ELECTROSTATIC MICRO POWER SCAVENGER WITH DUAL CAVITIES

We have designed, modeled, fabricated and tested a novel 2×2 mm 2 MEMS electrostatic power scavenger with dual capacitive cavities for vibration to electric energy harvesting. The device is unique in the use of a dual-cavity design and electroplated nickel as main structural material. When the capacitance increases for one cavity, it decreases for the other. This allows using both up and down directions to generate energy. Comprehensive dynamic simulations of the devices were performed using Matlab, which assuming the movable plate is allowed to have translational degree of freedom with rocking instability. The devices have been successfully fabricated using surface micromachining and experimentally characterized using a PCB test board mounted on a shaker and a NI USB-6218 DAQ controlled by Labview. The resonance of the device was observed around 500 Hz. A maximum power of 225 nW was achieved under a high DC bias of 15 V and intense excitation above 5 g.