A 3-DoF MEMS ultrasonic energy harvester

The harvesting of electrical energy from vibrational motion to power electronic devices remains a major focus of microelectromechanical systems (MEMS) research. Conversion mechanisms such as piezoelectric, electromagnetic or electrostatic transducers have been used for this purpose. Most MEMS energy harvesters to date use ambient vibrations as their source of kinetic energy. In contrast, this paper presents the design and characterization of a 3-degree of freedom MEMS energy harvester that utilizes electrostatic transducers to convert ultrasonic waves into electrical energy. The device´s ability to harvest energy is demonstrated via the charging of a storage capacitor, with experimental results showing that the device is able to harvest 12.6nW of average electrical power.