Effective inductances of periodic perforated metal plates for predicting microwave shielding effectiveness

This paper presents new analytical expressions for the effective inductances of perfectly conductive metal screens that are made up of periodic sub-wavelength circular or square apertures. These expressions are applied to the prediction of the shielding effectiveness (SE) of arrays when excited by oblique incidence plane waves below the cut-off frequency, while taking into account the effect of plate thickness. A new transformation model of two arrays with different hole shapes, assuming the SE as a constraint is proposed. The inductance-based modeling is applied to circular and square pattern configurations in the gigahertz frequency range. The good accuracy of the proposed formulations is demonstrated by comparing the obtained shielding performances with the reference values given by numerical codes or experimental tests. These formulations are easy to use and can provide reliable predictions of the SE of metal screens with periodic sub-wavelength apertures.