Generalized reflection coefficient for non uniform transmission lines

In this paper we present the formula for the generalized reflection coeffic ient that relates the upgoing wave to the downgoing wave at the interface b etween an isotropic homogeneous half-space and an isotropic inhomogeneous d ielectric slab. Various forms of epsilon(z) that admit closed-form solution s for the generalized reflection coefficient when the inhomogeneous planar profile is analytic and continuos are also derived.