EM wave excitation and propagation in a generally anisotropic homogeneous medium: a coordinate-free approach

A simple coordinate-free approach for the derivation of spectral Green´s functions is presented referring to a generally anisotropic homogeneous medium with spatial dispersion. On this basis, an elegant method to determine the plane-wave modes and the associated modes by properly specifying the excitation is proposed. These results are applicable, e.g., to bianisotropic and diffusive media, as well as the mean field problems in random media. For anisotropic magnetodielectric media, asympotic expressions for the radiation field of finite sources are obtained highlighting the excitation of an associated mode along an optic axis. The absorbing boundary conditions on a spherical surface and their approximate version for an arbitrary convex surface are developed.