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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 10382006 B1

PDFFull Text
Date of Patent:
Aug. 13, 2019

Filed:

Sep. 28, 2018

Variable frequency filter, radio frequency front-end circuit, and communication terminal

Applicant:

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

Inventors:

Hideki Tsukamoto, Kyoto, JP;

Masakazu Tani, Kyoto, JP;

Kei Matsutani, Kyoto, JP;

Assignee:

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

Attorney:

Pearne & Gordon LLP

Primary Examiner:

Nhan T Le

Int. Cl.
CPC ...
H04B 1/38 (2015.01); H03H 7/46 (2006.01); H03H 7/075 (2006.01); H03F 3/19 (2006.01); H03H 7/24 (2006.01); H03H 7/38 (2006.01); H03H 9/54 (2006.01); H04B 1/04 (2006.01); H04B 1/10 (2006.01); H03H 9/56 (2006.01); H03H 9/60 (2006.01); H03H 9/64 (2006.01);
U.S. Cl.
CPC ...
H03H 7/465 (2013.01); H03F 3/19 (2013.01); H03H 7/075 (2013.01); H03H 7/24 (2013.01); H03H 7/38 (2013.01); H03H 7/461 (2013.01); H03H 9/54 (2013.01); H03H 9/542 (2013.01); H03H 9/568 (2013.01); H03H 9/605 (2013.01); H03H 9/6436 (2013.01); H03H 9/6483 (2013.01); H04B 1/0475 (2013.01); H04B 1/1018 (2013.01); H03F 2200/451 (2013.01); H03H 2210/012 (2013.01); H03H 2210/036 (2013.01);
Abstract

A first attenuation circuit is connected between a node and ground, and the node is located between a ladder resonance circuit and a transmitter-side terminal. A second attenuation circuit is connected between a first parallel arm resonator of the ladder resonance circuit and ground and is connected in series to the first parallel arm resonator. The first attenuation circuit includes a second parallel arm resonator and a first switch that switches between a first state in which the second parallel arm resonator is connected to the node and a second state in which the first switch is open. The second attenuation circuit includes a capacitor and a second switch that switches between a first state in which the capacitor is connected to the first parallel arm resonator and a second state in which the first parallel arm resonator is connected to ground.

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