High power dielectric resonator filter

Abstract

A dielectric resonator filter has a series of cavities enclosing respective ones of a series of dielectric resonators, wherein each cavity includes a resonator support configured as a cylinder of thermally conductive, electrically insulating material such as boron nitride. The support is positioned coaxially with the resonator along a central axis of the cavity, and is located in tandem with the resonator. Physical connection of the support to the resonator is facilitated by provision of a thread along an inner surface of the support, and the provision of an outer thread on the resonator surface to be received within the thread of the support. The support is mounted to an end wall of the cavity, thereby to complete a thermally conductive path for withdrawal of heat from the resonator to the exterior of the filter. Each support is provided with windows through which tuning and/or mode coupling screws can be inserted, thereby to locate a screw behind an end surface of the resonator. The screw is supported by a sidewall of the cavity and extends radially inward of the cavity in a plane which is parallel to the resonator end surface and spaced apart from the end surface to inhibit the formation of electric discharge arcs in the case of elevated electromagnetic power. Coupling between cavities is accomplished by means of a cruciform iris.