An Explicit and Unconditionally Stable FDTD Method for the Analysis of General 3-D Lossy Problems

The root cause of the instability of an explicit finite difference time-domain (FDTD) method is quantitatively identified for the analysis of general lossy problems where both dielectrics and conductors can be lossy and inhomogeneous. Based on the root cause analysis, an efficient algorithm is developed to eradicate the root cause of instability, and subsequently achieve unconditional stability in an explicit FDTD-based simulation of general lossy problems. Numerical experiments have demonstrated the unconditional stability, accuracy, and efficiency of the proposed method.