A High-Performance Electrodynamic Micro-Receiver for Low-Frequency Wireless Power Transfer

We report the design, fabrication and characterization of a microfabricated electrodynamic wireless power transmission (EWPT) receiver that uses a bulk-micromachined silicon serpentine torsional suspension, NdFeB magnets, and precision-manufactured micro-coils. The 0.31 cm
³
device generates 2.46 mW average power (7.9 mW/cm
³
) at a distance of 4 cm from a transmitter coil operating at 821 Hz and safely within allowable human exposure limits. Compared to a previously reported prototype, this micro-receiver is ~40% smaller, offers ~16x better magnetic field sensitivity and 1.7x higher power density for improved applicability for wirelessly charging wearable and bio-implantable devices.