Analysis and Fabrication of Layered Surface-Acoustic-Wave Filter (Ⅲ)
Date Issued
2004-07-31
Date
2004-07-31
Author(s)
DOI
922212E002001
Abstract
With the development of communication
technology, there has been a growing
interest in the study of SAW filters based on
layered structures. By including a high
velocity layer between a piezoelectric layer
and a substrate, the surface wave velocity
can be increased significantly. This results in
an increase of the SAW frequency without
decreasing the electrode spacing into the
sub-micron region. This three-year project is
to study the analysis and fabrication of
layered SAW filters by both the theoretical
and experimental approaches. In the first
phase, an IF SAW filter was designed and
fabricated. The coupling-of-modes (COM)
mode was established to calculate its
frequency response. Besides, we adopted the
inversion algorithm to determine the
practical COM parameters. In the second
phase, dispersion relation and frequency
response of a layered SAW device were
analyzed and discussed based on effective
permittivity. In addition, a method for
measuring the properties of thin film in the
sub-micron range has been developed based
on the SAW sensor responses. Finally, a
ZnO/sapphire layered SAW was fabricated
and tested. The frequency responses of
ZnO/sapphire SAW filters were calculated
by adapting modified COM model. These
calculated results provide useful guidelines
for the design of a layered SAW device. The
fruitful results of this project will contribute
to not only a further study on the layered
SAW resonator, but the development of
SAW devices applied in RFID and
biosensing system.
Subjects
layered SAW filter
effective
permittivity
permittivity
COM mode
film property
inversion
inversion
Publisher
臺北市：國立臺灣大學應用力學研究所
Type
report
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