A surface acoustic wave (SAW) substrate for a duplexer, such as a Personal Communication Service handy phone system in the U.S.A., is required to have a good temperature stability, an optimum electromechanical coupling factor, and a large reflection coefficient. The conventional method of depositing a SiO 2 film on a thick Al electrode/LiTaO3 substrate to improve its temperature coefficient of frequency (TCF) is not effective for SAW resonator-type devices, because good frequency characteristics are not obtained due to large convex portions on the surface of SiO2 film. However, resonators having a large reflection coefficient, an excellent TCF, and good frequency characteristics were realized using the following two new structures: (I) SiO2 film/grooved Al electrode/LiTaO3 structure and (II) reflection of a shear horizontal (SH) wave at free edges on a SiO 2 film/thin Al electrode/LiTaO3 structure substrate.
|ジャーナル||Japanese Journal of Applied Physics, Part 1: Regular Papers and Short Notes and Review Papers|
|出版物ステータス||Published - 2006 5 25|
ASJC Scopus subject areas
- Physics and Astronomy(all)