An accurate FDTD algorithm for dispersive media using a piecewise constant recursive convolution technique

The recursive convolution (RC) approach is one of several that have been developed to extend the basic finite difference time domain (FDTD) algorithm to permit modeling of broadband pulse propagation in frequency-dependent dielectric and magnetic media. This paper has shown that a second order accurate scheme can be obtained with the recursive convolution approach without abandoning the assumption of piecewise constant fields over each time step. This new formulation yields an algorithm with the same memory requirements and computational speed as the original RC method of Luebbers et al. (1990). Comparisons with the dispersion errors of piecewise linear recursive convolution and the auxiliary equation methods of Young et al. (1995) and Joseph et al. (1991) show the formulation in this paper to be at least as accurate as these other methods.