Novel Analytical Formulation for Shielding Effectiveness Calculation of Lossy Enclosures Containing Elliptical Apertures

This paper presents a new analytical formula to evaluate the shielding effectiveness (SE) of a lossy rectangular enclosure with elliptical and/or circular apertures excited by an external plane wave. On the basis of circuit model theory and Bethe theory of small holes, we extended Yin's model to account for apertures of elliptical shapes. The hole is then treated as a transmission line with an intrinsic impedance depending on its polarizability. The model takes easily into account higher order resonant modes. For validation, a commercial software is employed and enclosures with different size and apertures are studied. The proposed model shows accurate results in good agreement with the full wave simulation ones.