Time-Harmonic Fields in Source-Free Bianisotropic Media

A bianisotropic medium is defined as one in which the field vectors D and H depend on both E and B, but may not be parallel to either. A moving medium appears bianisotropic to the laboratory observer, even if it is isotropic in its rest frame. It is shown that, for time-harmonic fields, a bianisotropic medium can be viewed as one which is electrically and magnetically anisotropic with properly defined dyadic operators. In particular, a moving medium can be characterized by a permittivity tensor and a permeability tensor for plane-wave propagation. This characterization simplifies the solution of electromagnetic problems in moving media. As illustrated, the dispersion relations in a moving uniaxially anisotropic medium are obtained, and the problem of a plane wave normally incident upon a moving uniaxial medium is solved.