Green dyadic for a class of nonreciprocal bianisotropic media

The possibility of finding nn analytic Green dyadic expression for a class of bianisotropic media, defined by the relations <(epsilon)over bar> = <(tau mu)over bar>(T), <(xi)over bar> = x x (I) over bar + xi uu, and <(zeta)over bar> = z x (I) over bar + xi uu between the medium parame ter dyadics, is studied. It is shown that the determinant of the dyadic Helmholtz operator, an operator of fourth order, can be expressed as a product of two second-order operators. A method for finding the solution for the Green dyadic in the form of infinite series in terms of powers of the dimensionless parameter xi xi/ mu(0)epsilon(0) is given. For small values of the parameter, a two-term approximation is seen to take a simple analytic form. As an Appendix, another approach through the Fourier transformation is briefly discussed. Dyadic formalism is applied throughout in the analysis. (C) 1998 John Wiley & Sons, Inc.