Patent ID: 6608537
Filing Date: 2003-08-19
Classification: H01P

Abstract:
A band-pass filter comprising:a dielectric body; a metal film provided on an outside surface of the dielectric body or inside of the dielectric body; a ground electrode provided on the surface of the dielectric body or inside of the dielectric body, and opposed to the metal film via at least a portion of the layers of the dielectric body; a pair of input-output coupling circuits coupled to first and second portions of an outer peripheral edge of the metal film, wherein each input-output coupling circuit has a coupling point; the shape and size of the metal film and the positions of the coupling points of the input-output coupling circuits being selected such that a first resonance mode being propagated in a direction that is substantially parallel to an imaginary straight line passing through the coupling points of the input-output coupling circuits, and a second resonance mode being propagated in a direction that is substantially perpendicular direction to the imaginary straight line, are generated; and the metal film having a length in the direction of the first resonance mode different from a length in the direction of the second resonance mode and having a protruding portion or a concavity provided thereon in a position where the resonance electric field in at least one of the resonance modes is strong and the input-output coupling circuits are positioned such that the first and second resonance modes are coupled to each other.