A new approach to predict shielding properties of layered nonlinear sheets

A layered shield constituted by a first linear conductive sheet and a second nonlinear ferromagnetic sheet is considered. The field source is modelled by a transverse plane wave having a vertical polarization. The transmitted EM field is evaluated by developing a time-domain procedure. The linear sheet is represented by an equivalent field source and an equivalent input impedance, in analogy with the Thevenin approach in the transmission line theory. The analysis of the EM field propagation through the nonlinear layer is performed by using a numerical procedure based on the finite-element method. Shielding performances of different configurations including saturable ferromagnetic materials are presented