Intra-body communication channel characterization and modeling

To fully realize the potentials of the sensors in a personal healthcare system, body area network (BAN) is developed. Existing wireless sensor network technologies are not suitable for BAN because they are not designed to minimize the power of the sensors and they do not scale well for a heterogeneous network. Intra-body communication (IBC), which uses the human body as the communication media, is a promising physical layer implementation for BAN in personal healthcare systems. It provides low-power, high-speed and reliable communication links. According to the signal transmission mechanism, IBC can be categorized into EM IBC and EF IBC. EM IBC has low power efficiency and limited bandwidth. The EF IBC, composited by a forward body path and a parasitic return path, has high power efficiency and large bandwidth. In this thesis, EF IBC channels are characterized and modeled. A critical issue in EF IBC is the separation of TX and RX grounds, because in most applications the TX and RX are battery-powered. Three characterizations setups are developed: 1) VNA with baluns; 2) TX board and SA; and 3) TX and RX board. S21 measured by the VNA with baluns setup shows a band-pass profile while the channel gain measured by the latter two setups shows a high-pass profile. Body channel radiation and body captured interference are also measured with the TX and RX board setup. Discussions of the results are provided FEM models of the first two characterization setups are established. Simulations reveal that the parasitic return path of the IBC channel is complicated. Simulation results using the FEM model of the TX and SA setup fit the measurement results well. Conclusions and future work are presented at the end of the thesis