Generalized image method for radiation problems involving the Minkowskian isotropic medium

We formulate a generalized image theory for the radiation of electromagnetic sources in the vicinity of the interface between vacuum and a Minkowskian isotropic medium (MIM). The MIM is a special kind of a Tellegen medium where the isotropy is an invariant, i.e, the 4D constitutive relation of a MIM is invariant for any inertial observer. We demonstrate that because of this property the fields reflected/transmitted by a vacuum-MIM interface can be expressed in terms of suitable virtual (image) sources. This analytical result is an extension of the image theory for some known special cases: the perfect electromagnetic conductor (PEMC), the perfect electric conductor (PEC) and the perfect magnetic conductor (PMC).