45% RF-to-DC Conversion Efficiency Wireless Power Transfer System Through Biological Tissues Using Complex Conjugate Impedance Matching Taking Account of Tissue’s Properties
This paper presents a complex conjugate impedance matching technique taking account of the electric properties of biological tissues during power transfer. Output impedance of a wireless power transfer (WPT) system depends on the electrical property of tissues where the system is being used. So, impedance mismatch between Rx and rectifier occurs when the system optimized for air is used in biological tissues. First, the system is matched in the air and later, impedance mismatch is estimated when the same system is being used in chicken which is later compensated. The proposed matching technique will bring back the rf-dc power conversion efficiency (PCE) very close to that of the system being used in the air. Experiment was carried out in three different cases where PCE is 49.53% in the air, 30% in chicken with the conventional conjugate matching and 45.5% in the chicken using the proposed matching technique.