Numerical algorithms for the FDiTD and FDFD simulation of slowly varying electromagnetic fields

The simulation of slowly varying electromagnetic fields is possible for ver y large, realistic problems with finite-difference implicit time-domain (FD iTD) and frequency-domain (FDFD) formulations on the basis of the consisten t Finite-Integration Technique (FIT). Magneto-quasistatic time-domain formu lations combined with implicit time marching schemes require the repeated s olution of real-valued symmetric systems. The solution of driven frequency domain problems usually consists in the solution of one non-Hermitean syste m. Preconditioned conjugate gradient-type methods are well-suited for this task. They allow the efficient solution even for consistent singular or nea r-singular systems, which typically arise from formulations for slowly vary ing electromagnetic fields using the Maxwell-Grid-Equations of the FI-Metho d. Numerical results for TEAM workshop 11 benchmark problem and for a large practical problem, a shading ring sensor, show that the presented algorith ms are capable of solving realistic problems for large numbers of unknowns in acceptable calculation times on contemporary medium sized workstations. Copyright (C) 1999 John Wiley & Sons, Ltd.