Microwave resonator

A microwave resonator comprising:

• a hollow tube comprising a plurality of electrically conductive wall faces which together define a tube wall, the tube wall defining a tube bore, the tube extending along a length axis from a first end to a second end;
• the tube wall having an N fold rotational symmetry about the length axis where 2<N<10;
• a first electrically conductive covering plate covering the first end of the tube;
• a second electrically conductive covering plate covering the second end of the tube;
• a plurality of dielectric pucks, each of the pucks comprising first and second end faces and a side wall extending therebetween, each of the pucks being dimensioned such that when in the tube bore its dominant resonant mode is a doubly degenerate mode;
• the plurality of pucks being arranged within the tube bore spaced apart from each other and the covering plates, each of the pucks being arranged with its end faces normal to the length axis and centered on the length axis, the puck adjacent to the first covering plate being an input puck;
• each of the pucks being spaced apart from the tube wall by a plurality N of electrically conductive spacer blocks, the spacer blocks being spaced equally around the length axis;
• each of the pucks being separated from an adjacent puck of the plurality of pucks in the tube bore by a coupling gap, each coupling gap having an electrically conductive iris plate arranged therein, each of the iris plates having at least one coupling slot extending therethrough;
• the spacer blocks being spaced apart from the covering and iris plates;
• each of the pucks having a symmetry breaking structure associated therewith, each of the symmetry breaking structures being adapted to modify the coupling between the two degenerate modes of its associated puck and also their relative frequencies.