Bandwidth Increment of Piezoelectric Energy Harvester using Multi-beam Structure

Piezoelectric energy harvesters have high power density and are simpler to fabricate as compared to other low power energy harvesters. There are certain issues which need to be addressed while designing a piezoelectric energy harvester. These are the requirements of maintaining a high output voltage, low resonant frequency, small size and wide bandwidth of operation. Achieving a wide bandwidth is one of the most prominent issues. It is because most of the vibrations occur over a range of frequencies. So, the challenge is to design an energy harvester which generates high output voltage over a wide range of frequencies. In this paper, a Microelectromechanical system (MEMS) based multi-beam energy harvester has been proposed. This energy harvester has been designed using two single cantilever beams and the top electrodes of both the beams are connected by a metal layer. The peak output voltage of the proposed structure is 18 V at 142 Hz. The multi-beam structure generates an output voltage of more than or equal to 5 V for a bandwidth of 15 Hz which is 1.5 times wider as compared to that of a single beam energy harvester.