Analysis of Impact of Bioimpedance on Implant Coil of Artificial Retina for Improving Quality Factor and Bandwidth

Abstract

Miniaturized coils are an indispensable part of implantable electronics for facilitating newlinewireless power and data transfer. The use of the implant coils enables efficient newlineand reliable power/data transmission between the implant and external devices. The newlinefrequency and physical parameters of the coils are carefully chosen to optimize performance newlinemetrics such as quality factor and resonant frequency of the coil, thus ensuring newlineeffective energy transfer, minimizing interference, and complying with safety regulations. newlineThe primary objective of the research work is to analyze the quality factor and newlineresonant frequency of the implant coil in biological settings at higher frequencies in newlineorder to clearly visualize the impact of surrounding tissue on the implant coil. Highfrequency newlineimplant coils are vital parts of the wireless data transfer system of implantable newlineelectronics for achieving higher data rates. Coil structures are optimized to resonate the newlinecoil at a higher frequency using a parametric approach. The key challenges associated newlinewith the disparity in coil characteristics after implantation in the eye are being investigated newlinein this work. newlineThe second objective is to improve the performance of the implant coil in heterogeneous newlinetissue media by investigating the resistive and capacitive effects of the ocular newlinelayers that surround the coil. The bioimpedance of eye layers such as the cornea, newlineaqueous humor, and the lens is modelled to analyze the resistive-capacitive behavior of newlinetissue for the designed operating frequency of the coil. A prototype of the human eye newlinethat sources non-linear effects of tissue to the implant coil is modelled in HFSS. The newlineultra-thin circular coil of 0.8 mm is modelled, integrated, and simulated in the prototype newlineto study the performance of the implant for various test cases. To validate the simulated newlineresults, the fabricated coil is implanted in the porcine eye to mimic the actual test bed. newlineThe implant coil was analyzed for various test cases in tissue medium, thus aiding to device.