Taiyo Yuden Co., Ltd.

Jaeho Jeong

Makoto Inoue

Hideyuki Sekine

Naoto Kobayashi

Masato Ito

Naoyuki Tasaka

Sachiko Tanaka

Shuei Hashimoto

A filter includes an input terminal, an output terminal, a ground terminal, a first capacitor and a second capacitor that are connected in series between the input terminal and the output terminal, a capacitive element that is connected in parallel to the first capacitor and the second capacitor between the input terminal and the output terminal, and has a Q factor that is smaller than a Q factor of the first capacitor and is smaller than a Q factor of the second capacitor, and an inductor that has a first end and a second end, the first end being coupled to a node that is provided between the first capacitor and the second capacitor and that is coupled to the capacitive element through the first capacitor and the second capacitor, the second end being coupled to the ground terminal.

Filter and multiplexer

A filter includes an input terminal, an output terminal, a first ground terminal, a second ground terminal, a first inductor having a first end coupled to a first node in a path between the input terminal and the output terminal and a second end coupled to a second node, a second inductor having a first end coupled to the second node and a second end coupled to the first ground terminal, and a third inductor having a first end coupled to the second node and a second end coupled to the second ground terminal.

A multiplexer includes: a first bandpass filter having a first end coupled to a common terminal and a second end coupled to a first terminal, the first bandpass filter having a first passband; a second bandpass filter having a first end coupled to the common terminal and a second end coupled to a second terminal, the second bandpass filter having a second passband that does not overlap with the first passband and is higher than the first passband; and a first band-stop filter having a first end coupled to the first terminal and a second end coupled to the second terminal, the first band-stop filter having a first stopband formed of a first attenuation pole and a second attenuation pole, the first attenuation pole being located within the first passband or near the first passband, the second attenuation pole being located within the second passband or near the second passband.

Multiplexer

A filter includes: a substrate; input and output terminals located on the substrate; a resonant circuit located in a series pathway between the input and output terminals; a first component including a first inductor, which is electrically connected between a first node in the series pathway and a ground, and mounted in a first region on the substrate; a second component including a second inductor, which is electrically connected between a second node different from the first node in the series pathway and a ground, and mounted in a second region different from the first region on the substrate; and a third component including an acoustic wave resonator, which is electrically connected between a third node between the first and second nodes in the series pathway and a ground, and mounted in a third region between the first and second regions on the substrate.

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Tokyo, Japan

Jaeho Jeong