An explicit and unconditionally stable FDTD method for 3-D electromagnetic analysis

In this paper, an explicit and unconditionally stable finite-difference time-domain (FDTD) method is developed for electromagnetic analysis. It is stable for an arbitrarily large time step irrespective of space step, and accurate for a time step solely determined by accuracy. The method retains the strength of the conventional explicit FDTD in avoiding a matrix solution while eliminating the conventional FDTD's shortcoming in time step. Numerical experiments in both 2-D and 3-D simulations have demonstrated its superior performance in stability and efficiency without losing accuracy. The proposed method successfully generates stable and accurate results with a time step 10 13 times larger than that allowed by the conventional FDTD in an example where the time step required by accuracy is 10 13 times larger than that permitted by stability.