Z-transform theory and FDTD stability

In this paper we analyze the stability and the accuracy of finite-difference time-domain (FDTD) algorithms using Z-transform technique. Conventional time-staggered approximation of the time-derivative is replaced by a rational transfer function discrete-time filter. Then a generalized formulation of the FDTD time-stepping is presented. Finally, we show that it is possible significantly reduce the time-sampling error of FDTD algorithm by properly choosing the transfer function coefficients.