US 12,308,813 B2
Filter circuit and multilayered filter device
Shuhei Sawaguchi, Tokyo (JP); Masahiro Tatematsu, Tokyo (JP); Yuta Ashida, Tokyo (JP); Tetsuzo Goto, Tokyo (JP); Yoshinori Matsumaru, Tokyo (JP); Shigemitsu Tomaki, Tokyo (JP); and Longfei Yi, Tokyo (JP)
Assigned to TDK CORPORATION, Tokyo (JP)
Filed by TDK CORPORATION, Tokyo (JP)
Filed on Jan. 30, 2023, as Appl. No. 18/161,286.
Claims priority of application No. 2022-015577 (JP), filed on Feb. 3, 2022.
Prior Publication US 2023/0246621 A1, Aug. 3, 2023
Int. Cl. H03H 7/01 (2006.01); H01F 27/28 (2006.01); H01F 27/29 (2006.01); H01F 27/40 (2006.01); H01G 4/01 (2006.01); H01G 4/30 (2006.01)
CPC H03H 7/0115 (2013.01) [H01F 27/2804 (2013.01); H01F 27/29 (2013.01); H01F 27/40 (2013.01); H01G 4/01 (2013.01); H01G 4/30 (2013.01); H03H 7/0161 (2013.01); H01F 2027/2809 (2013.01)] 20 Claims
OG exemplary drawing
 
1. A filter circuit comprising:
a pair of balanced input ports;
a pair of balanced output ports;
a first resonator and a second resonator provided in parallel between the pair of balanced input ports and the pair of balanced output ports in a circuit configuration, the first resonator and the second resonator being magnetically coupled to each other; and
a third resonator provided in parallel to the first resonator, between the pair of balanced input ports and the first resonator in the circuit configuration,
wherein
between the first resonator and the second resonator, a capacitor is present but no inductor is present in the circuit configuration.