In vivo wireless communication channels

In this paper we perform signal strength and channel impulse response simulations using an accurate human body model and we investigate the variation in signal loss at different RF frequencies as a function of position around the human body. It was observed that significant variations in received signal strength (RSS) occurred with changing position of the external receive antenna at a fixed distance from the internal antenna. The variations were even more profound at the highest frequency, where just a 5° of movement causes an increase of RSS up to 20 dB. Wideband scattering parameters were also obtained and the channel impulse response was calculated. A greater amount of dispersion through the abdomen has been observed than was expected based on human body geometry.