Characterization of the ultra-wide band channel

Ultra wide band (UWB) is an emerging wireless technology. It is referred to as baseband, impulse or carrier-free, and it has been proposed for unlicensed operations over bandwidth spanning several GHz, provided the power spectral density of transmitted signals are adherent to some emission masks. From these considerations, it follows that UWB channels are frequency selective even if the channel consists of only a single path, thus significantly altering the shape of the transmitted pulse. In this paper, the authors intend to investigate about the frequency selective effects of common building materials in the frequency band where UWB systems are allowed to operate 3.1-10.6 GHz, thus deriving an UWB channel model composed by a cascade of two linear systems that accounts for the multipath propagation and pulse distortion. The motivation of this work is that the analysis of the filtering effects of the transmission through common building materials is a quite unexplored aspect in the context of ultra wide-band communications. The purpose of this paper is to consider the bandwidth ranging from 1 GHz to 18 GHz. The analysis has been performed both in time and frequency domain, using respectively a commercial available UWB transceiver and a network analyzer. The channel impulse and frequency responses have been analyzed in order to compare the obtained results and find a correspondence between them.