A Three-Dimensional Finite-Difference Time-Domain Scheme Based on a Transversely Extended-Curl Operator

A three-dimensional (3d) finite-difference time-domain (FDTD) scheme is presented with improved isotropy characteristics and higher Courant number than the standard Yee scheme. The basic idea is to transversely extend the curl operator in order to improve the transverse Laplacian representation of the curl–curl operator. A stability analysis is performed, and the dispersion characteristics of the proposed scheme are investigated. It is shown that the latter is significantly more isotropic than the regular FDTD scheme. Additionally, it is proved that under certain conditions a unity Courant number can be achieved, and the resulting scheme is characterized by dispersion characteristics complementary to those of the regular FDTD scheme. Numerical simulations are performed that validate the theoretically derived results.