A ferrite-filled cylindrical cavity

The modes in a ferrite-filled cylindrical waveguide have been analyzed, and a characteristic equation given for their propagation constants in terms of the frequency and applied magnetic field. However, there have been no reported experimental confirmations of these solutions. It is convenient to carry out the experiment by measuring the related resonances in a ferrite-filled cylindrical cavity. This has been done for the and , modes in a symmetrically excited cavity. The measured resonant frequencies are in general agreement with numerical results based on the solution of the characteristic equation and the theories of Polder and Rado. Assuming that , the components of the tensor permeability below the magnetic saturation of the ferrite may be determined over a range of frequencies from the measured curves of resonance. This type of measurement avoids certain difficulties inherent with the perturbation method. The curves of resonance may also be used to calculate the gyromagnetic ratio of the ferrite.