EM radiation behavior upon biological tissues in a radio-frequency power transfer link for a cortical visual implant

This paper presents a method to evaluate the interactions between a radio-frequency power transfer link and biological tissues. First the authors analyze the propagation of a plane wave model at the skin interface to evaluate the frequency that optimize the transfer ratio. They then use the Finite-Difference Time-Domain method to calculate the exact electromagnetic fields propagation in a discrete 3D space and time for a box brain model with an inductive emitting antenna. The results exhibit the electric field pattern in the antenna axis plane and in the back of the head. They show for an optimized frequency carrier (20 MHz) that the attenuation of electric field strength is 15 dB and that most of the energy is reflected at the air-tissue interface