FDTD modeling of weakly conductive wires dispersed in a dielectric mixture

In this paper, a lumped FDTD model of weakly conductive wires is presented. The goal is to provide a simple and robust technique, which allows electromagnetic modeling of dielectric mixtures with longitudinal conductive inclusions, like carbon fibers, without the need for rigorous representation of the geometry of cylindrical wires on FDTD grid. It is shown that lumped FDTD models of thin wires available in the literature are not applicable due to large penetration depth when compared with typical diameters of carbon fibers. Computational examples confirm the validity of the model and show its advantageous applicability to the retrieval of macroscopic electromagnetic properties of composites with longitudinal conductive inclusions.