Radio channel characterization of intra-body propagation under frequency dispersive perspective

Abstract

In this paper we consider the analysis of the Brillouin precursor formation to understand the impairments undergone by ultra wideband waveforms propagating through naturally dispersive media as human tissues. By means of a frequency-domain method based on considering the frequency response of the medium under study, the effect of these media on the evolution of an input signal can be seen as a frequency filtering. The simulations were performed at a centre frequency of 6.5GHz and for a signal bandwidth of 3GHz. The experienced impairments are assessed in terms of the degradation experienced by the main functions that model the human body radio channel: power delay profile and frequency crosscorrelation function (FCF). For them we analysed the effect of the dispersive propagation in terms of parameters used for information retrieval: peak amplitude decay, CCF secondary sidelobe level and multipath detectability. body radiopropagation. We also review the definition of the parameters adopted to quantify the electromagnetic absorption inside biological tissue under the dispersive perspective.

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“…Instead of the normal exponential decay with distance, the Brillouin precursor pulse follows an algebraic amplitude decay of the peak amplitude. This changes the expected extent and depth of exposure; it does not increase the total amount of energy, but maintains some of it as kinetic energy, redistributes the frequency spectrum of the original signal and carries the energy deeper into the dispersive living tissue of the body than predicted by conventional thermal models [ 17 ]. Wet skin will result in the energy propagating deeper and the amplitude remaining higher [ 18 ].…”