IMPROVED APPROXIMATION FOR EFFECTIVE PERMEABILITY IN MICROWAVE FERRITES

The nonlinear eigenvalue problem of microwave ferrite phase shift and control components is in general a function of three frequency-depende nt variables. Below ferrimagnetic resonance a reasonably accurate appr oximation has been used to reduce the number of frequency-dependent va riables to two, thereby simplifying the eigenvalue problem. Above reso nance, accurate solutions are only achievable via a computationally ex pensive iterative solution of the nonlinear eigenvalue problem. To avo id this, a new approximation is proposed, and supporting modal frequen cy calculations presented for two axisymmetric configurations suggest that the effective permeability can be computed to within 6% accuracy.