Incremental Diffraction Coefficients for Planar Surfaces. Part 1. Theory
Abstract
Exact expressions for incremental diffraction coefficients at arbitrary angles of incidence and scattering are derived directly in terms of the corresponding two-dimensional, cylindrical diffraction coefficients. Specifically, if one can supply an expression for the conventional diffraction coefficients of a two-dimensional planar scatterer, one can immediately find the incremental diffraction coefficients of a two-dimensional planar scatterer, one can immediately find the incremental diffraction coefficients through direct substitution. No integration, differentiation, or specific knowledge of the current is required. The derivation is limited to perfectly conducting scatters that consist of planar surfaces, such as the wedge, the slit in an infinite plane, the strip, parallel or skewed planes, polygonal cylinders, or any combination thereof; and requires a known expression (whether exact or approximate) for the two-dimensional diffraction coefficients produced by the current on each different plane. Special attention is given to defining unambiguously all real angles and their analytic continuation into the imaginary values required by the incremental diffraction coefficients. The physical theory of diffraction, geometrical theory of diffraction, and physical optics incremental diffraction coefficients agree in the case of the infinite wedge. The two dimensional diffraction coefficients are recovered when the general expressions for the incremental diffraction coefficients are integrated over an infinite straight line. The general method is used to obtain, for the first time, the incremental diffraction coefficients for the infinitely long, narrow strip and slit.
Document Details
- Document Type
- Technical Report
- Publication Date
- Apr 01, 1987
- Accession Number
- ADA208595
Entities
People
- Arthur Yaghjian
- Robert A. Shore
Organizations
- Rome Laboratory