An FDTD Model of a Thin Dispersive Layer

This paper presents a new model of a finite-difference time-domain (FDTD) cell containing a thin dispersive layer. The model, derived on the basis of an equivalent-circuit approach, is applicable to both normal and tangential electric/magnetic field components. It is shown that such an inhomogeneous FDTD cell can be unequivocally transformed to the homogeneous one, provided that the thin layer is made of single-pole dispersive material. In the case of multi-pole dispersion, field components normal to the layer require approximate treatment, which can be performed with good accuracy if the poles are distant in the frequency domain. The advantage of the proposed method is in the lack of additional computational effort required to solve the scenario containing inhomogeneous electric and/or magnetic dispersive FDTD cells, when compared with their homogeneous counterparts. The solution is successfully validated against both analytical and numerical examples.