Dielectric filter having an attenuation pole tunable to a predetermined frequency.

摘要

A dielectric filter has a plurality of dielectric resonators (24-1, 24-2, 24-3). A plurality of center conductors (23-1, 23-2, 23-3) are formed in a homogeneous monolithic block of dielectric material (20) substantially in parallel with each other, constituting the dielectric resonators (24-1, 24-2, 24-3). A plurality of electrodes for adjustment (25-1, 25-2, 25-3) are arranged on one side of the dielectric block (20), and each extends across one end of respective one of the center conductors (23-1, 23-2, 23-3). Either the distance between nearby dielectric resonators (24-1, 24-2, 24-3) or the configuration of the electrodes for adjustment (25-1, 25-2, 25-3) is changed to cause overcoupling on the basis of coupling inductance or coupling capacitance, thereby tuning an attenuation pole of the dielectric filter to a finite frequency. This allows the attenuation pole to be tuned to any desired frequency.