Performance Improvement of MEMS Electromagnetic Vibration Energy Harvester Using Optimized Patterns of Micromagnet Arrays

Abstract

Scavenging mechanical energy from ubiquitous vibrations through miniaturized electromagnetic (EM) transducers is a potential solution to the problem of powering wireless sensor networks for the Internet of Things (IoT). This letter presents the design and performance analysis of fully integrated EM vibration energy harvesters on the scale of microelectromechanical systems (MEMS). Through analytical formulation and finite element analysis, we present a systematic design study to optimize the magnet-coil interaction in a precise location within a small surface area (“footprint”). The compact device topology yielded an EM coupling as high as 62.9 mWb/m with optimized stripe-shaped micromagnets and rectangular microcoils. The nonlinear spring topology demonstrated six times improvement in the half-power bandwidth compared to its linear counterpart, at a cost of reduced power density. The designs can be implemented using standard MEMS fabrication methods leveraging CMOS-compatible integration at the system level for potential applications in the IoT.