Patent ID: 7468643
Filing Date: 2008-12-23
Classification: H01P

Abstract:
1. A bandpass filter comprising an input terminal electrode, an output terminal electrode, and a plurality of resonators formed in a multilayer dielectric substrate comprising dielectric layers stacked one upon another, wherein the plurality of resonators each comprises a conductor pattern whose length in a signal propagation direction is basically λ/4 when the propagation wavelength at a generally center frequency of a passband is represented by λ, one ends of the plurality of resonators are each grounded as grounded ends, the grounded ends being arranged on the same side of the multiplayer dielectric substrate and juxtaposed in sequence, and the plurality of resonators comprise six resonators from a first resonator to a sixth resonator, the resonators being arranged such that an ungrounded end of the first resonator is connected to the input terminal electrode through capacitance or inductance, an ungrounded end of the sixth resonator is connected to the output terminal electrode through capacitance or inductance, adjacent resonators of the second to fifth resonators are electromagnetically coupled with each other, and ungrounded ends of the first resonator and the second resonator, ungrounded ends of the first resonator and the third resonator, ungrounded ends of the sixth resonator and the fourth resonator, ungrounded ends of the sixth resonator and the fifth resonator are coupled with each other by being connected together through capacitances.