Propulsion Measurement of High Frequency Underwater SAW Actuators

Underwater self-propelled robots have been studied in various fields such as life sciences, microbiology and medical. Among them, self-propelled robot with SAW (Surface Acoustic Wave) has attracted much attention, because of the simple surface electrode structure. SAW transducer can be miniaturized with the higher resonance frequency. We investigated the possibilities about higher driving frequency SAW actuators; only 10MHz was tested in the past. Although the formula of acoustic radiation pressure predicts that the higher frequency SAW transducer can generate the larger propulsion, the specific experimental data is scarce. In this paper, we measured the propulsion and the speed of the SAW actuators at 10, 20 and 30 MHz driving frequencies.