Reduction of numerical dispersion in FDTD method through artificial anisotropy

In this paper, a simple and computationally low-cost modification of the st andard finite-difference time-domain (FDTD) algorithm is presented to reduc e numerical dispersion in the algorithm. Both two- and three-dimensional ca ses are considered, It is shown that the maximum error in phase velocity ca n be reduced by a factor of 2-7, depending on the shape of the FDTD cell. A lthough the reduction procedure is optimal for only single frequency, numer ical examples show that the proposed method can also improve the accuracy s ignificantly in wide-band inhomogeneous problems.