A Coil Rectenna Array Design to Harvest All H-Field Components for Lateral Misalignment Tolerant Wireless Powering of Bio-Medical Implant Devices

This paper presents a coil rectenna array design to address the lateral misalignment problem in near-field wireless powering of biomedical implants and wearable devices. For this purpose, the proposed design comprises three non-identical orthogonal coil antennas optimized to harvest three orthogonal H-field components efficiently. The rectified energy generated by these antenna units is utilized to supply power to the load by combining the individual rectified output voltages. Out of the two distinct combining techniques, DC and AC combining, DC combining proved advantageous in effectively harnessing the lateral field components. The design parameters of the orthogonal coil rectennas are optimized to enhance the lateral misalignment tolerance area. To realize the proposed rectenna array, a multi-layer PCB technology is employed, resulting in a compact, robust, and cost-effective solution for wireless powering of biomedical implanted and wearable devices. Experimental validation of the analytical results demonstrates that the proposed design has the potential to significantly mitigate the lateral misalignment problem in a 2D plane, achieving a uniformity percentage of $\boldsymbol{38.18}$ % for a misalignment tolerance range of $60\times 60$ mm $^{2}$ .