A Picowatt Energy Harvester

Abstract

The authors describe an energy harvester circuit fabricated with integrated thin ferroelectric film capacitors on a silicon substrate. The harvesting mechanism is a folded double-beam cantilever with proof masses at both end points. Interdigitated electrode capacitors are located at the three points on the folded cantilever that are expected to experience maximum bending moment and should produce up to 5V as a function of external vibration. The die has the dimensions of 1.6mm on a side and is designed to be mounted in a TO-18 package transistor-style package. Due to its small size, the self-contained piezoelectric MEMs device should produce 50 picowatts in a 1g vibration environment while occupying little space.