Investigation the Effect of Misalignment and Distance between the Coils for Wireless Power Transfer in Retinal Implants

Powering retinal implants with a battery contrary to many neuroprosthetic devices is one of the greatest difficulties encountered for both design and implantation phase. Considering there are limitations on space and volume in intraocular region with extra risks for replacement surgeries, inductive coil links, which use near-field resonant inductive coupling with the mutual inductance between primary and secondary coils, attract considerable attention to reliably transfer the necessary power to retinal implants wirelessly. Retinal prosthesis requires continuous power transfer to process real time images into stimulation patterns, so high power transfer efficiency plays a critical role. In this work, we examined the effect of misalignment of the coils and the gap distance between coils on coupling coefficient solving the equations by custom-written MATLAB codes followed by Finite Element Method. It was seen that coil misalignment and distance between coils showed similar impairing effects on coupling coefficient.