A MEMS Electromagnetic Vibration Energy Harvester with Monolithically Integrated NdFeB Micromagnets

Abstract The monolithic integration of high‐performance magnets into microfabricated devices remains a technological challenge despite the great interest for telecommunications, automotive, biomedical or space applications. Here the integration of 50 µm thick sputtered arrays of NdFeB micromagnets into a functional micro‐electro mechanical system (MEMS) in‐plane electromagnetic vibration energy harvester is reported. A combination of analytical modeling and numerical simulations guided the design of the magnet arrays along with ad‐hoc planar coils, to produce a high transduction factor. The resulting energy harvesters deliver a voltage of 2.5 mV, a power of 6 nW under an acceleration of 0.8 g and a normalized power density of 3 × 10 ⁻⁴ kg s m ⁻³ (20 mW m ⁻³ ) for a device volume of roughly 300 mm ³ , which is comparable to state‐of‐the‐art MEMS electromagnetic vibration harvesters. This study serves as a show‐case for the possibility of integrating high‐performance micromagnets into functional devices using microfabrication processes.