Room-Sized Helmholtz-Type Resonator for Ubiquitous Wireless Power Transfer

This study introduces a Helmholtz-type resonator for wireless charging low-power devices in a room-scale environment. A unique feature of this resonator is a uniformly magnetic field distribution, reaching 91.1% coverage within 1/4 of the resonator's internal volume. This maintenance of high magnetic field uniformity contributes to a stable power transfer efficiency (PTE) as observed in simulations, exhibiting only minor fluctuations within the range of 5.6% to 8.3%. Our experimental investigation successfully demonstrated the wireless charging of various devices, including a fan, smartphone, nightlight, and lamp, achieving an overall PTE of 12%. Furthermore, our findings indicated that the specific absorption rate values remained below the stipulated safety thresholds regarding the safety regulations outlined in the IEEE Std C95.1™-2019. The proposed volumetric resonator presented in this study represents a significant advancement, as it promises to elevate the concept of smart home technologies, enabling multiple individuals to access a charging infrastructure for their electronic devices without sacrificing mobility. Additionally, this innovation offers a convenient solution for integrating electrical devices within room interiors.