A langasite crystal has been paid to much attention as a substrate for surface acoustic wave (SAW) devices recently, because it has a larger electromechanical coupling factor (ks) than a quartz and an excellent temperature coefficient of frequency (TCF) similar to the quartz. A leaky SAW (LSAW) and a leaky pseudo SAW (LPSAW) of the various rotated Y cut langasite substrates grown by Czockralski method were measured by an ultrasonic microscope. The measured results were compared with the theoretical values calculated by five kinds of material constants. The TCFs of Rayleigh SAW filters having various Al thickness of interdigital transducer (IDT) on various rotated Y plates were measured. It was clarified that (0°, 142°, 24.5°) and (0°, 143°, 24°) substrates showed turnover temperatures of 25 °C and 30 °C, and more excellent TCFs (1.83 and 1.63 ppm/°C) at normalized Al-IDT thickness 0.0125 compared with ones reported until now. Measured results of electromechanical coupling factor on their substrates showed almost equal values to theoretical ones.
|Number of pages||4|
|Journal||Proceedings of the IEEE Ultrasonics Symposium|
|Publication status||Published - 1998 Dec 1|
|Event||Proceedings of the 1998 International Ultrasonics Symposium - Sendai, Miyagi, Jpn|
Duration: 1998 Oct 5 → 1998 Oct 8
ASJC Scopus subject areas
- Acoustics and Ultrasonics