Calculation of complex permittivity for shielding effectiveness equivalence

In order to analyze and improve the shielding effectiveness of coating or metallic mesh, it is necessary to estimate the equivalent complex permittivity of multilayer materials based on the 3D-eIectromagnetic field simulation model or experiment results. A method is presented to calculate the complex permittivity for shielding effectiveness equivalence. Firstly, the simulation model of the multilayer material is established. After the process of wideband plane electromagnetic wave transmission, the magnitude and phase response in frequency domain are obtained. Secondly, based on the free space method, the equivalent complex permittivity of coating or metallic mesh in multilayer materials can be solved under necessary assumption. This method can be used to obtain the simplified model (even change the thickness of layer) with the same shielding effectiveness of multilayer materials, which can reduce the mesh density and the complexity in simulation. Additionally, it can be used to design the material structure that meet the shielding effectiveness requirements.