A Theory of Scattering by Sinusoidal Metal Surfaces.
Abstract
A rigorous theory of plane wave scattering by periodic metal surfaces is presented. The physical optics approximation is used to determine the current distribution on the metal surface to first order, but this approximate distribution is modified by multiplication with a Fourier series, whose fundamental period is that of the surface profile (Floquet's theorem). The coefficients of the Fourier series are determined by invoking the condition that the field radiated by the current distribution into the lower (shielded) half-space cancels the primary plane wave in this space range. The scatter problem is thereby reduced to the familiar task of solving a system of linear equations. For certain basic types of surface profiles, the coefficients of the linear system are obtained in closed form (Bessel functions for the sinusoidal profiles considered here, and exponential functions for piecewise linear profiles). Thus, the method requires no numerical integral evaluation and, consequently, is computationally efficient. Since the boundary condition of zero tangential electric field at the metal surface is not utilized, the field within the grooves of the periodic scatter need not be known--a definite advantage of the new method. In addition to a summary of the theory, numerical results for TE-, TM-, and circular polarization of the incident plane wave are presented. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- May 01, 1977
- Accession Number
- ADA040002
Entities
People
- F. Schwering
- G. Whitman
Organizations
- United States Army Communications-Electronics Command