EVALUATION OF SHIELDING EFFECTIVENESS OF RECTANGULAR ENCLOSURE WITH MULTIPLE APERTURES USING TRANSMISSION LINE MODEL

The electrical and magnetic shielding effectiveness of a metallic shield perforated with numerous apertures is evaluated in this work using the Transmission Line Method (TLM). Here an appropriate admittance that takes the mutual coupling between the apertures into account is considered as to represent the array of apertures. The fundamental formulas are included to deal with the case of a rectangular enclosure with numerous small rectangular apertures in this model. The electric and magnetic shielding effectiveness are compared in this paper. The observation points are taken along one of the rectangular enclosure dimension i.e., depth of the enclosure and then observed the each point for the shielding effectiveness of both electric and magnetic fields. Shielding effectiveness is calculated for the oblique incidence of single and multiple apertures. Simulation results demonstrate that: lower frequencies display better shielding than higher frequencies; the effectiveness of shielding of a single hole is worse than of a multi-hole for identical areas. The electric shielding effectiveness increases continuously with the angle of incidence and the magnetic shielding effectiveness decreases continuously with the angle of incidence.