Shielding effectiveness of a rectangular enclosure with finite wall thickness and rectangular apertures by the generalised modal method of moments

An efficient and accurate technique based on modal method of moments (MoM) is introduced, which takes into account the perforated wall thickness in the calculation of the shielding effectiveness (SE) of a rectangular enclosure. To achieve this, the modal expansion of the magnetic currents at both sides of the aperture is considered and the volume inside the aperture and the enclosure walls is represented by a proper Green´s function that is incorporated in the original modal MoM. The SE of an enclosure with single and multiple rectangular apertures with various wall thicknesses is examined. A very good agreement among the results of the proposed method and experimental results is observed. It is shown that wall thickness affects the calculated SE, and hence, the accuracy and precision of SE prediction is increased by taking it into consideration. In addition to being efficient, the method shows convergent results even for very small thicknesses.