 thz.Moreover,when the incident angle is 75 °,the absorption efficiency can still be maintained over 85%.In addition,by changing the Fermi energy level of graphene,we can achieve dynamic tuning and maintain ultra-high absorption efficiency.Then,a dynamic tunable graphene absorber with periodic structure composed of graphene and cross channel medium is proposed.The results show that the absorption efficiency of the absorber is close to 100%,By changing the chemical potential from 0.4ev to 0.8ev,the absorption peak can be adjusted from 6.4thz to 8.75 thz,13.1thz to 17.85 thz,with a very wide adjustable range.The simulated electric field and power loss density distribution of resonance frequency point are analyzed.In addition,the transverse electric(TE)and transverse magnetic(TM)modes have the geometric rotational symmetry of the unit structure,so the absorber is not sensitive to polarization.In addition,by changing the chemical potential of graphene,the absorption characteristics of the absorbers can be dynamically adjusted.The simulation results also show that the absorptivity of the material is sensitive to the incident angle of THz wave,and it can be used as an angle sensor in the future.