Abstract: A compact dielectric resonator of high Qu, in which an electrode formed of an oxide superconducting material is provided on a surface of the dielectric so as to serve as an electrode. A dielectric filter, dielectric duplexer and a communications device, in which the compact resonator is incorporated, are also provided. The dielectric which constitutes the dielectric resonator of the present invention is preferably a Ba(Mg, Ma)03-based dielectric (wherein Ma is at least one pentavalent elemental metal but cannot be Ta alone), and the oxide superconducting electrode is formed of an oxide superconducting material selected from among a RE—M—Cu—O-based oxide superconducting material (wherein RE is a rare earth element and M is an alkaline earth metal element), a Bi—Sr—Ca—Cu—O-based oxide superconducting material (which encompasses those in which Bi is partially substituted by Pb), and a Tl—Ba—Ca—Cu—O-based oxide superconducting material.

Abstract: A method for producing a superconducting thick film involves the steps of forming a thick layer comprising a superconducting material on a substrate; firing the thick layer formed on the substrate; subjecting the fired thick layer to cold isostatic pressing; and refiring the thick layer subjected to cold isostatic pressing.