Dielectric filter having inductive coupling windows between resonators, and transceiver using the dielectric filter

Abstract

A dielectric filter includes a first dielectric block having a through bore, substantially all of the surface area of the first dielectric block being covered with a conductive film to define a first dielectric resonator whose magnetic energy varies in the direction of an axis of the through bore. A first coupling window is formed in the conductive film on a first side surface for coupling an input signal applied thereto to the first dielectric resonator. A second coupling window is formed on a second side surface in a location wherein the magnetic energy in the first dielectric block is relatively high so that magnetic energy exits the first dielectric block via the second coupling window. A second dielectric block has a through bore and substantially all of the surface area of the second dielectric block is covered with a conductive film to define a second dielectric resonator. A third coupling window is formed on a first side surface of the second dielectric block at a location corresponding to the second coupling window such that magnetic energy leaving the first dielectric block via the second coupling window enters the second dielectric block via the third coupling window and sets up a magnetic field in the second dielectric block whose magnetic energy varies in the direction of the through bore of the second dielectric block. A fourth coupling window is formed on a second surface of the second dielectric block at a location where the resonant magnetic energy in the second dielectric block is relatively high such that magnetic energy leaves the second dielectric block via the fourth coupling window.