Modeling and Characterization of in-Body Antennas

Abstract

Emerging wireless in-body devices pave the way to many breakthroughs in healthcare and clinical research. This technology enables monitoring of physiological parameters while maintaining mobility and freedom of movement of its user. However, establishing reliable communication between an in-body device and external equipment is still a major challenge. The radiation efficiency is constrained by attenuation and reflection losses in tissues. Furthermore, the antennas suffer from impedance detuning issues caused by uncertain electromagnetic properties of body tissues. First, we show that choosing an optimal operating frequency depends on application scenarios and can reduce the losses. Specific designs are then discussed to mitigate the antenna detuning effects due to surrounding biological tissue. Modeling approaches are proposed to lessen the design and optimization complexity. Finally, we present an accurate characterization method of in-body antennas in canonical phantoms using analog fiber optic links.