Ferrite-Tuned Resonant Cavities

The case of a dominant-mode rectangular cavity with a slab of ferrite against one side wall is treated. Use is made of the change in effective rf permeability of the ferrite in response to changes in the applied static magnetic field. Experimental results on an X-band cavity show a 10 per cent tuning range with an unloaded Q of 1,000 or more at 9,000 megacycles. Calculation of the Q of the cavity from the loss tangents of the ferrite material is outlined.