Bandpass filter, and wireless communication module and wireless communication device using the bandpass filter

A bandpass filter comprising:

• a laminated body formed by stacking a plurality of dielectric layers;
• a ground electrode disposed on at least one of an upper surface and a lower surface of the laminated body;
• first to third resonance electrodes having a strip shape and sequentially arranged side-by-side, as viewed in the stacking direction, on the same interlayer or different interlayers of the laminated body such that the first to third resonance electrodes are electromagnetically coupled to each other, the first to third resonance electrodes being grounded at one end and constituting first to third resonators, respectively;
• a first input/output coupling electrode having a strip shape and disposed in an interlayer of the laminated body, the interlayer being different from the interlayer where the first resonance electrode is disposed, such that the first input/output coupling electrode faces the first resonance electrode and is electromagnetically coupled thereto;
• a second input/output coupling electrode having a strip shape and disposed in an interlayer of the laminated body, the interlayer being different from the interlayer where the second resonance electrode is disposed, such that the second input/output coupling electrode faces the second resonance electrode and is electromagnetically coupled thereto;
• and
• a resonator coupling electrode disposed in an interlayer of the laminated body, the interlayer being different from both the interlayer where the first resonance electrode is disposed and the interlayer where the third resonance electrode is disposed, and configured to provide electromagnetic coupling between the first resonance electrode and the third resonance electrode,
• wherein the first and second resonators have the same resonance frequency which is different from a resonance frequency of the third resonator;
• and
• the first to third resonators are used to produce a passband.