Patent ID: 8471650
Filing Date: 2013-06-25
Classification: H01P

Abstract:
1. A diplexer, comprising: a multilayer body having a stack of a plurality of dielectric layers on top of each other; a first ground electrode that is disposed on a lower face of the multilayer body; a plurality of strip-like first resonant electrodes that are arranged side by side on a first interlayer of the multilayer body for mutual electromagnetic-field coupling, with their one ends connected to a ground potential so as to serve as a quarter-wavelength resonator; a plurality of strip-like second resonant electrodes that are arranged side by side on a second interlayer of the multilayer body different from the first interlayer for mutual electromagnetic-field coupling, with their one ends connected to a ground potential so as to serve as a quarter-wavelength resonator that resonates at a frequency higher than a frequency at which the first resonant electrode resonates; a strip-like input coupling electrode that is disposed on a third interlayer of the multilayer body located between the first interlayer and the second interlayer, faces an input-stage first resonant electrode of the plurality of first resonant electrodes, over more than half of an entire longitudinal area thereof for electromagnetic-field coupling, faces an input-stage second resonant electrode of the plurality of second resonant electrodes, over more than half of an entire longitudinal area thereof for electromagnetic-field coupling, and has an electric signal input point for receiving input of an electric signal from an external circuit; a strip-like first output coupling electrode that is disposed on an interlayer of the multilayer body different from the first interlayer, faces an output-stage first resonant electrode of the plurality of first resonant electrodes, over more than half of an entire longitudinal area thereof for electromagnetic-field coupling, and has a first electric signal output point for producing output of an electric signal toward the external circuit; and a strip-like second output coupling electrode that is disposed on an interlayer of the multilayer body different from the second interlayer, faces an output-stage second resonant electrode of the plurality of second resonant electrodes, over more than half of an entire longitudinal area thereof, and has a second electric signal output point for producing output of an electric signal toward the external circuit, the one end of the input-stage first resonant electrode and the one end of the input-stage second resonant electrode being located on a same side, the first output coupling electrode and the second output coupling electrode in a plan view being located on opposite sides with the input coupling electrode interposed therebetween, the electric signal input point being located, on the input coupling electrode, closer to another end of the input-stage first resonant electrode than a center of a part facing the input-stage first resonant electrode, and closer to another end of the input-stage second resonant electrode than a center of a part facing the input-stage second resonant electrode, the first electric signal output point being located, on the first output coupling electrode, closer to another end of the output-stage first resonant electrode than a center of a part facing the output-stage first resonant electrode, and the second electric signal output point being located, on the second output coupling electrode, closer to another end of the output-stage second resonant electrode than a center of a part facing the output-stage second resonant electrode.