Analysis of Dynamic On-Body Communication Channels for Various Movements and Polarization Schemes at 2.45 GHz

Abstract

On-body wireless communication channels are studied by using the finite-difference time-domain (FDTD) method and moving human models. An anechoic environment is assumed. Three movements having a different dynamical characteristic each, walking, weakly walking and running, are considered. Essentially, the results are obtained for nine different polarization schemes regarding the dipole transmitter and receiver orientations and for six receiver locations. The results include the reception level curves, mean levels and standard deviation of reception (STD); dynamic path gain (PG) of a specific antenna can be obtained, too, by, e.g., using the presented “offset method.” The results, best applicable for electrically small dipole-like antennas, can be utilized in link budget calculations, channel model development and usability evaluations of different polarization schemes with different on-body links. The effect of the polarization scheme on the mean level is much understood by the theory of radiowave propagation over a lossy ground. Based on this theory, a rough method to estimate the mean reception level (and PG) is introduced and found usable for small dipole antennas under suitable conditions. Finally, reception changes due to uncertain receiver location are studied. A body-normally polarized small dipole receiver is less sensitive to its location than a body-tangential one.