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The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.

The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.

Patent No.:

US 10644673 B1

PDFFull Text
Date of Patent:
May. 05, 2020

Filed:

Aug. 07, 2018

Radio frequency filter circuit, duplexer, radio frequency front end circuit, and communication apparatus

Applicant:

Murata Manufacturing Co., Ltd., Kyoto, JP;

Inventors:

Koji Nosaka, Kyoto, JP;

Takaya Wada, Kyoto, JP;

Assignee:

MURATA MANUFACTURING CO., LTD., Kyoto, JP;

Attorney:

Pearne & Gordon LLP

Primary Examiner:

Benny T Lee

Assistant Examiner:

Hafizur Rahman

Int. Cl.
CPC ...
H03H 9/64 (2006.01); H04B 1/48 (2006.01); H04B 1/00 (2006.01); H04B 1/40 (2015.01); H03H 9/56 (2006.01); H03H 9/60 (2006.01); H03H 9/70 (2006.01); H03H 9/05 (2006.01); H03H 9/72 (2006.01); H03H 9/54 (2006.01);
U.S. Cl.
CPC ...
H03H 9/6483 (2013.01); H03H 9/0542 (2013.01); H03H 9/542 (2013.01); H03H 9/568 (2013.01); H03H 9/605 (2013.01); H03H 9/6403 (2013.01); H03H 9/6406 (2013.01); H03H 9/706 (2013.01); H03H 9/72 (2013.01); H03H 9/725 (2013.01); H04B 1/00 (2013.01); H04B 1/006 (2013.01); H04B 1/40 (2013.01); H04B 1/48 (2013.01);
Abstract

A radio frequency filter circuit (A) includes a series-arm resonator (), a parallel-arm resonator (), a parallel-arm resonator () that is connected between a node xand a ground terminal, a switch (SW) that is arranged between the node xand the ground terminal and switches between electrical connection and electrical non-connection of a path connecting the node x, the parallel-arm resonator (), and the ground terminal. The parallel-arm resonator () and a series circuit in which the parallel-arm resonator () and the switch (SW) are connected in series are connected in parallel between the node xand the ground terminal. A resonant frequency (frp) of the parallel-arm resonator () is lower than a resonant frequency (frs) of the series-arm resonator (). A resonant frequency (frp) of the parallel-arm resonator () is higher than the resonant frequency (frp) of the parallel-arm resonator ().

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