Patent ID: 9419579
Filing Date: 2016-08-16
CPC Classification: H03H

Claim Text:
1. A band pass filter circuit comprising: an input terminal; an output terminal; a signal line connecting the input terminal and the output terminal to each other; and a plurality of main LC parallel resonators each including an inductor and a capacitor; wherein the plurality of main LC parallel resonators are configured to be electromagnetically coupled with one another in a predetermined manner; the plurality of main LC parallel resonators include a first-stage main LC parallel resonator and a second-stage main LC parallel resonator; first ends of the first-stage main LC parallel resonator and the second-stage main LC parallel resonator of the plurality of main LC parallel resonators are connected to the signal line and second ends of the first-stage main LC parallel resonator and the second-stage main LC parallel resonator of the plurality of main LC parallel resonators are connected to one another; at least one sub LC parallel resonator, including an inductor and a capacitor, which defines an attenuation pole is provided between a ground and the connected second ends of the first-stage main LC parallel resonator and the second-stage main LC parallel resonator of the plurality of main LC parallel resonators; and the at least one sub LC parallel resonator is directly connected to both the second end of the first-stage main LC parallel resonator and the second end of the second-stage main LC parallel resonator.