1988 Fiscal Year Final Research Report Summary
The Rosonators and the Resonator-Filter Utilizing Love Type Pseudo SAW
| Project/Area Number |
62460131
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| Research Category |
Grant-in-Aid for General Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Research Field |
電子機器工学
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| Research Institution | TOHOKU UNIVERSITY |
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Principal Investigator |
SHIMIZU Hiroshi Engrg Touhoku Univ. Prof., 工学部, 教授 (00005175)
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| Co-Investigator(Kenkyū-buntansha) |
SUZUKI Yuji Engrg Yamanashi Univ. Lecturer, 工学部, 講師 (70179266)
NAKAMURA Kiyoshi Engrg Touhoku Univ. Prof, 工学部, 教授 (00005365)
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| Project Period (FY) |
1987 – 1988
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| Keywords | Surface Acoustic Wave / Pseudo Surface Acoustic Wave / Love Type Surface Acoustic Wave / Surface Acoustic Wave Resonator / Love Type SAW Resonator / IDT Type Resonator / エネルギー閉じ込め型弾性表面波共振子 |
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| Research Abstract |
High electromechanical-coupling coefficient SAW substrates are required to realize high-performance SAW devices of small size. Though the pseudo SAW on Y-cut LiNbO_3 has a large electromechanical-coupling factor,its large propagation loss is unfavorable for practical applications. The pseudo SAW can be converted to the Love type SAW with: no propagation loss by depositing a metal-strip grating on the substrates. The purpose of this research project is to reveal the condition of the conversion and to develop high-performance miniaturized SAW devices by utilizing the high-coupling property. The results of this project can be summarized as follows:
1. In the case of using Au strips. (1)The propagation loss becomes neglective by the conversion of the pseudo SAW to the Love type SAW when the metal-strip thickness normalized to a wavelength is more than 1%. (2)The reflectivity per one strip is proportional to the thickness of the metal-strip. It is 0.3 provided the normalized thickness is 0.02. (3)The spurious response caused by Rayliegh wave can be suppressed by changing the rotation angle of the substrates. (4)The achieved resonator capacitance ratio is as low as 3.
2. Compared with Au strips,Ag strips has 0.7 times smaller effects to the conversion and to the reflectivety at the same thickness.
3. The dispersion curves of the Love type SAW propagating under the metal-strips can be analyzed as a function of the metal-strip thickness and the rotation angle of the substrates.
4. The frequency-temperature coefficient ofthe Love type SAW on YX-LiNbO_3 is measured. It is within -110ppm/゜C 20ppm/゜C provided the normalized metal-strip thickness is from 1.3% to 3%.
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Research Products
(4 results)
