Swimmer with submerged SiO2/Al/LiNbO3 surface acoustic wave propulsion system

Acoustic propulsion system presents a novel underwater propulsion approach in small scale swimmer. This study introduces a submerged surface acoustic wave (SAW) propulsion system based on the SiO₂/Al/LiNbO ₃ structure. At 19.25 MHz, the SAW propulsion system is proposed and investigated by the propulsion force calculation, PIV measurements and propulsion measurements. 3.3 mN propulsion force is measured at 27.6 V${}_{pp}$. To evaluate the miniature swimmer, the SAW propulsion systems with multiple frequencies are studied. At 2.2 W, the submerged SAW propulsion system at 38.45 MHz demonstrates 0.83 mN/mm${}^2$ propulsion characteristics. At 96.13 MHz and 24 V${}_{pp}$, the movements of miniature swimmer with a fully submerged SAW propulsion system are recorded and analyzed to a maximum of 177 mm/s. Because of miniaturization, high power density, and simple structure, the SAW propulsion system can be expected for some microrobot applications, such as underwater drone, pipeline robot and intravascular robot.