Improved performances of wideband MEMS electromagnetic vibration energy harvesters using patterned micro-magnet arrays

Abstract

The ubiquitous ambient vibrational energy is a potential candidate for solving the pertinent issue of perpetual powering of the numerous deployed wireless sensor nodes. The major roadblock in the materialization of a fully integrated high-efficiency electromagnetic vibration energy harvester is the lack of CMOS compatible magnetic materials and its integration. This work demonstrates the unique advantage of employing high performance stripe patterned array of magnets instead of conventional thin film of magnets which enhances the electromagnetic coupling factor to 53.03 mWb/m by maximizing the magnetic flux gradient within a small footprint and in a precise location. Further, it explores the benefits of employing compact in-plane moving nonlinear MEMS spring architecture, which till date is relatively unreported, that enhances the bandwidth of operation 3 times as compared with its linear counterpart at the cost of reduced peak load power. This detailed study provides a design guideline and opens up the scope for further design optimization for improving overall performance of MEMS Electromagnetic Vibration Energy Harvesters (EM-VEH).