A Wireless Power Transfer System (WPTS) Using Misalignment Resilient, On-Fabric Resonators for Wearable Applications

In this paper, we demonstrate a fabric-integrated, near-zone wireless power transfer system, which uses a newly developed misalignment resilient antenna element for inductive power transfer in wearable applications. The antenna consists of an anchor-shaped geometry, which uses a combination of electric and magnetic field couplings in the near field to achieve high power transfer efficiency (PTE) of 85% even under lateral misalignment. Improvement in PTE for lateral and angular misalignment cases is demonstrated which facilitates the near-zone power transfer for practical usecases. For fabric integration, the proposed antenna and rectifier system were fabricated on a textile substrate by using conductive thread embroidery. We report the PTE of the developed antennas variation with different types of misalignment cases. For lateral misalignment, the proposed antenna exhibited an average PTE of 85% for lateral movements of 1 to 10 cm. Furthermore, the antennas exhibited an average PTE of 70% for elevation and 60% for azimuthal misalignment cases. These results are compared with circular loop resonator illustrating the improvements in the PTE. Using this antenna element, power harvesting system and its resilience to misalignment are also demonstrated.