Study of the electromagnetic shielding effectiveness of perforated rectangular enclosure with external waveguide based on equivalent circuit method

Abstract

ABSTRACTAn analytical model based on the equivalent circuit method is presented to predict the electromagnetic shielding effectiveness (SE) of perforated metallic rectangular enclosure with external waveguide. In this model, the electrically small aperture is represented by a four-terminal network, and the external waveguide and enclosure are modeled as transmission line. By this way, the SE of any position of the enclosure under planewave illumination can be calculated fast and accurately over a wide frequency range (0 ~ 3 GHz). Simulation results of the proposed model are in accord with that of the transmission line matrix method, which verifies the accuracy and reliability of the model. The shielding characteristics of the perforated enclosure with external waveguide are also analyzed. The effects of parameters of aperture position, observation point position, and external waveguide length are discussed in detail. Simulation results show that the external waveguide can effectively improve the SE of the enclosure with aperture. What’s more, the shielding performance of perforated enclosure with external waveguide outperforms the perforated double-layer enclosure in some cases. For a certain length of the waveguide, the longer the edge of aperture which is perpendicular to the direction of the electric field is, the worse the shielding effect of the external waveguide on the enclosure becomes. The SE of the enclosure increases with increase of the length of the external waveguide.