US 12,244,287 B2
Filter device and multiplexer
Takuya Sato, Nagaokakyo (JP); Masahiro Teramoto, Nagaokakyo (JP); and Keisuke Ogawa, Nagaokakyo (JP)
Assigned to MURATA MANUFACTURING CO., LTD., Kyoto (JP)
Filed by Murata Manufacturing Co., Ltd., Nagaokakyo (JP)
Filed on Nov. 7, 2022, as Appl. No. 17/981,600.
Application 17/981,600 is a continuation of application No. PCT/JP2021/021022, filed on Jun. 2, 2021.
Claims priority of application No. 2020-114051 (JP), filed on Jul. 1, 2020.
Prior Publication US 2023/0077950 A1, Mar. 16, 2023
Int. Cl. H03H 7/42 (2006.01); H03H 7/01 (2006.01); H03K 19/173 (2006.01)
CPC H03H 7/42 (2013.01) [H03H 7/1783 (2013.01); H03K 19/1737 (2013.01)] 16 Claims
OG exemplary drawing
 
1. A filter device comprising:
a multilayer body including a plurality of dielectric layers laminated together;
an unbalanced terminal;
a first balanced terminal and a second balanced terminal;
a first resonant circuit connected to the unbalanced terminal; and
a second resonant circuit connected to the first balanced terminal and the second balanced terminal and electromagnetically coupled with the first resonant circuit; wherein
the first resonant circuit includes a first resonator in which a first inductor and a first capacitor are connected in parallel between the unbalanced terminal and a reference potential;
the second resonant circuit includes a second resonator including a second inductor connected between the first balanced terminal and the second balanced terminal and a second capacitor and a third capacitor connected in series between the first balanced terminal and the second balanced terminal;
the plurality of dielectric layers include a first layer;
the first inductor includes a first wiring electrode provided on the first layer and a first conductor and a second conductor connected to the first wiring electrode and extending in a laminating direction of the multilayer body;
the second inductor includes a second wiring electrode on the first layer and a third conductor and a fourth conductor connected to the second wiring electrode and extending in the laminating direction of the multilayer; and
the second wiring electrode has a line length longer than a line length of the first wiring electrode.