Path loss modeling for UWB creeping waves around human body

Abstract

This article presents path loss models for creeping waves propagation around a human body at ultra-wideband frequency of 2-8 GHz. The results are based on measurements in an anechoic chamber using a vector network analyzer. Three antenna types are used: prototype dipole and double loop antennas together with the commercial Skycross antenna. The antennas are attached horizontally at the chest level and the waist level at in total 12 locations. Path loss values are defined from the first arriving paths of the channel impulse responses. Path loss models are developed for upper and lower horizontal body levels separately and for all available channels when also the cross channels between the levels are considered. The path loss exponents vary between 9.2-12.7 being clearly a higher result than previously reported. The double loop antenna has the lowest exponents and the commercial antenna the highest ones. No clear difference can be noted between the body and waist levels or when observing all channels. The scattering term of the path loss can be modeled with the generalized extreme value and generalized Pareto distributions.