Complex Envelope Weaker HIE With Higher Order PML Algorithm for FDTD Simulation

Weaker hybrid implicit–explicit (WHIE) algorithm with complex envelope (CE) method is proposed for structures with fine details along a single direction in bandpass problems. Higher order perfectly matched layer (PML) formulation is proposed for absorption improvement in open regions. By introducing alternating-direction implicit (ADI) discretized form and adding proper disturbance terms, it can obtain relaxed stability condition under the same Courant–Friedrichs–Levy (CFL) numbers (CFLNs) compared with the other implicit algorithms resulting in the improvement of efficiency. Furthermore, time step can also be enlarged according to the bandpass lowpass-sampling theorem which improves the efficiency in bandpass circumstances.