Electromagnetic Wave Absorbing Metamaterial Based On Silicon Carbide/Carbon Foam

The demand of high-performance absorbing materials is increasing for the wide applications of electromagnetic technology in civilian life and for the rapid development of radar detection system in the military.However,conventional electromagnetic wave absorbing materials often suffer from excessive thickness,narrow bandwidth,complex design,poor service performance,and heavy weight,which significantly limit their future applications.Therefore,the development of highly efficient electromagnetic wave absorbing materials becomes an urgent need.Porous materials are well-known for lightweight,efficient,and broadband microwave absorption properties.Silicon carbide/carbon foam materials,as a typical porous material that has excellent environmental stability and mechanical properties,have been attracting intensive attentions.Metamaterial have been studied by many researchers owning to its unique physical effects,flexible design,and excellent absorber actions.One could precisely manipulate electromagnetic waves by modifying the basic structural unit of metamaterial.In this work,we use silicon carbide/carbon foam material in tandem with the design concept and method of metamaterial to study high efficient electromagnetic wave absorbing materials.First,we produce the silicon carbide/carbon foam material using template method.The physical parameters including the material composition,microstructure,and conductivity electromagnetic parameters of the silicon carbide/carbon foam material were measured.The effect of structure parameters of the silicon carbide/carbon foam material on electromagnetic wave absorption properties were studied with a simulation method based on tetrakaidecahedron model.The simulation results show that the structure dimension of the silicon carbide/carbon foam material has a great influence on the absorption performance,and that the unique electromagnetic properties of the silicon carbide/carbon foam material are attributed to impedance matching,interfacial polarization,and scatting effect.Then,all-dielectric radar absorbing array metamaterial and radar absorbing metamaterial combined with metal are created via simulation and experimentation.The metamaterials bases on the silicon carbide/carbon foam material.The changing laws of the effect on absorption performances due to the sub-wavelength size of absorbing metamaterials were studied.The physical absorption mechanisms of absorbing metamaterials are investigated by the electromagnetic field distribution,impedance analysis and equivalent circuit method.Two optimized radar absorbing metamaterials with excellent absorption properties were conceived,along with investigating their mechanical behaviors and thermal stability.Result shows that the comprehensive performance of two kind radar absorbing metamaterials are highly competitive to other absorbing materials.The design methods proposed in this work are useful in the design of other high-performance absorbing material.Finally,our study provides two testing methods,including time domain method and the diagonal of metal plate vertical method,for oblique incidence performance of backscattering to satisfy the factual requirements of absorbing materials.The two testing methods are proved simple and reliable.The oblique incidence performance of backscattering for the electromagnetic wave absorbing materials which were investigated in our work were characterized.The results indicate that the electromagnetic wave absorbing materials which were studied in this work have excellent oblique incidence performance of backscattering in a wide frequency band.In summary,through experiment and simulation,we investigated the porous effect and the intrinsic electromagnetic properties of the silicon carbide/carbon foam material,and combine it with metamaterial design to set up the design criteria for electromagnetic wave absorbing silicon carbide/carbon foam material-based metamaterial.The physical absorption mechanism is also proposed.The design methods,preparation methods,and characterization techniques of two high-performance absorbing metamaterials are established.The findings in this work can be considered as an effective supplement to current electromagnetic wave absorbing theories and as a solution to solve the problems of absorbing materials design.