| 摘要 |
PURPOSE:To simplify the constitution of a coaxial filter by covering the areas near the open ends of inner and outer circumferential surfaces, and the end surface at the short- circuit side of a dielectric material of a coaxial structure with a metallic conductor to obtain a coaxial resonator having stepped variations for the characteristic impedance of lines and arraying plural units of such resonators. CONSTITUTION:The areas near the inner and outer circumferential surfaces and the end surfaces at the short-circuit side of coaxial resonators 51-53 using coaxial dielectric materials are covered with a metallic conductor, and an inner conductor 49 of an open part is fixed with the solder containing silver. The short-circuited parts and open parts of the resonators 51-53 are fixed to a housing 10 and a holding plate 50 respectively with the solder containing silver. A tuning screw 48 is set at the position of the housing corresponding to the conductor 49, and the tuning frequency is varied with control of the screw 48. Furthermore input/output coupling circuits 25 and 26 are set close to the short-circuit surfaces of resonators 51 and 53 to ensure a connection between the input and the output. An inductive connection is given between stages through a metallic coductor at the short-circuit side and an uncovered dielectric material part. Thus, the deterioration of both no-load Q and vibration resistance of a coaxial filter is prevented and the structure of the filter is simplified. |
