Design and Optimization of Efficient Wireless Power Transfer Links for Implantable Biotelemetry Systems

Wireless power transmission is a technique that converts energy from radio frequency (RF) electromagnetic (EM) waves into DC voltage, which has been used here for the purpose of providing a power supply to bio–implantable batteryless sensors. The main constraints of the design are to achieve the minimum power required by the application, by still keeping the implant size small enough for the living subject’s body. Resonance–based inductive coupling is a method being actively researched for the use in this type of power transmission, which uses two pairs of inductor coils in the external and implant circuits. In this work, we have employed the resonance–based inductive coupling technique in order to develop a design and optimization procedure for the inductors. We have designed two systems with different configurations, and have achieved power transfer efficiencies of around 80% at a coil distance of 50mm for both systems. We have also optimized the power delivered to the load (implant) and developed a power harvesting unit. Misalignment issues due to the subject’s movements have been modeled for calculating the worst–case alignment, and finite element modeling of the inductors has been performed.