GB1468310A - Microwave cavity resonators - Google Patents

Abstract

1468310 Resonators and filters MICROWAVE ASSOCIATES Inc 18 Feb 1975 [8 April 1974] 6892/75 Heading H1W A tubular cavity resonator is excited to resonate in the circular-electric TE 01n mode and is provided with one or more axially-oriented conductive pins for supression of other modes, notably TM modes. Fig. 5 shows a filter made from a coupler series of such resonators. A typical resonator 53 is provided with up to four pins 84 or 84<SP>1</SP> arranged symmetrically about the cavity axis on one or both end walls of the cavity at a radial position where they couple most strongly with the axial electric field of the unwanted TM mode. The resonator may also be provided with pins (not shown) extending radially from the cylindrical wall at a position intermediate the end walls. Such pins couple with a radial electric component of the TM mode. The cavities are arranged alternatively on either side of a plate 41, forming a common end wall, which is provided with inter-cavity coupling apertures 43-46 and input/output coupling apertures 42, 47. The coupling apertures are tuned by adjustable radial screws 42<SP>1</SP>-47<SP>1</SP>. The cavities are tuned by screws 89-93 located in the centres of the end walls 71-75. The specification also describes a single-cavity filter (Fig. 1, not shown), and a double-cavity filter (Fig. 2, not shown). In the latter the cavities are endcoupled to input/output waveguides, and are end-coupled to each other. Tuning of the cavities is effected by a radial screw located in the cylindrical wall intermediate the end walls.