Efficient Space Utilization of Magnetics for Wireless Energy Harvesting in Volume-Constrained Applications

Magnetic materials are widely utilized in induction-based wireless energy harvesting for MEMS. However, the volume of these magnetic materials often comprises a large fraction of the total volume of the MEMS device; this can be challenging in many applications where the overall volume of the device is constrained by application. We present a new geometry of a wireless energy harvester (WEH) magnetic core that achieves a 43% volume reduction compared with a single solid core, while largely maintaining total harvested energy, thus improving output power density per unit volume of magnetic material by approximately 80%. The WEH design features a centrally vacant hollow magnetic core with the core sidewalls wound by two series-connected solenoids. The central hollow region is thus available for integration of other components, providing an efficient solution for volume-constrained applications.