Title :
SAW reflection characteristics and NSPUDT orientations on langasite
Author :
Takeuchi, M. ; Tanaka, M. ; Imanishi, Y.
Author_Institution :
Dept. of Electron. Eng., Tamagawa Univ., Tokyo, Japan
Abstract :
Langasite (LGS, La3Ga5SiO14) single crystal is an attractive substrate for SAW devices requiring good temperature stability and high electromechanical coupling constant K2. However, the SAW reflection characteristics due to a strip electrode on LGS have not been reported so far. It is necessary for designing the SAW devices such as SPUDT based filters and resonators with grating reflector. Recently several research groups have shown theoretically and experimentally that the (0°,140°,22°~24°) cut on LGS is a very promising cut. This cut is characterized by zero TCD, moderately high K2, and zero power flow angle. In this paper, we describe the analytical results of SAW reflection characteristics using coupled-mode and perturbation theories. From the analysis of reflection characteristics, we found that (0°,140°,22°~24°) cut is the excellent natural single phase unidirectional transducer (NSPUDT) orientations with large directivity as well as zero TCD, high K2, and zero power flow angle
Keywords :
gallium compounds; lanthanum compounds; perturbation theory; surface acoustic wave resonator filters; surface acoustic wave transducers; La3Ga5SiO14; NSPUDT orientations; SAW reflection; coupled-mode theory; electromechanical coupling constant; filters; grating reflector; langasite; natural single phase unidirectional transducer; perturbation theory; resonators; single crystal; strip electrode; temperature stability; zero power flow angle; Electrodes; High K dielectric materials; High-K gate dielectrics; Load flow; Reflection; Stability; Strips; Surface acoustic wave devices; Surface acoustic waves; Temperature;
Conference_Titel :
Ultrasonics Symposium, 1998. Proceedings., 1998 IEEE
Conference_Location :
Sendai
Print_ISBN :
0-7803-4095-7
DOI :
10.1109/ULTSYM.1998.762149
