Design and Characterization of a 2-DOF MEMS Ultrasonic Energy Harvester With Triangular Electrostatic Electrodes

This letter presents a microelectromechanical systems (MEMS) based energy harvester designed for applications such as the powering of implanted biomedical devices. The harvester is mechanically excited by an external source of ultrasonic waves with triangular electrostatic electrodes being used to produce electrical power from the vibrations of the system´s proof mass. Comparisons are made with a previous MEMS harvester that uses conventional comb-finger electrostatic electrodes to demonstrate that the triangular electrodes result in a more effective conversion process. Experimental characterization shows that the device produces an average power output of 27.6 nW, which corresponds to a 29% increase in power output over the conventional comb-finger device.