Design and measurement of structural absorbing material with multilayer

The research of broadband absorbing materials is of great importance in engineering application. In this paper, a broadband structural absorbing material with multilayer is studied. Different proportions of graphite and iron powders added into the cement materials, which forms the absorbing material with a multilayer sandwich structure. Firstly, in order to measure this multilayer structural absorbing material, we developed the original method of measuring electromagnetic parameters,which is independent of the reference plane. A novel nonlinear equation for parameter extraction is presented. Compared with the original equation, the convergence rate of the iterative solution is improved. Secondly, a formula for choosing the initial confidence region of the nonlinear equation is given. At last, the equivalent electromagnetic parameters of the multilayer structure absorbing material were measured and analyzed, and the efficient permittivity and permeability were obtained.