Towards analytic path loss models in on-body wireless communications

There is a significant trend towards on-body wireless networks in both, consumer electronics and bio-medical applications. Like any other wireless system its design depends heavily on the radio channel. In contrast to free space communications there are not many channel models available and the few are statistical models that allow only for limited physical insight. Therefore, an analytical model that is based on the physics of on-body radio wave propagation combined with statistical parameters to account for the variety of the human body anatomy would be highly desirable. In this research, we evaluate the feasibility of analytic on-body path loss models in wireless body area networks based on Norton surface waves. The evaluation is based on a refined formulation of Norton surface waves (Norton, 1937) excited by an antenna near dissipative media by Bannister (Bannister, 1984) and its applicability to the constitutive parameters of different body tissues at typical operation frequencies of on-body wireless applications (0.4 <; f[GHz] <;60). The numerical verification is based on homogeneous flat body scenarios. This is followed by examples of propagation paths on an inhomogeneous anatomically correct human body model. As the Norton theory is based on a flat propagation scenario the effect of the curvature of the body has to be introduced by corrective terms for the ground wave and the Norton surface wave, respectively. The results obtained are promising with respect to the development of analytic path loss modes for on-body wireless propagations.