The prediction of shielding effectiveness of the rectangular enclosure with complex apertures based on the BLT equation

In this study, a generalized BLT equation based on EMT is proposed to predict the SE of the rectangular enclosure with complex apertures. Aperture structures are decomposed into rectangular units, with equivalent impedances computed using Robinson's coplanar stripline model or Nie's capacitive-inductive diaphragm model. The Robinson model considers the influence of eccentric apertures by introducing the aperture position factor and takes into account the high-order modal effect and the SE prediction from any observation point. The results show that the Robinson model performs better than the Nie model in the high-order modes, both of which are effective under the main mode conditions, and the Nie model is more adaptable to the aspect ratio of the aperture. The effectiveness of this method in SE prediction of the rectangular enclosure with complex apertures is verified by comparison with CST Studio Suite.