Chapter 3 Electromagnetic fields in linear bianisotropic mediums

Abstract

An isotropic medium has electromagnetic properties, which are the same in all directions. However, the notion of isotropy, as encountered in elementary treatments of electromagnetics, is an abstraction, which requires qualification when applied to real materials. Electromagnetically isotropic mediums are characterized simply by scalar constitutive parameters which relate the induction field phasors D and H to the primitive field phasors E and B . Often, naturally occurring materials and artificially constructed mediums are more accurately described as anisotropic rather than isotropic. Anisotropic mediums exhibit directionally dependent electromagnetic properties, such that D and E are not aligned or H and B are not aligned. Dyadics (second-rank Cartesian tensors) are needed to relate the primitive and the induction field phasors in anisotropic mediums. Bianisotropy is the natural generalization of anisotropy. A broad overview of electromagnetic bianisotropy is provided in this chapter. The survey includes anisotropic mediums as an important subcategory of bianisotropic mediums. A discussion is presented on the constitutive relations for bianisotropic mediums, and their general properties and commonly encountered classifications of bianisotropic mediums are presented. The propagation of plane waves in bianisotropic mediums is considered and the Green-function method is widely used in source-field problems. Representations of dyadic Green functions for bianisotropic mediums and the conceptualization of bianisotropic mediums as homogenized composite mediums are also discussed.