Antennas, Wave Propagation, and Localization in Wireless Body Area Networks

A network of communicating wireless devices that are implantable, wearable or within close proximity of a human body is called wireless body area network (WBAN). The propagation channels for the devices in the WBAN are either through the body or over the body. This results in the attenuation and the absorption of electromagnetic waves radiated by the antenna of these devices due to the lossy tissues of the body. With a proper antenna and knowledge of the signal loss between the devices in the WBAN, a reliable wireless link can be designed. This thesis presents the investigations done for the antennas, wave propagation, and localization for various applications of these networks. The investigated applications are: (1) Binaural Hearing Aids (Paper I \& Paper II), (2) Sensor placed Around the Body (Paper III \& Paper IV), (3) Localization of Wireless Capsule Endoscope (Paper V), and (4) In-Mouth Devices. Binaural hearing aids communicate with each other for synchronization such as adjustment of volume or programing for the listening environment. In Paper I, antennas suitable in size and technical performance at 2.45 GHz for in-the-ear (ITE) and in-the-canal (ITC) placement of the hearing aids are presented. The ear-to-ear link loss found from the finite-difference-time-domain (FDTD) simulations for the ITE case was 48 dB and that for the ITC case was $92$~dB for the SAM head. The ITE case was further investigated on realistic heterogeneous phantoms of different age and head sizes. The link loss in the ITE case for an adult heterogeneous phantom was found to be $79$~dB. It was found that the absence of the pinna (outer ear) and the lossless shell under-estimates the link loss for the SAM phantom. Hence, a phantom with the lossy outer shell and the pinnas should be used for a proper estimation of the ear-to-ear link loss. In Paper II, an analytical model is presented for the ear-to-ear link loss based on the attenuation of the creeping wave over an elliptically modeled c