Duality in Electromagnetics: Application to Tellegen Media

This article discusses the generalized duality transformation in electromagnetics. The duality transformation affects material parameters in the bi-anisotropic constitutive relations. It will be shown that the two magnetoelectric phenomena, chirality and nonrecipro city, behave differently in the duality transformation. The analysis of the duality transformation is shown to be relevant to the question about the existence of non-reciprocal Tellegen media.