Directional indoor ultra wideband propagation mechanisms

The paper describes a characterization of the influence of the antenna and of the radio environment on ultra wideband (UWB) propagation mechanisms. The purpose of the study is to combine theoretical analysis, computer simulations and practical experiments to have both a time and a frequency approach to the phenomena involved. A channel sounding setup (based on a network analyzer and almost constant gain antennas) with a time resolution of 350 ps and a bandwidth of 2.9 GHz was designed. We point out some of the interesting properties of the UWB channel, such as a robustness to multipath fading, small losses due to propagation through different obstructions and possible interesting localization properties. Moreover, the standard double differentiation behavior of the antennas was not found in experiments. Indeed, signal distortion effects are highly dependant on actual antennas used and should therefore be included in the total system design.