Pass band width adjustment manner null of bandpass filter and bandpass

摘要

PROBLEM TO BE SOLVED: To reduce deterioration of narrow band-pass characteristics at a low cost and to facilitate adjustment by forming a high-temperature superconductor film on a surface facing the internal wall surface of a metal housing, where a dielectric substrate having a microstrip line resonator is installed. ;SOLUTION: This dielectric substrate 2, where microstrip resonators each composed of a ground conductor 3 and a strip conductor 4 of the high-temperature superconductor film are formed, is arranged in a normal conductor metal housing 1 so that the ground conductor surface 3 is grounded to the internal wall of the metal housing 1. A housing upper lid is grounded to the bottom surface of the dielectric substrate 5 in terms of high frequency, by electrically connecting the high-temperature conductor film 6 to the metal housing 1 at its periphery. Thus, the top surface internal wall of the housing 1 facing a ground conductor part is covered with the high conductor film 6, so that a region of the internal wall of the housing 1 where the normal conductor occupies is only sidewall; and then deterioration of narrow band-pass characteristics is reduced, and height of the side wall of the housing is varied, to vary the coupling coefficient between the resonators, thereby facilitating the adjustment the passing band width.;COPYRIGHT: (C)2001,JPO