PHYSICAL AND GEOMETRICAL OPTICS

This chapter presents the details of the physical optics approximation for PEC surfaces. The phenomena of electromagnetic wave radiation, propagation, reflection, and transmission exhibits a highly localized character. Such local properties exhibited by high‐frequency waves form the basis of the method of geometrical optics (GO). The GO ray field was developed based on a geometrical construction for energy transport along ray paths, and the local plane wave behavior for point‐to‐point transformation from an initial wavefront to a succeeding wavefront. An asymptotic solution is developed which remains uniformly valid across smooth caustics of GO rays that are reflected from 2‐D and 3‐D boundaries which exhibit concavity, or even a point of inflection.