Recently, several applications have required radio frequency filters with a narrow bandwidth and high attenuations. A ZnO film/quartz structure has a good potential to such a requirement. In this paper, we show the optimization of the ZnO/quartz structure to obtain a nearly zero temperature coefficient of frequency (TCF) while maximizing the electro-mechanical coupling coefficient (k2). In the previous papers published by one of the authors about the ZnO/quartz structure, a nearly zero TCF with a small electro-mechanical coupling coefficient, or non-zero TCF with maximized k2 was reported. However, both zero TCF and maximized k2 have not yet been simultaneously obtained. In this study, we investigated the optimized structure by calculation and also confirmed it by measurement.
ASJC Scopus subject areas
- Physics and Astronomy(all)