UWB polarization measurements in multipath channels

Ultra-wideband (UWB) radio systems have attracted considerable attention as a candidate for wireless personal area network (WPAN) applications. In order to evaluate the performance of UWB radio systems, a radio link budget calculation is necessary for real channels. An important part in the link budget calculation is related to the effect between the receiving antenna and the electric-field wave polarization impinging on the receiving antenna, for example, the variance on a received signal waveform or a received energy with respect to receiving antenna orientations. To characterize the polarization effect at the receiver, it is useful to establish the way to measure UWB wave polarization in real channels.; In this thesis, UWB polarization measurements in indoor multipath channels are studied for a transmitted UWB impulse signal. To investigate the polarization effect, we propose a UWB multipath channel model with a Hertzian dipole antenna approximation. Based on the channel model, a wave polarization estimation process is proposed and tested on multipath signal waveforms. Waveforms were measured for three orthogonal receiving antenna orientations to reflect polarization sensitivity. The fidelity of the estimation process is verified by comparison between the measured and estimated signal waveforms for a reoriented receiving antenna.; With the polarization estimate, analytic received signal energy bounds with respect to receiving antenna orientations are provided in closed form, and the corresponding optimal receiving antenna orientation is characterized for the maximum received energy. For each of the measured channels, the empirical received signal energy distribution is plotted for all possible receiving antenna orientations, and empirical received signal energy bounds are discussed for measured channels.