Improved quality factor of Hetero Acoustic Layer (HAL) SAW resonator combining LiTaO3 thin plate and quartz substrate

For mobile communication, acoustic wave filters are being continuously required better steepness of a passband and a smaller temperature coefficient of frequency (TCF). Recently, various Hetero Acoustic Layer (HAL) types of surface acoustic wave (SAW) devices were reported by different groups including us [1-5]. HAL SAW devices inherently have many variations of structure and a lot of potentials. In this study, we report the bandwidth (BW) and impedance ratio (Z ratio) of different designs of HAL SAW resonators using a LiTaO
₃
thin plate on a quartz substrates.