Ultra wideband signal propagation in desktop environments

Although ultra wideband (UWB) propagation in indoor environments has been intensively studied, there have, as far we know, been no published studies of UWB propagation in desktop environments, where wireless personal area networks are expected to be most commonly employed. Short-range propagation measurements were carried out using UWB and continuous wave (CW) signals on a rectangular metal plate simulating typical desks with and without a low vertical metal partition panels. The frequency of the UWB signal spanned from 3.1 to 10.6 GHz and that of the CW signal was 6.85 GHz. A vector network analyzer and two omnidirectional UWB antennas were used to obtain frequency-domain response of the propagation paths. With the partition panel, the CW reception level showed approximately a 36-dB spatial variation, induced by the interference between the direct and the reflected waves, but the UWB reception level had no particular plunges. We also measured the additional losses when the propagation paths were blocked with a human arm and when the antenna was covered with a human palm. These losses were found to be 10 to 12 dB caused by an arm; and 6 to 7 dB caused by a palm.