A Generalized Physical Optic-Based Diffraction Mechanism Analysis of Transient Scattering From Perfectly Conducting Surfaces

This paper presents a general quasi-analytical analysis of time domain (TD) electromagnetic (EM) scattering from a perfecting conducting object when it is illuminated by the radiation of a relatively arbitrary EM source with a transient-step TD response. In particular, the EM scattering mechanism is interpreted by using TD physical optic (PO) approximation to result in a contributing (integration) contour for the radiation integral. A fast numerical algorithm is also developed to find the EM scattering field. This TD-PO solution can be further applied via a time convolution to derive the early-time transient fields scattered from the same scatterer when it is illuminated by a realistic astigmatic finite-energy pulse. Practical numerical examples are presented to demonstrate the physical phenomenon of scattering mechanisms.