An Electrodynamic Wireless Power Receiver ‘Chip’ for Wearables and Bio-implants

This paper presents the design, fabrication and experimental characterization of a chip-sized wireless power receiver for low-frequency electrodynamic wireless power transmission (EWPT). Utilizing a laser micro-machined meandering suspension, one NdFeB magnet, and two PZT-SA piezoelectric patches, this 0.08 cm
³
micro-receiver operates at its torsion mode mechanical resonance of 724 Hz. The device generates 360 μW average power (4.2 mWcm
^-3
power density) at 1 cm distance from a transmitter coil operating at 724 Hz and safely within allowable human exposure limits of 2 mTrms field. Compared to a previously reported macro-scale prototype, this volume-efficient micro-receiver is 31x smaller and offers 3.2x higher power density within a low-profile, compact footprint for wirelessly charging wearable and bio-implantable devices.