Title:
FILTER DEVICE
Document Type and Number:
WIPO Patent Application WO/2020/137263
Kind Code:
A1
Abstract:
The present invention provides a filter device with excellent filter characteristics that, without causing degradation of the filter characteristics of one bandpass type filter connected in common, can suppress the effect of a response due to a Rayleigh wave with respect to a pass band of another bandpass type filter. This filter device 10 comprises: a common connection terminal 3; a first bandpass type filter 1 that is connected to the common connection terminal 3, and that has an inductor L; and a second bandpass type filter 2 that is connected to the common connection terminal 3, and that is positioned at a lower side of the pass band than the first bandpass type filter 1. The filter device 10 uses SH waves. The first bandpass type filter 1 is a ladder type filter. Serial arm resonators S1 to S4 and parallel arm resonators P1 to P4 each have an IDT electrode. The inductor L is serially connected to the parallel arm resonator P1 having the smallest electrode finger pitch of the IDT electrode among the parallel arm resonators P1 to P4 of the first bandpass type filter 1.
Inventors:
OSADA JUNJI (JP)
NAKAHASHI NORIHIKO (JP)
NAKAHASHI NORIHIKO (JP)
Application Number:
PCT/JP2019/045254
Publication Date:
July 02, 2020
Filing Date:
November 19, 2019
Export Citation:
Assignee:
MURATA MANUFACTURING CO (JP)
International Classes:
H03H9/145; H03H9/25; H03H9/64; H03H9/72
Domestic Patent References:
| WO2017038679A1 | 2017-03-09 | |||
| WO2018139598A1 | 2018-08-02 |
Foreign References:
| JP2008160562A | 2008-07-10 | |||
| JP2015092782A | 2015-05-14 | |||
| JP2015073331A | 2015-04-16 |
Attorney, Agent or Firm:
MIYAZAKI & METSUGI (JP)
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