Reducing dissipation in piezoelectric flexural microplate resonators in liquid environments

While piezoelectric microplates are emerging as a promising MEMS liquid-based sensing platform, often acoustic radiation losses limit device performance. This paper presents a new analysis of microplate acoustic radiation losses through the use of traditional analytical models for the fundamental mode and a new finite element model that is used to analyze trends affecting Q for both the fundamental and higher order flexural modes. Results from these models are compared with experimental measurements of frequency and Q measured using both electrical characterization and the laser Doppler vibrometer for multiple modes of the microplate in water as compared to air and vacuum. Finally, a microplate mode with a high initial Q of around 150 in air and that demonstrates an increase in Q going from air to water is presented as a strong candidate for use in droplet based sensing applications.