JPS6441301A - Dielectric filter - Google Patents

Abstract

PURPOSE:To manufacture lots of kinds of dielectric filters with low cost and different electric characteristics by providing a slit for inserting a conductor adjusting the degree of coupling between resonators not being metallized opened to the side face of a dielectric block between through holes and inserting the coupling adjusting conductor to the slit so as to make the dielectric block simple. CONSTITUTION:A rectangular prism dielectric block 1a is provided with plural, e.g., two resonator through holes 1a-1 in parallel and in exciting an electromagnetic wave to both the resonators formed by metallizing 1a-4 both side faces in parallel with the both through holes 1a-1 and one face of the dielectric block 1a at the opening side of the through hole 1a-1 including the inner face of the through hole 1a-1, each resonator is coupled electromagnetically at a specific frequency, that is, the pass band frequency of the filter. The electromagnetic coupling quantity depends on the distance D between the resonators and the coupling area. Thus, in inserting a conductor 1b of the same potential as that of an outer metallized face into the slit 1a-3, it acts like a shield plate thereby reducing the electromagnetic coupling quantity between the resonators. That is, the electromagnetic coupling quantity between the resonators is set optionally by varying the area (length LXinsertion depth W) of the conductor 1b inserted to the slit 1a-3.