FDTD Calculation of Cavity Resonant Frequencies in Case of Nonuniform Internal Magnetic Field Distribution

An FDTD formulation which can handle mom uniform internal magnetic field distributions is used to obtain resonant frequencies for a rectangular cavity filled with magnetic material. The nonuniform internal field distribution is obtained by an iterative method. The nonuniformity of the internal field should be considered when the applied field is of the same order as saturation magnetization, or when the magnetic device is small. It is assumed that the material is initially saturated in the direction of local internal field