Transient Electromagnetic Kirchhoff Diffraction by a Temporally Discontinuous Spatially Truncated Conductive Sheet

The time-domain (TD) electromagnetic (EM) plane-wave (PW) response of a time-varying (TV), conductive finite sheet is described with the aid of Kirchhoff’s approximation and the Cagniard-deHoop (CdH) technique. Closed-form analytical expressions are derived for the unit-step excitation and the jump temporal discontinuity of electric conductivity. It is explicitly demonstrated that, under Kirchhoff’s approximation, the abrupt change in the sheet’s electrical conductivity gives rise to a transverse EM (TEM) PW constituent propagating away from the sheet in the normal direction with respect to its plane. Moreover, the effect of step modulation manifests itself via diffracted cylindrical waves emanating from the sheet’s edges. Illustrative numerical examples are presented.