Shielding effectiveness of a metal cavity covered by a material with a medium conductivity

Abstract

The electromagnetic shielding effectiveness (SE) of a metal cavity covered by a material of medium conductivity is investigated theoretically by using an equivalent circuit method based on the transmission line and waveguide theory. The validity of the theoretical model is verified by comparison with the electromagnetic simulation software. The position effect and the resonance effect of the SE are calculated. A method for evaluating the SE of materials is suggested. With this method, the influence of the resonance effect and the position effect can be impaired greatly, also the SE of materials against plane wave can be evaluated directly.