Analysis of shielding effectiveness of a rectangular enclosure with aperture irradiated by plane wave using the intermediate circuit model

In this paper; the problem of evaluation the shielding effectiveness of a rectangular box containing a rectangular aperture, irradiated by a plane wave is investigated. In the proposed model [1], [2] the aperture is treated as a two-wire transmission line, and the enclosure is modeled as a length of a rectangular waveguide back-ended by a short. The distribution of the electric field on the aperture is used to give a first estimate of the modal excitation of the box [1], [2]. In this work, it is our idea, to use a simple formula developed by [3] and [4] to calculate the voltage distribution on the aperture (without cavity) in order to evaluate the electric field distributed on this aperture. This approach is useful to achieve a fast evaluation of electric shielding effectiveness (SE) and magnetic shielding effectiveness (SM). The obtained results are in good agreement with the results given by other theoretical models [2], [5], also compare well with full-field simulations using the finite-difference time-domain technique (FDTD).