RADAR POLARIMETRY APPLIED TO SCATTERING FROM IRREGULAR LAYERED MEDIA

Full-wave expressions are derived for the Mueller matrix elements that provide a complete polarimetric characterization of the electromagnet ic fields scattered from irregular layered media consisting of dielect ric coatings over dissipative substrates. The upper interface between free space and the coating material and the substrate is a two-dimensi onally random rough surface, and the bottom interface between the subs trate and the coating material is a planar surface. Each term of the f ull-wave expression for the vertically or horizontally polarized elect romagnetic fields scattered by the irregular stratified media is shown to have a clear physical interpretation. The full-wave solutions sati sfy the reciprocity and duality relationships in electromagnetic theor y and are invariant to coordinate transformations. The expressions for the scattered fields reduce to that for the specularly reflected wave when the layered structure is a parallel stratified medium. The Muell er matrix or the modified Mueller matrix are measurable quantities tha t are used to relate the scattered Stokes vector to the incident Stoke s vector. The elements of these matrices are related to commonly measu red quantities in remote sensing and in ellipsometry. The analysis is relevant to problems of communication in irregular stratified media, r emote sensing of irregular stratified media, and interpretation of ell ipsometric data obtained from layered media. (C) 1996 Optical Society of America.