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

• Published in: IEEE transactions on magnetics Vol. 43; no. 4; pp. 1517 - 1520
• Main Authors: Farahani, A.V., Konrad, A.
• Format: Journal Article Conference Proceeding
• Language: English
• Published: New York, NY IEEE 01-04-2007; Institute of Electrical and Electronics Engineers; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Cavity resonant frequencies; Cross-disciplinary physics: materials science; rheology; Deviation; Exact sciences and technology; Finite difference methods; finite difference time-domain (FDTD) methods; Holes; Magnetic anisotropy; Magnetic devices; Magnetic fields; Magnetic materials; magnetic microwave devices; Magnetic moments; Magnetism; Materials science; Mathematical analysis; micro magnetics; Nonuniform; Nonuniformity; Other topics in materials science; Perpendicular magnetic anisotropy; Physics; Resonant frequencies; Resonant frequency; Saturation (magnetic); Saturation magnetization; Time domain analysis; finite difference time-domain (FDTD) methods; Microwave radiation; Magnetic field effects; Calculus; micromagnetics; Time domain method; Magnetic devices; Microwave devices; Cavity resonant frequencies; Magnetic fields; Finite difference method; Magnetic properties; magnetic microwave devices
• ISSN: 0018-9464; 1941-0069
• DOI: 10.1109/TMAG.2007.891461

An improved finite difference time-domain formulation that can work with nonuniform internal magnetic field distributions is introduced and used to obtain the resonant frequencies of a rectangular cavity filled with magnetic material. The nonuniformity of the internal field should be considered when the applied field is of the same order as the saturation magnetization. Even in case of large applied fields, when the magnetic device is small, the deviation from uniform distribution is significant. The nonuniform internal field distribution is obtained by an iterative method, assuming that the magnetic medium is saturated in the direction of local internal field (the condition for equilibrium distribution of magnetization). It is shown that this solution is stable and satisfies the standard boundary value problem of electromagnetism