Research On Microwave And Millimeter Wave Absorbing Technology Based On Graphene

Due to the increasing radiation pollution,microwave millimeter wave absorbing technology has been paid more and more attention in the military field and daily life.Once the traditional absorber structure is completed,it can only work at a fixed frequency or a limited frequency range,and it is difficult to achieve frequency tunability,which limits the application range of the actual life absorber.Graphene has a conductivityadjustable property.The conductivity of graphene can be controlled by chemical doping,electric field or magnetic field.This property makes graphene an important research prospect in tunable absorbing applications.Therefore,this paper mainly studies the electromagnetic absorption properties of graphene materials in microwave millimeter wave band from the perspective of simulation and theoretical analysis.The specific research work is as follows:1 ? Firstly,the electromagnetic properties of graphene are discussed,and the graphene conductivity model of microwave millimeter wave band is considered under the consideration of electric field bias.According to the mathematical expression of graphene conductivity,the relationship between chemical potential and frequency,and the equivalent surface impedance and equivalent dielectric constant of graphene and electrical conductivity were simulated in MATLAB.Provide the necessary theoretical basis for later research.2?A single-layer graphene-based absorber structure working in the microwave frequency band is proposed.Firstly,the structural parameters of the absorber were optimized,and the influence of the chemical potential change of graphene on the absorption performance of the absorber was discussed.The results show that by adjusting the graphene chemical potential,the absorption amplitude can be adjusted,and a perfect absorption of nearly 100% is achieved at 14.25 GHz.The simulation results also show that the absorber has good incident angle and polarization stability,and the working principle of electromagnetic absorption and amplitude adjustment of the absorber is explained from the perspective of current distribution.Finally,a simple broadband absorber based on single-layer graphene is proposed.The absorption rate is above 90% at 13.6GHz 42.9GHz.3? Two methods are proposed to implement a graphene-based frequency tunable absorber.One method is to use the tunable electromagnetic properties of graphene.The absorber based on the mixture structure of graphene and metal realizes the dynamic tunability of the center frequency.The chemical potential increases from 0.1eV to 0.5eV,and the absorption frequency is from 14.25 GHz.Moved to 7.62 GHz,the frequency is adjustable in the range of about 7 GHz;the other method is based on the study of the absorption characteristics of the single-layer graphene structure,using the multilayer graphene-medium layer structure cascade to achieve the center frequency dynamics.Adjustable absorber,when the number of stacked layers is increased from 1 to 3,the absorption frequency is shifted from 17.94 GHz to 5.16 GHz,achieving a frequency tuning range of approximately 12 GHz.