• physical optics approximation;
  • diffraction;
  • line integral representation;
  • field equivalent principle


An alternative approach for analyzing diffraction field for physical optics (PO) is presented in this paper. This approach separates geometrical optics field and diffraction field from the total field analytically by using field equivalence principle or the divergence theorem and choosing the special surfaces which lie on the reflection and shadow boundaries, and then transfers the surface integral which represents the diffraction field into simple line integral analytically. Two types of representations of PO field lead to the two types of line integral expressions for PO diffraction field. One is very simple and is not reported in the literature to the best knowledge of the authors, and another is identical with available result, which can be considered as alternative derivation of the available result. The proposed approach differs from other high frequency analysis in that it's not asymptotic evaluation of radiation integration, or heuristic or empirical. The superiority of this new analysis is demonstrated numerically. © 2002 Wiley Periodicals, Inc. Microwave Opt Technol Lett 35: 206–211, 2002; Published online in Wiley InterScience ( DOI 10.1002/mop.10559