Numerical Characterization and Link Budget Evaluation of Wireless Implants Considering Different Digital Human Phantoms

This paper presents a numerical investigation of the radiation characteristics of gastric, bladder, and cardiac implants based on the finite-differences time-domain method. Simulations were performed at the medical implanted communication services (MICS) and the industrial, scientific, and medical radio bands, respectively, using three different digital inhomogeneous human phantoms (two male and one female models). The numerical analysis demonstrated that the radiation performances are strongly dependant on the location of wireless implants, as well as the body mass index of the subject. The results highlighted the significance of subject specific modeling when designing wireless implants. A link budget calculation was proposed for the communication between a left-ventricular wireless implant and an off-body base station as an example for MICS applications. It is demonstrated that, due to the presence of human tissues, the antenna radiation from wireless implants tends to be directive, and therefore, the signal-to-noise ratio in communication links is strongly dependent on the orientation of the human subject with respect to the base station.