Tunable Absorber Based On Resonant Graphene Rings

With the development of terahertz technology,there is a continuous emergence of the devices for absorbing terahertz waves.However,the existing terahertz absorbers have the problems of single absorption frequency and relatively small tuning depth with its large size as well as limited electromagnetic properties,which makes it necessary to improve the integration of absorbing devices by searching a smaller size of the adjustable wave device.Consequently,the graphene-based nano-sized absorber is introduced,which can absorb terahertz wave adjustably,making up the shortcomings of the early absorber,and it is widely used in electromagnetic wave absorbers.Graphene has significant light,electricity,force,heat,magnetic properties and its surface conductivity can be dynamically regulated by voltage control or chemical doping.Additionally,graphene supports surface plasmon resonance in the terahertz band,The specific structure of graphene can selectively diffuse and absorb the incident electromagnetic waves and enhance the local electric field intensity.Therefore,the adjustable wave absorber based on graphene is proposed and it can realize the tunable single frequency,dual frequency and multi-band absorption enhancement by changing the structural parameters and material parameters of the model.In this paper,the graphene absorber is modeled and simulated,and then the absorption curve of the graphene absorbing structure is calculated by frequency domain finite integral method.Finally,the tuning absorption effect of concentric rings,eccentric rings,open rings and superposition models is systematically studied.Our simulation results are shown that the coupling of the concentric rings can realize the absorption of the double band,and the gap of the open loop can adjust the absorption of the multi-band.Moreover,the superposition model can realize the linear superposition of the absorption peak.It also suggests that the graphene structure not only can resonate with the incident electromagnetic wave to enhance the absorption of the electromagnetic wave around the absorbing material,but also can adjust the absorption wavelength by change the structural parameters.In addition,the paper also discusses the dynamic control of the absorption performance of graphene based chemical potential.In short,the results in this paper provide useful theoretical basis and new ideas for the design of tunable absorbing devices based on graphene structure,and it is expected to play a role in tunable electromagnetic wave absorbing materials.