Title:
LADDER FILTER
Document Type and Number:
WIPO Patent Application WO/2014/103953
Kind Code:
A1
Abstract:
An objective of the present invention is to achieve miniaturization of a ladder filter which comprises series arm resonators comprising IDT electrodes whereupon overlap width weighting is carried out. Provided is a ladder filter (1), comprising series arm resonators (S1, S2) and parallel arm resonators (P1, P2), wherein at least one of the series arm resonators (S1, S2) comprises IDT electrodes (11) whereupon overlap width weighting is carried out and does not comprise a reflector, and wherein an acoustic wave excitation area = number of IDT electrode pairs [pair] * overlap width [λ] * (1-X/2) is 2000λ or less, where X is an apodization ratio in which X=(a-b)/a and λ is the wavelength of a propagating acoustic wave, a being the maximum overlap width in the IDT electrodes (11), and b being the aperture length in the IDT electrodes.
Inventors:
SAJI MARI (JP)
Application Number:
PCT/JP2013/084315
Publication Date:
July 03, 2014
Filing Date:
December 20, 2013
Export Citation:
Assignee:
MURATA MANUFACTURING CO (JP)
International Classes:
H03H9/64; H03H9/145
Domestic Patent References:
| WO2005011117A1 | 2005-02-03 | |||
| WO2011161987A1 | 2011-12-29 | |||
| WO2007138840A1 | 2007-12-06 | |||
| WO2011105316A1 | 2011-09-01 | |||
| WO2011115014A1 | 2011-09-22 | |||
| WO2008078573A1 | 2008-07-03 |
Foreign References:
| JPH09121136A | 1997-05-06 | |||
| JPH09246913A | 1997-09-19 | |||
| JP2001298348A | 2001-10-26 | |||
| JP2006013576A | 2006-01-12 |
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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