Bistable springs for wideband microelectromechanical energy harvesters

This paper presents experimental results on a microelectromechanical energy harvester with curved springs that demonstrates an extremely wide bandwidth. The springs display an asymmetrical bistable behavior obtained purely through their geometrical design. The frequency down-sweep shows that the harvester 3-dB bandwidth is about 587Hz at 0.208-g acceleration amplitude. For white noise excitation at 4 x 10(-3) g(2)/Hz, we found that the bandwidth reaches 715Hz, which is more than 250 times wider than in the linear-spring regime. By varying the bias voltage, an output power of 3.4 mu W is obtained for frequency down-sweep at 1-g amplitude and 150-V bias. (C) 2013 American Institute of Physics. [http://dx.doi.org/10.1063/1.4775687]