Dual-Transduction Electromechanical Receiver for Near-Field Wireless Power Transmission

We report the design, fabrication, and experimental characterization of a chip-sized electromechanical micro-receiver for low-frequency, near-field wireless power transmission that employs both electrodynamic and piezoelectric transductions to achieve a high power density and high output voltage while maintaining a low profile. The 0.09 cm
³
device comprises a laser-micro-machined titanium suspension, one NdFeB magnet, two PZT-5A piezo-ceramic patches, and a precision-manufactured micro-coil with a thickness of only 1.65 mm. The device generates 520 μW average power (5.5 mW·cm
^-3
) at 4 cm distance from a transmitter coil operating at 734.6 Hz and within safe human exposure limits. Compared to a previously reported piezoelectric-only prototype, this device generates ~2.5x higher power and offers 18% increased normalized power density (6.5 mW·cm
^-3
·mT
^-2
) for potential improvement in wirelessly charging wearables and bio-implants.