Rigorous coupled-wave approach to scattering from cylindrical and spherical inhomogeneous objects

Abstract

Rigorous coupled wave analysis (RCWA) approach is employed to determine electromagnetic (EM) scattering from cylindrical (circular and noncircular) spatially, inhomogeneous, anisotropic material objects. From the late 70's to the present, the RCWA approach has become an extremely important technique for the study of EM diffraction from one and two dimensional planar gratings. RCWA which is a spectral domain technique, is based on expanding Maxwell's equations in a set of Floquet harmonics, and from this expansion, arranging the unknowns of the system in a state variable (SV) form from which a solution may be found. For the study of diffraction from planar gratings, the technique has proved to be a very fast, accurate, and effective method which requires only the solution of relatively small matrix and eigenvalue equations. When the RCWA approach is applied to study scattering from two and three dimensional objects, the theta and phi azimuthal coordinates represent periodic coordinates from which Floquet harmonics may be used to expand the unknowns of the system. Secs. 1 and 2 will review the RCWA method and its application to E-mode planar diffraction gratings. Sec. 3 will present the basic RCWA EM formulation to study scattering from inhomogeneous, anisotopic circular, cylindrical objects, and Sec. 4 will briefly review the RCWA EM formulation used to study scattering from elliptical inhomogeneous objects.