Title:
ACOUSTIC WAVE FILTER DEVICE
Document Type and Number:
WIPO Patent Application WO/2018/003338
Kind Code:
A1
Abstract:
Provided is an acoustic wave filter device with which the steepness of the filter characteristic is improved and loss within the passband is reduced, while suppressing transverse mode ripple. This acoustic wave filter device comprises a ladder-type filter having series-arm resonators S1-S4 and parallel-arm resonators P1-P4 that comprise elastic wave resonators. In at least one series-arm resonator S1 wherein the acoustic velocity in first and second edge regions A1 and A2 is made lower than the acoustic velocity in a center region A0, first electrode fingers 19 have a wide portion 19a the width of which in the second edge region A2 is greater than the remaining portions, and second electrode fingers 20 have a wide portion 20a the width of which in the first edge region A1 is greater than the remaining portions. For at least one of the remaining series-arm resonators S2-S4 and the parallel-arm resonators P1-P4, the first and second electrode fingers 19 and 20 have wide portions the width of which in both the first edge region A1 and the second edge region A2 is greater than the remaining portions.
Inventors:
OKADA SHINICHI (JP)
Application Number:
PCT/JP2017/018703
Publication Date:
January 04, 2018
Filing Date:
May 18, 2017
Export Citation:
Assignee:
MURATA MANUFACTURING CO (JP)
International Classes:
H03H9/145; H03H9/64
Domestic Patent References:
| WO2015198897A1 | 2015-12-30 |
Foreign References:
| JP2013518455A | 2013-05-20 | |||
| JP2012186808A | 2012-09-27 | |||
| JP2000183681A | 2000-06-30 |
Attorney, Agent or Firm:
MIYAZAKI & METSUGI (JP)
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