Wireless Power Transmission with Uniform Power Delivery in the 3D Space of the Human Body using Resonators in Parallel

This paper presents a novel resonance-based multi-coil wireless power transmission (WPT) system for powering implantable devices inside the 3D space of the human body. This design consists of a power amplifier, a transmitter coil, a cluster of resonators in parallel configuration, and a receiver unit, working at 13.56 MHz (the FCC-approved ISM-band). The proposed cluster configuration of the resonators in parallel configuration guarantees homogenous electromagnetic fields and uniform wireless power distribution in the 3D space of the body. It localizes the transmitted power at the receiver location naturally by activating the resonators near the receiver. We have modeled the proposed inductive link and the human body with HESS software to optimize the design and study the body's safety by evaluating the Specific Absorption Rate (SAR) level. The proposed WPT system is implemented, and the measured results show that the inductive link with multiple resonators in parallel configuration can continuously deliver power, >120 mW, wirelessly inside the 3D space of the human-torso with a power transfer efficiency (PTE) of 15%, uniformly. We have also extended the coverage area to the human forearm by paralleling resonators with the resonators in the central body. The power delivered to the load and PTE between the resonators on the forearm area are measured >90 mW and similar to 14%, respectively.