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Patent Searching and Data


Title:
FILTER CIRCUIT, FILTER CIRCUIT ELEMENT, AND MULTIPLEXER/DEMULTIPLEXER
Document Type and Number:
WIPO Patent Application WO/2019/107081
Kind Code:
A1
Abstract:
According to the present invention, a low-pass filter (12) is provided with: a first inductor (L1); a second inductor (L2) magnetically coupled to the first inductor (L1); a third inductor (L3); and a first capacitor (C1). The first inductor (L1) is connected between a first port (P1) and an intermediate point (Pm) that is a connection point to which the second inductor (L2) is connected between the first inductor (L1) and a second port (P2). The second inductor (L2) is connected between the intermediate point (Pm) and a ground terminal (GND). The third inductor (L3) is connected between the intermediate point (Pm) and the second port (P2), and a first parallel resonant circuit PR1 is configured from the third inductor (L3) and the first capacitor (C1). The first inductor (L1) and the second inductor (L2) are coupled in a relationship such that a negative impedance (-M) is generated between the intermediate point (Pm) and the third inductor (L3) due to the magnetic field coupling between the first and second inductors.

Inventors:
ISHIZUKA Kenichi (10-1, Higashikotari 1-chome, Nagaokakyo-sh, Kyoto 55, 〒6178555, JP)
Application Number:
JP2018/041039
Publication Date:
June 06, 2019
Filing Date:
November 05, 2018
Export Citation:
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Assignee:
MURATA MANUFACTURING CO., LTD. (10-1, Higashikotari 1-chome Nagaokakyo-sh, Kyoto 55, 〒6178555, JP)
International Classes:
H03H7/09; H03H7/075; H03H7/46; H04B1/52
Domestic Patent References:
WO2016125515A12016-08-11
WO2017159282A12017-09-21
Foreign References:
JP2014027690A2014-02-06
Attorney, Agent or Firm:
KAEDE PATENT ATTORNEYS' OFFICE (1-4-34, Noninbashi Chuo-ku, Osaka-sh, Osaka 11, 〒5400011, JP)
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