Use of the Thin-Strut FDTD Formalism for the Design of Coils in Biomedical Telemetry Applications.

Abstract

For many years, inductively coupled telemetry systems have been designed and used for transcutaneous energy transfer in biomedical applications. But most of these designs are mainly based on steady state circuit analysis. To our knowledge, no specific computational electromagnetic techniques have been developed to analyze the coupled systems. This thesis extends the thin-strut FDTD formalism to study the coupling of an external primary coil and an implanted secondary coil in the biomedical telemetry applications. The stability and convergence analyses are discussed, from the unconditionally stable semi-discrete field-wire system to the conditionally stable fully-discrete system. A new stability criterion for selecting the time step is introduced. Computational experiments demonstrate the effectiveness and the accuracy of this extension, provided that the time step is properly chosen.