Rolling Rod Electrostatic Microgenerator

The difficulty of maximizing the proof mass, and lack of broadband operation, are key issues for miniaturized energy-harvesting devices. Here, a novel electrostatic energy harvester is presented, employing an external free-rolling proof mass to address these issues. A description of the operating principle is given, and the kinetic dynamics of the cylinder are analyzed. The electrostatics of the system are simulated, identifying the device performance for different dielectric dimensions and surface specifications. The fabrication of a prototype device is presented, and physical characterization results demonstrate a successful fabrication technique for dielectric sizes down to 100 nm. Capacitance measurements reveal a capacitance ratio of 4 and are in agreement with simulation results. A voltage gain of 2.4 is demonstrated. The device is suitable for energy harvesting from low-frequency high-amplitude ambient motion sources such as the human body.