Plane Waves in Decomposable Bi-Anisotropic Media

Abstract

The class of decomposable bi-anisotropic media was recently defined to consist of media in which any electromagnetic field can be decomposed in two individual electromagnetic fields satisfying certain conditions for the electromagnetic fields. Also it was shown that, for a medium in this class, the fourth-order Helmholtz determinant operator governing the basic electromagnetic fields can be factorized, i.e., expressed as a product of two second-order operators. In the present paper, plane-wave propagation in the general decomposable medium is studied. Analytical solutions are derived for the dispersion equation and the polarizations of the eigenwaves are also determined in analytic form. As a check the expressions are applied to a medium with previously known solutions. In an appendix, conditions for the medium dyadics of the decomposable bi-anisotropic medium are derived for the case when the medium is lossless.