Dielectric filter having stepped resonator holes with offset hole portions

摘要

In a dielectric block, resonator holes have steps thereby providing a portion having a larger inner diameter and a portion having a smaller inner diameter, and the smaller inner diameter portion of each resonator hole is formed on the side of a short-circuited end surface. By forming the small inner diameter portions of the resonator holes relatively close to each other, the coupling between the two resonators becomes inductive coupling. By contrast, when small inner diameter portions are formed further apart from each other, the coupling between the two resonators becomes capacitive coupling. The coupling strength can be changed by adjusting the distance between the small inner diameter portions.