Title:
SURFACE ACOUSTIC WAVE FILTER DEVICE AND DUPLEXER
Document Type and Number:
WIPO Patent Application WO/2008/053651
Kind Code:
A1
Abstract:
A surface acoustic wave filter device in which sharpness of filter characteristics
can be enhanced and pass bandwidth can be enlarged. In the surface acoustic wave
filter device (1), longitudinal coupling resonator type first surface acoustic
wave filter portion (10) and second surface acoustic wave filter portion (20)
are cascaded, a signal flowing through a first signal line (6) connecting both
second IDTs (12, 22) electrically has a phase shifted by 180° from that of
a signal flowing through a second signal line (7) connecting both third IDTs (13,
23), a surface acoustic wave resonator (31) is connected between the first and
second signal lines (6, 7), and the resonance point of the surface acoustic wave
resonator (31) is arranged in an attenuation region in the vicinity of the low
band side end of pass band of the filter or the antiresonance point is arranged
in an attenuation region in the vicinity of the high band side end of pass band of
the filter.
Inventors:
TAKAMINE YUICHI (JP)
Application Number:
PCT/JP2007/068773
Publication Date:
May 08, 2008
Filing Date:
September 27, 2007
Export Citation:
Assignee:
MURATA MANUFACTURING CO (JP)
TAKAMINE YUICHI (JP)
TAKAMINE YUICHI (JP)
International Classes:
H03H9/64; H03H9/145; H03H9/72
Domestic Patent References:
| WO2006049000A1 | 2006-05-11 | |||
| WO1997000556A1 | 1997-01-03 |
Foreign References:
| JPH0865098A | 1996-03-08 | |||
| JP2002314370A | 2002-10-25 | |||
| JP2001308672A | 2001-11-02 | |||
| JPH0454011A | 1992-02-21 | |||
| JP2001308672A | 2001-11-02 |
Other References:
See also references of EP 2063530A4
Attorney, Agent or Firm:
MIYAZAKI, Chikara (5-4 Tanimachi 1-chome, Chuo-ku, Osaka-sh, Osaka 12, JP)
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