A new approach to the generalized optical cross-section theorem in electromagnetics

This work is concerned with electromagnetic scattering in general nonhomogeneous, lossy, anisotropic media. A new approach to the generalized optical cross-section theorem (for two incident fields) and of its particular manifestation, the ordinary optical theorem (for a single incident field), is developed that is relevant to electromagnetic direct and inverse problems. The derived results are based on cross-flux concepts and Green's function theory, and apply in arbitrary background media (where the scatterers are embedded), under arbitrary incident fields, and in arbitrary representational domains (plane wave, multipole field, Green's function, and so on).