Analytical formulation for shielding effectiveness calculation of a lossy enclosure containing holes

This paper presents an entirely analytical formula to determine the electromagnetic field inside a lossy rectangular box containing apertures on its front face. On the basis of circuit model theory we derived an extremely fast technique to include conductor losses into the model. A surface impedance boundary condition is introduced to deal with lossy conductive walls of the cavity. The model takes easily into account higher order resonant modes and improve the prediction of the shielding effectiveness. For validation, a commercial software is employed and enclosures with different conductivities and apertures are studied. The proposed model shows accurate results in very good agreement with the full wave simulation results.