High-Frequency Resonator Using A1 Lamb Wave Mode in LiTaO3 Plate

Acoustic wave devices utilizing plate waves in thin lithium tantalate (LiTaO
₃
) have the potential of achieving high resonance frequency with a suitable electromechanical coupling factor and a relatively small temperature coefficient of frequency (TCF). The influence of Euler angle and plate thickness on the characteristics of plate waves has been investigated. High-frequency resonators using first antisymmetric Lamb wave mode (A
₁
) in (0°, 42°, 0°) LiTaO
₃
thin plates have been fabricated and optimized. The resonance frequency is as high as 5 GHz, with a relative bandwidth of 7.3% and an impedance ratio of 72 dB. Finally, the TCF of (0°, 42°, 0°) LiTaO
₃
has been evaluated. Therefore, it is proved that A
₁
Lamb wave mode propagating in LiTaO
₃
at a Euler angle close to (0°, 42°, 0°) is suitable for high-frequency devices.