Design of reflectionless media for transient electromagnetic waves

A method for modelling reflectionless conductive dispersive media is presented. The media are either half-spaces or finite dispersive slabs with a spatially varying impedance. The problem of finding reflectionless media for plane waves at normal incidence is formulated as an inverse problem where the constitutive relation is to be determined as a function of depth given a reflection kernel which is zero. The inverse problem is solved by a time-domain Green function technique. It is seen that non-reflecting half-spaces can be constructed in a number of different ways, whereas non-reflecting slabs can only be found if the back-wall is non-conducting.