A statistical approach to model antenna radiation patterns in off-body radio channels

The goal of this paper is to introduce a statistical approach for modelling antennas behaviour in the vicinity of the human body. A very preliminary model based on geometrical optics has been developed, and calculations have been performed for parallel and perpendicular polarisations, for 0.915, 2.45 and 5.8 GHz, for various human body tissues, and for several antenna locations on the body. The statistics of radiation patterns, i.e., average, minimum, maximum and standard deviation, have been calculated for Uniform and Rayleigh antenna to body distance distributions. The results show a much higher variation of changes among various frequencies of average radiation patterns for the Rayleigh distribution, which can reach 60%, while for the Uniform one, it can go up to 30%. When modelling various tissues, the results show that the average radiation pattern is changing no more than 15%, but the change of standard deviation can reach 70%.