Dielectric filter, a dielectric duplexer, and a communication apparatus

摘要

A dielectric filter comprising a dielectric block having a substantially rectangular solid shape and having an outer-conductor; a plurality of inner-conductor-coated holes disposed inside the dielectric block; the end portion of at least one inner-conductor-coated hole being an open-circuited surface on which the outer-conductor is not disposed, and an input-output electrode being capacitance-coupled to the vicinity of the end portion of that inner-conductor-coated hole; and both end portions of another inner-conductor-coated hole, which is not capacitance-coupled to an input-output electrode, are covered by the outer-conductor, and an inner-conductorless portion is provided inside the hole. Preferably an end portion of the other hole either is sunken below or protrudes above the open-circuited surface.