A higher-order mode transmission line model of the shielding effectiveness of enclosures with apertures

The development of efficient phenomenological models which give accurate estimates for the coupling of electromagnetic energy through apertures and into enclosures is important for the EMC design of almost all electronic sub-systems. It has been previously shown that a simple analytical transmission line formulation gives good predictions of the shielding effectiveness of a rectangular enclosure with apertures. In this work the model is extended to include higher-order transverse electric (TE) and transverse magnetic (TM) cavity modes in the transmission line (TL) model. The loading effect of electronic components within the enclosure is modelled by the introduction of losses. The model remains very simple and computationally efficient. The finite difference time-domain (FDTD) method is used to validate the results