Magnetodynamical modes in a spherical ferrite cavity

The axial-symmetrical modes of a spherical cavity containing magnetised-ferrite material are calculated. It can be shown that the different modes of the resonator are coupled by the gyrotropic medium. The field of the gyrotropic resonator is represented by an infinite sum of the eigenfunctions of the spherical resonator containing an isotropic medium. Under consideration of the boundary conditions the dependence of the resonance frequency on the magnetic-bias field may be obtained.