Duality transformations, Green dyadics and plane-wave solutions for a class of bianisotropic media

Duality transformations are defined as linear transformations between pairs of vector fields and sources. A class of bianisotropic media is defined so that a pair of duality transformations can be found which leave the media invariant (self dual). It is seen that for such media the permittivity, permeability and nonreciprocity parameters must be multiples of the same dyadic while the chirality parameter may be an arbitrary dyadic. Any source and field in such a medium can be decomposed in a pair of self-dual components which see the bianisotropic medium as two equivalent anisotropic media of affine-isotropic type. The Green dyadics in these two media can be solved through affine transformations and the Green dyadics of the original bianisotropic medium can be written in explicit analytic form. The plane-wave dispersion equation can be solved through a similar self-dual decomposition of fields.