Authors: S. Kim, O. Scholz, K. Zoschke, R. Harrison, F. Solzbacher, M. Klein and M. Toepper
Affilation: Fraunhofer Institute for Biomedical Engineering, Germany
Pages: 705 - 708
Keywords: microcoil, FEA, finite element analysis, telemetry, implant
To wirelessly transfer energy into active biomedical devices such as neural stimulators or bio-monitors implanted in the body, magnetic coupling of a pair of coils has been commonly used. The growing demand for highly miniaturized medical implants requires also the implant coil to become smaller. The size of coils can be drastically reduced with the aid of micromachining technologies that enables to manufacture coils with structure dimensions in the µm-range. In order to design this kind of coils, an exact modeling and prediction of their electrical characteristics is essential. This paper describes how the electrical characteristics of microcoils were modeled through field simulations based on finite element analysis methods. Besides the basic parameters – inductance and series resistance, also high frequency effects such as the skin and proximity effects as well as parasitic capacitances were investigated. The simulation methods were verified by measurements performed with a number of fabricated sample coils. Based on the simulation results, strategies to design microcoils are suggested in the viewpoint of energy transmission efficiency.