Body Force Based Droplet Ejection by GHz Acoustic Micro-Transducer

This paper proposes a novel nozzle-free acoustic droplet ejection system based on GHz acoustic MEMS transducer. A strong body force could be generated to eject droplets when the GHz pulse signal is applied to the transducer. Compared with other acoustic ejection methods, the body force-based method generates focused radiation pressure without additional acoustic focus structures. Given its small size, nozzle-free, high acoustic radiation pressure and compatibility with complementary metal oxide semiconductor (CMOS) fabrication, the acoustic droplet ejection system has great potential in ink-jet printing, bioprinting and drug delivery applications.