A high performance electrostatic MEMS vibration energy harvester with corrugated inorganic SiO2-Si3N4 electret

This paper presents the design, fabrication and characterization of a MEMS vibration energy harvester for tire pressure monitoring applications (TPMS). It is based on a SiO₂-Si₃N₄ electret compatible with CMOS processing, thus allowing low cost production for large volumes. The device has a footprint of about 1 cm². When excited by a sinusoidal vibration, the device generates a maximum AC power of 160 μW. This is one of the highest reported values for MEMS fabricated vibration energy harvester based on an electrostatic transduction mechanism. When excited by a vibration with characteristics similar to that measured in a tire, the maximum raw power is between 10 and 50 μW, which is sufficient to power a simple TPMS module. Furthermore, in contrast to most of electrostatic harvesters, our device exhibits a linear electromechanical behavior, due to its particular design. This simplifies greatly the modeling, optimization and experimental characterization of the device.