Multi-Axis Inertial Energy Harvester Based on Piezoelectric Crab-Legs with Partitioned Electrodes

This paper reports a microfabricated piezoelectric MEMS inertial energy harvester that can scavenge high-frequency mechanical vibrations in all three dimensions with an active inner volume of only 55 mm3. The device can generate 0.1 to 10.5 mu W from out-of-plane vibrations (365-465 Hz), and 0.1 to 3.2 mu W from in-plane vibrations (680-930 Hz) at 0.5 g acceleration input. The reported harvester is demonstrated to be effective for multi-axis operation, with a favorable power density of 0.2-2.2 mW/cm(3)/g(2) (at 0.1-0.5 g) with respect to previously reported microfabricated multi-axis vibration harvesters.