Title:
LADDER-TYPE FILTER AND DUPLEXER
Document Type and Number:
WIPO Patent Application WO/2016/174938
Kind Code:
A1
Abstract:
The objective of the present invention is to provide a ladder-type filter and a duplexer with which it is possible to improve out-of-band attenuation, achieve satisfactory impedance matching, and reduce insertion losses.
This ladder-type filter 1 is a ladder-type filter in which a passband is configured using series-arm resonators S1 to S4 and first and second parallel-arm resonators P1, P2 and P3, wherein the ladder-type filter is provided with: the series-arm resonators S1 to S4; the first and second parallel-arm resonators P1, P2 and P3; and a third parallel-arm resonator P4 which is connected in parallel with the first parallel-arm resonator P1, has a lower capacitance than that of the first parallel-arm resonator P1, and the antiresonant frequency of which is positioned outside the passband of the ladder-type filter 1. The antiresonant frequency of the first parallel-arm resonator P1 is positioned in a frequency range that is higher than the antiresonant frequencies of the second parallel-arm resonators P2 and P3.
Inventors:
TAKATA TOSHIAKI (JP)
Application Number:
PCT/JP2016/057414
Publication Date:
November 03, 2016
Filing Date:
March 09, 2016
Export Citation:
Assignee:
MURATA MANUFACTURING CO (JP)
International Classes:
H03H9/54; H03H9/64; H03H9/70; H03H9/72
Domestic Patent References:
| WO2013080461A1 | 2013-06-06 | |||
| WO2016031391A1 | 2016-03-03 |
Foreign References:
| JP2005045475A | 2005-02-17 |
Attorney, Agent or Firm:
MIYAZAKI & METSUGI (JP)
Patent business corporation Miyazaki and table-of-contents patent firm (JP)
Patent business corporation Miyazaki and table-of-contents patent firm (JP)
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