Modelling, Simulation and Investigation of Wireless Power Transfer in Square-loop Chip at UHF Band for Medical/Biomedical Charging

Abstract

Medical electronics (Implant) devices are important in daily lives of the sick patient with terminal infections. The recent discovery of wireless power transfer (WPT) technology provides a gateway for the noncontact electricity transmission for multiple gadgets and medical implantable devices such as (artificial heart, sphincter, defibrillator and electrical simulator) simultaneously. Wireless power transfer is the transfer of power between a transmitting module and a receiving module of different system. In this work, we designed, modelled and analyzed the effects of orientation, alignment as well as coupling losses of a transmitting and receiving antenna. We designed the antenna by determining the frequency of operation (f 1 ), dielectric constant of substrate (ε r ), the substrate height (h), loop length, width using the fundamental mode. Simulation of the wireless power transfer system was accomplished using the electromagnetic system COMSOL Multiphysics 5.5 model at a frequency domain of 1.8MHz. The model consists of two printed square loop antenna enclosed by an air domain with perfectly matched layer (PML). The etched layer is patterned on 2mm Polytetrafluoroethylene (PTFE) board, the thickness of the copper layer used varies geometrically, but much thicker than the copper skin depth, so that it is modelled as a perfect electric conductor (PEC). Results obtained from the simulation shows a strong coupling at 0, 22.5, 45, 67.5 degrees and a hot coupling around the receiving antenna at angle 90 degrees. These results indicate the device can only be used for direct charging.