Radiation Pattern of Wearable Antennas: A Statistical Analysis of the Influence of the Human Body

This paper explores a statistical approach for modelling antennas’ behaviour in the vicinity of the human body. The statistics of radiation patterns, i.e., average and standard deviation, have been calculated for Uniform and Rayleigh distance Distributions of the antenna to the body. The coupling between the body and the antenna, and the reduction of antenna efficiency, lead to a distortion of the radiation pattern, which depends on the distance as well as on the location on the body. A patch antenna operating at 2.45 GHz, on the head, chest, arm, and leg was simulated in computer simulation technology (CST), using a voxel model. Results show that the relative change of the average radiation pattern for an antenna located on the chest can reach 24 %. The study was complemented with measurements, showing that, in the area of interest for on-body communications, an average difference between CST and measurements of 0.9 dB is found which can be considered very good.