Broadband power enhancement by multimodal coupling in a MEMS dual-cantilever piezoelectric energy harvester

Abstract

This work reports a dual-cantilever-coupled multimodal piezoelectric energy harvester (DCC-PEH) designed for enhanced broadband power generation. By kinematically integrating a low-frequency cantilever and a high-frequency cantilever through a shared tip mass, the device leverages mechanical coupling to bridge modal gaps. Fabricated via a thick-film piezoelectric MEMS process on a flexible metal substrate, the DCC-PEH exhibits superior electromechanical conversion. Under 1.0 g excitation, it achieves peak powers of 154.4 and 261.1 μW at 464 and 523 Hz, respectively, with an effective bandwidth of 100.5 Hz. Notably, the DCC-PEH yields a normalized power density up to 2.16 mW cm−3 g−2, representing a 75.6% increase in power density and a 44.2% bandwidth expansion compared to the uncoupled dual-cantilever configuration. This synergistic coupling effectively suppresses off resonance dormancy, providing a compact and robust energy solution for self-powered wireless sensor nodes.