Broadband multilayer electromagnetic wave absorber designed with high storage and low loss silicone rubber-based RGO@SiO2 dielectric materials

Abstract

Electromagnetic wave absorbing materials with wide absorbing frequency band can make flight equipment avoid radar tracking, which is the need of current national defense military field. Dielectric materials have attracted much attention in recent years because of their stability in high temperature and corrosive environment. The purpose of this paper is to prepare dielectric absorbing medium with lower thickness and wider absorbing frequency band. Firstly, the theoretical value of −10 dB reflection coefficient of dielectric material at 2 mm thickness is derived, and the RGO@SiO₂ absorbing material is prepared based on this result. Then, the effect of different substrates on the absorbing properties was compared, and the silicone rubber based RGO@SiO₂ absorber was prepared. Finally, a 3-layer impedance gradient absorbing structure is designed by using genetic algorithm toolbox and reproduced experimentally. When the thickness of the three-layer structure is 4.2 mm, the electromagnetic wave absorption bandwidth of the three-layer structure optimized by genetic algorithm reaches 7.46 GHz. It is proved that the structural design of high dielectric real part and low dielectric virtual part can effectively improve the absorbing properties of materials, and provide a convenient way to improve the absorbing properties of dielectric materials.