Space-time reversal symmetry properties of electromagnetic Green's tensors for complex and bianisotropic media

Abstract

Space-Time reversal symmetry properties of free-Space electromagnetic Green's tensors for complex and bianisotropic homogeneous media are discussed. These properties are defined by symmetry of the medium under consideration, of the point sources and of the vector S connecting the source and the point of observation. The constraints imposed on Green's tensors by the restricted Time reversal, by the center and anticenter of symmetry are independent on the vector S orientation. Other Space-Time reversal operators lead to constraints on Green's tensors only for some special directions in Space. These directions are along the (anti)axes and (anti)planes and normal to the (anti)axes and (anti)planes. The full system of the continuous magnetic point groups for description of Space-Time reversal symmetry of Green's tensors is defined and a general group-theoretical method for calculation of simplified forms of Green's tensors is presented.