DIELECTRIC FILTER AND DIELECTRIC DUPLEXER

PURPOSE:To provide a comb-line type dielectric filter and a dielectric duplexer which show the satisfactory attenuation characteristics without using any ground metallic parts, can decrease the number of parts and manpower for production, are adaptive for reduction of sizes, can easily deal with the surface mounting problems and also shows the narrow band characteristics. CONSTITUTION:The resonator holes 12a and 12b are provided on a dielectric block 10 in its lengthwise direction, and one of both end parts of each resonator hole is used as an open side with the other end part used as a short-circuit side respectively. Furthermore both open and short-circuit sides are set on the same surface of the block 10, that is, a comb-line type. The block 10 has no coupler hole and is entirely covered with a conductive film excluding the end edges of open sides of both holes 12a and 12b. The input/output terminal holes 20a and 20b are provided at the positions near the resonator holes positioned at both ends of the open sides. Then an independent conductive film having no conduction to the conductive film formed on the outer surface part is formed over the entire length of each inner surface of both holes 20a and 20b. Thus a metallic terminal 22 is inserted through an opening part formed at the open side.