US 12,451,855 B2
Filter device and radio-frequency front-end circuit including the same
Ryouta Nobe, Nagaokakyo (JP)
Assigned to MURATA MANUFACTURING CO., LTD., Kyoto (JP)
Filed by Murata Manufacturing Co., Ltd., Nagaokakyo (JP)
Filed on Jan. 26, 2023, as Appl. No. 18/101,710.
Application 18/101,710 is a continuation of application No. PCT/JP2021/034149, filed on Sep. 16, 2021.
Claims priority of application No. 2020-161614 (JP), filed on Sep. 28, 2020.
Prior Publication US 2023/0170870 A1, Jun. 1, 2023
Int. Cl. H03H 7/01 (2006.01); H01F 27/28 (2006.01); H01F 27/29 (2006.01); H01G 4/012 (2006.01); H01G 4/30 (2006.01)
CPC H03H 7/0115 (2013.01) [H01F 27/2804 (2013.01); H01F 27/29 (2013.01); H01G 4/012 (2013.01); H01G 4/30 (2013.01); H03H 7/0161 (2013.01); H01F 2027/2809 (2013.01)] 18 Claims
OG exemplary drawing
 
1. A filter device comprising:
a multilayer body in which multiple dielectric layers are stacked in stacking direction;
a ground terminal; and
a first LC parallel resonator, a second LC parallel resonator, and a third LC parallel resonator located in the multilayer body and magnetically coupled to each other; wherein
each of the first LC parallel resonator, the second LC parallel resonator, and the third LC parallel resonator is connected to the ground terminal;
the first LC parallel resonator includes a first conductor, the second LC parallel resonator includes a second conductor, and the third LC parallel resonator includes a third conductor;
the filter device further comprises:
a connection conductor on a layer different from a layer on which the second conductor is located;
a first via including one end connected to the first conductor and another end connected to the connection conductor; and
a second via including one end connected to the third conductor and another end connected to the connection conductor; and
the connection conductor includes a first region that overlaps a portion of the second conductor in plan view of the multilayer body seen in the stacking direction such that the connection conductor is capacitively coupled to the second conductor.