Wireless Implant Communications Using the Human Body

Abstract

This chapter first examines a new analytical electromagnetic model that uses galvanically coupled intrabody communication (IBC). Frequencies ranging from hundreds of kHz up to a few MHz are considered under quasi static assumptions. The model is unified in the sense that it can be applied to any part of the body (i.e., head, torso, limbs etc.). It also describes influences of tissue property and geometry of the body part. The security and low power consumption of IBC are also apparent in this model. The path loss characterisation of IBC implants shows lower values compared to their MICS counterparts. In addition, the chapter also elaborates on the use of human body as antenna. A scenario where an RF current is fed by a tiny toriodal inductor clamped around tissues in the ankle is studied. The frequency range of 1-70 MHz is considered. Theoretical results show that the system has a maximum gain of - 25 dB between 20 to 40 MHz, assuming an isotropic radiation from human body. For improved performance, mitigation techniques for losses are also discussed.