Inhomogeneous dielectric media: Wave propagation and dielectric permittivity reconstruction

In this paper we study the propagation of electromagnetic waves in a wavegu ide completely filled with a inhomogeneous dielectric material. The materia l is inhomogeneous in the longitudinal direction, i.e., the dielectric perm ittivity is described by a function epsilon = epsilon (0)epsilon (r),(z). W e first solve the direct problem; then we develop a computational procedure for solving the inverse problem and apply the procedure to the estimation of an unknown dielectric permittivity profile. An important feature of our approach is the expansion of the unknown epsilon (r)(z) into a power series . The dielectric permittivity profile estimation consists in determining th e unknown coefficients through error function minimization. We test our met hod by numerical experiments utilizing a genetic algorithm and obtain very accurate results.