Acoustic Loss of GHz Higher-Order Lamb Waves in Thin-Film Lithium Niobate: A Comparative Study

• Published in: Journal of microelectromechanical systems Vol. 30; no. 6; pp. 876 - 884
• Main Authors: Lu, Ruochen, Yang, Yansong, Gong, Songbin
• Format: Journal Article
• Language: English
• Published: New York IEEE 01.12.2021; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Acoustic attenuation; acoustic delay line; Acoustic delay lines; Acoustic waves; Acoustics; Comparative studies; Damping; Delay lines; Delays; Dispersion; Electrodes; Lamb mode; Lamb waves; lithium niobate; Lithium niobates; Q-factor; quality factor; Resonators; Room temperature; thin-film devices; Transducers; Wave attenuation; Wave propagation
• ISSN: 1057-7157; 1941-0158
• DOI: 10.1109/JMEMS.2021.3114627

This work reports a comparative study of acoustic loss between different Lamb waves at GHz in thin-film lithium niobate (LiNbO 3 ). The propagation loss (PL) of higher-order Lamb waves in thin-film LiNbO 3 is studied for the first time using acoustic delay line (ADL) testbeds. The acoustic wave attenuation and quality factors (<inline-formula> <tex-math notation="LaTeX">Q </tex-math></inline-formula>) of different Lamb waves are extracted, showing higher <inline-formula> <tex-math notation="LaTeX">Q\text{s} </tex-math></inline-formula> for higher-order Lamb modes than fundamental modes in air and vacuum at room temperature. The extracted <inline-formula> <tex-math notation="LaTeX">Q\text{s} </tex-math></inline-formula> are higher than those reported in thin-film LiNbO 3 resonators, implying the electrode and anchor-induced loss as the dominant loss factors. The ADL-based loss analysis framework is readily extendable to acoustic damping study in other microwave acoustic platforms. [2021-0165]