Norton Surface Waves in the Scope of Body Area Networks

This paper presents an evaluation on how Norton surface waves can be used to analytically model the on-body propagation in wireless body area networks. Based on a brief review of the Norton surface wave theory, the general problem as defined for terrestrial propagation by Sommerfeld, is unified taking into account the further extensions by Norton and Bannister which motivates its evaluation for on-body propagations. A discussion of Sommerfeld's numerical distance reveals useful properties to evaluate the capability of a certain configuration to excite Norton surface waves in specific on-body scenarios. Based thereon antenna design guidelines for on-body propagation links can be derived. All investigations are carried out for human muscle, skin, and fat tissues in the frequency range from 0.4 GHz to 60 GHz. A comparison of the simplified model consisting of a planar homogeneous ground to a realistic inhomogeneous human body model shows good results for the attenuation of the electric field strength along the on-body path.