Study On Metamaterial Wideband Absorbers And Applications

With the development of science and technology,it is convenient to use various electronic devices for us in daily life.However,the electromagnetic environment is deteriorating.Absorbing materials become an effective way to solve the problem of electromagnetic pollution.In the field of civil and military,absorbing materials are widely used.Metamaterial absorbers had been developed rapidly and had been a hotspot in the field of electromagnetics,since it was proposed in 2008.Firstly,this dissertation introduces the classification,research background and significance of wave-absorbing materials,and introduces the development of metamaterial absorbers at home and abroad in detail.This dissertation summarizes the development of metamaterial absorbers and introduces the impedance matching theory,the multi-layer interference theory and the effective medium theory,which provides the theoretical basis for our design.Based on those absorbing theories,this dissertation proposes a three-layer broadband metamaterial absorber with an overall thickness of 3.8mm.The absorptivity of the absorber is more than 90% in the frequency range of 7.0GHz-37.4GHz.The absorber has good polarization-insensitiveness and wide incident angle stability.The principle of its absorption is analyzed through the equivalent circuit analysis,surface current distribution analysis,equivalent impedance and loss analysis.The absorptivity of this design is verified by experiments.Radar cross section(RCS)is reduced by using the broadband metamaterial absorber in this dissertation.The broadband metamaterial absrber has a significant RCS reduction effect in both planar and curved surfaces,with respect to the same size of perfect electric conductor(PEC).Finally,for a specific application,a two-layer transparent metamaterial absorber is designed in this dissertation.The overall thickness of the design is 3.8mm and the absorptivity is more than 90% in the frequency range of 6.8GHz-19.6GHz.The absorber has good polarization-insensitiveness,wide incident angle stability and high transparency.The transparent soda-lime glass and indium tin oxide(ITO)film were used to design a transparent metamaterial absorber.Then,the principle of its absorption is analyzed through the equivalent impedance analysis,surface current distribution analysis,loss analysis and so on.The absorptivity of this design is verified by experiments.