Novel interpretation of physical optics errors, fictitious penetrating rays and corrections by hybrid use of PO and AFIM

A novel interpretation of physical optics (PO) is discussed and two mechanisms are identified as error factors, that is, (1) errors in diffraction coefficients and (2) fictitious penetrating rays (Oodo, M. et al., IEICE Trans. Electron., vol.E77-C, no.6, p.995-1004, 1994). Based upon these observations, new methods, named PO-AF and PTD-AF, are proposed which eliminate the fictitious penetrating rays from PO and PTD (physical theory of diffraction), respectively. The methods are based on decomposing PO currents into two currents which are the sets of equivalent currents in the aperture field integration method (AFIM) for reflection and shadow waves. The accuracy is confirmed numerically for corner reflectors and circular arc reflectors.