Body-Resonance Human Body Powering

The growing demand for the perpetual operation of body-connected devices and distributed sensor nodes, along with an exponential reduction in the size of computing units, has highlighted the need for novel wireless powering solutions for wearable devices. Over the past two decades, the use of the human body as an energy-efficient alternative to radio wave-based techniques for wireless communication, particularly in the Electro-Quasistatics (EQS) region, and more recently, the concept of body-coupled power transfer has gained considerable attention. Moreover, revealing the advantages of the Body Resonance (BR) regime over EQS, recent studies demonstrated the potential for designing power-efficient body-coupled communication systems for Body Area Network devices. However, a comparison of the wirelessly transferred power through the human body between the EQS and BR regimes has not been presented in the literature. In this paper, we present a comparative analysis of the variation in received power between EQS and BR. Highlighting the benefits of wirelessly charging portables/wearables by transferring power through the human body while remaining below the safety limit, we analyze a Machine-to-Wearable scenario that can provide higher on-body voltage and consist of a floor-based, ground-connected power transmitter and a portable receiver in BR frequencies. The results show that the BR regime improves the received power ($\sim \text{1 0 0} \mu \mathrm{W}$ over $>\text{1 ~ m}$) by $\sim \text{2 0 0 X}$ compared to the EQS scenario and has the potential to wirelessly charge low-medium power physiological sensors, fitness trackers, etc.