Generating and Focusing the Ultrasound Waves Using Elastomer-based Capacitive Micro-Speakers

Ultrasound wave is a kind of waves with the frequency higher than the human audible frequency. Although ultrasound was first used for military identification purposes, it has been used for decades for various other applications, especially medical applications. Medical applications of ultrasound include diagnostic and therapeutic applications, such as for the treatment of cancer. In this paper, for the first time, electrostatically-actuated micro-speakers made of a dielectric elastomer (DE) have been used to generate and focus the ultrasonic waves using Micro-Electro-Mechanical Systems (MEMS) technology. The results have shown that a single micro-speaker could not generate an efficient focused wave, so an array of the micro-speakers has been considered. The layout of the micro-speakers is a square array of Bessel Panel. It has been shown that by adopting a suitable excitation frequency as well as number of the elements in the Bessel’s panel, the DE-based capacitive micro-structures can focus the generated sound wave in a pre-determined area.