Tunable dielectric resonator bandpass filter

A simple but effective technique has been applied to magnetically tune the quasi-TE/sub 011/ mode dielectric resonator. The tuning was achieved by means of a ferrite rod situated centrally in the dielectric resonator and extending over the shield. The ferrite parameters were changed by DC magnetic field. The method assures the high quality factor of the resonator, over 3.4% tuning range and sufficiently good spurious response.