Geometrical optics and diffraction extracted from Physical Optics by surface to line integral reduction using modified edge representation

Equivalent Edge Currents (EECs) are widely utilized to asymptotically express the edge diffraction from the periphery of the scatterers, as in the concept suggested by Young. Authors proposed novel EECs based upon the unique concept named as Modified Edge Representation (MER), for surface to line integral reduction of Physical Optics (PO) radiation integrals. MER is based upon not only asymptotic approximation but also Stokes theorem, and is uniformly accurate at the geometrical boundaries. Moreover MER EECs are clearly defined not only at the edges but also everywhere on the scatterer surface. It comes that in MER both the diffraction and the Geometrical Optics (GO) reflection are expressed in terms of line integration of EECs along the periphery and the indentation at the reflection point, respectively. In this paper, the GO reflection is numerically compared with the MER indentation integral around the reflection point for the dipole scattering from an ellipsoid; the errors are empirically derived in analytical forms.