Efficient and Flexible Huygens' Source Replacement of mm-scale Human Brain Implants

Abstract

Implants for monitoring or stimulation of nervous activity in the human brain offer multiple challenges for electromagnetic compatibility. Both the electromagnetic emission into the surrounding brain tissue and the electromagnetic interference with other implants have to be tightly controlled. From a computational perspective the hierarchical structure and the frequency dependence of the brain tissue as well as the high aspect ratio between implant features and the size of the brain offer multiple challenges. Here, we propose an approach based on the Huygens' principle in combination with a method of moments to overcome part of these challenges with respect to the computation of possible interference between implants. The approach makes use of the fact that due to high losses in the brain tissue at frequencies below 1 GHz the interaction between implants can be characterized as weak coupling. Apart from being computationally more efficient the proposed approach is also flexible in the sense that different victim implants can easily be computed. Results for a realistic head model show good agreement between this approach and a traditional full-wave simulation.