Electromagnetic interference from shielding effectiveness of a rectangular enclosure with apertures - circuital approach, FDTD and FIT modelling

Apertures in a rectangular enclosure can be the coupling path of electromagnetic interference. This paper is devoted to the development of approximating phenomenological models in order to estimate the electromagnetic energy coupling through apertures into enclosures. The effect of apertures on shielding effectiveness (SE) of the enclosure is studied with both circuit modelling method and the finite-difference time-domain (FDTD) method. The results of SE predictions obtained by the analytical formulation and FDTD method are compared and validated with full-field simulations using the software CST/EMC. The software code is based on the finite integration technique. The investigation includes accurate calculation of both magnetic and electric shielding as a function of frequency, enclosure dimensions, apertures shapes, position within the enclosure, plane wave incidence mode and the loaded aperture approach.