An Analytical Model for Inductively Coupled Multichannel Implantable System With Micro-Coil Array

Implantable system is widely used for functional electrical stimulation to repair the damaged nerve function. We propose a multichannel wireless implantable system using micro-coil array to implement parallel signal transmission based on inductive coupling, which meets the increasing requirement of some implantable system for high data rate and high power efficiency. However, the magnetic coupling among carrier from different channels will affect the operation of each link. In this paper, this interference is analyzed and design equations are derived, which are used to design coils, arrange their position and apply carrier for each channel to maximize the data signal level received at the implant side. A prototype of multichannel system has been built and experimental results show that data can be transmitted parallelly and high data rate can be achieved. This theoretical calculation verifies the feasibility of using the micro-coil array to achieve multichannel transcutaneous transmission for neural electrical stimulation.