Patent ID: 6356169
Filing Date: 2002-03-12
Classification: H01P

Abstract:
A band pass filter comprising three or more resonant-line holes disposed in a dielectric block, a resonant line formed on an inner surface of each of the holes, and an outer conductor disposed on the outer surfaces of the dielectric block so that a dielectric filter is formed;wherein one end of each resonant line is a short-circuited end, and the other end thereof is an open end; the sectional area size of each of the resonant-line holes is changed at a certain point in the axial direction of the resonant-line hole; the sectional area size on the short-circuited-end side or open-end side of at least one of the plurality of resonant-line holes is made different from those of the other resonant-line holes; and regarding all the resonant-line holes symmetric with respect to a symmetry axis disposed at the center of the dielectric block in a direction in which the plurality of resonant-line holes is aligned, the sectional area sizes of said resonant-line holes at said short-circuited-end side or open-end side thereof are made the same so as to form coupling between adjacent resonant lines.