High Efficiency Wireless Power Transfer System Using Spiral DGS Resonators Through Biological Tissues

This paper presents a wireless power transfer (WPT) system to transfer power through the tissues using Defected Ground Structure (DGS) resonators. The proposed DGS resonator is made of a spiral structure at the ground plane to increase the quality (Q-) factor, and when two DGS resonators are coupled back to back, it transforms to a bandpass filter resulting in the wireless power transfer. Experiment on the proposed WPT system shows an efficiency of 67.7% in air and 61% when placed in the tissue environment at 20MHz frequency.