A three-dimensional angle-optimized finite-difference time-domain algorithm

We present a three-dimensional finite-difference time-domain (FDTD) algorithm to minimize the numerical dispersion error at preassigned angles. Filtering schemes are used to further optimize its frequency response for broad-band simulations. A stability analysis of the resulting FDTD algorithm is also provided. Numerical results show that the dispersion error around any preassigned angle can be reduced significantly in a broad range of frequencies with small computational overhead.