Dielectric filter having at least one stepped resonator hole with an elongated cross-section

摘要

A dielectric filter and a dielectric duplexer having a dielectric block with resonator holes formed therein, each having a large- sectional- area portion and a small-sectional-area portion so that the resonator hole has different respective inner diameters at an open- circuited end and a short-circuited end. Each large-sectional-area portion is formed with the cross-sectional shape of an elongated circle, an ellipse, or a rectangle, for example, the cross-sectional shape defining a longitudinal axis which is disposed at an angle against with respect to a plane in which the resonator holes are arranged. The invention increases the degree of freedom in providing a desired resonant frequency and a desired degree of coupling between resonators, in order to be able to easily provide desired filter characteristics, even in a case in which the external dimensions of the required dielectric block are restricted. Also disclosed is a method of manufacturing the dielectric filter and dielectric duplexer, as well as a radio transceiver utilizing the dielectric duplexer.