Patent ID: 8847709

Claim:
A resonator filter comprising: a conductive housing having a bottom, walls, and a lid, a space of which housing is divided into resonator cavities by conductive partition walls, and in each of the conductive partition walls separating two successive ones of the resonator cavities on a transmission path there is a coupling opening (CPO) to excite an oscillation in a latter one of the two successive resonator cavities, wherein the CPO has side walls and in which CPO there is a movable tuning element having an adjusting range within which to adjust the strength of coupling between the successive resonator cavities and thus the bandwidth of the resonator filter and each tuning element includes a conductive part and is grounded with a grounding coupling to that conductive partition wall within which it is located, wherein the tuning element in the CPO is supported to that partition wall on opposite sides of the side walls of the CPO each of the tuning elements is fastened to a control rod, which extends above the lid of the conductive housing of the resonator filter and which control rod is mechanically connected to an electrically controllable actuator to move the tuning element in its adjusting range, and each of the turning elements includes a dielectric layer between the conductive part of the tuning element and a conductive part of that conductive partition wall within which the tuning element is located.