Generalized Diversity Gain of a Mobile Antenna

Usage modes of a handset device typically involve incidental random motion, rotation and blocking through interaction between the receiver antenna and the operator's RF absorbing body. These are known to generate variability in antenna response. It is counterintuitive that such random variations in antenna response can result in diversity gain of practical applicability. However it is shown herein that this diversity gain occurs.;An antenna diversity system based on merging polarization and spatial diversities applicable to handheld terminals is developed. The proposed technique is based on the motions of a dual polarized antenna and is effective in enhancing the initial signal acquisition in severe multipath environments. The realizable diversity gain is quantified through comparing the performance of the proposed technique with that of previous work from a theoretical and experimental perspective, the experimental part being conducted with GPS signals.;The combined spatial-polarization correlation formulation for a multipath environment based on the uniform sphere of scatters model is developed. The closed form expressions developed are useful for quantifying the potential diversity gain in antenna diversity systems. The theoretical results are verified through an extensive set of measurements.;A diversity gain generating technique based on incidental random antenna motion and rotation is proposed. This diversity gain is quantified from a theoretical perspective and verified through measurements carried out at 1947.5 MHz.;A diversity gain generating technique based on random variations in antenna blocking is proposed. The diversity gain can be exploited to enhance signal detectability of handheld receivers in indoor multipath environments. This diversity gain is quantified from a theoretical point of view and measurements carried out at 1947.5 MHz verify these theoretical predictions.;Traditional methods of quantifying diversity gain are based on several factors among them receiver processing (e.g. combining algorithms) and target performance requirements (e.g. bit error rate) and therefore are very specific to the overall system. A more general measure of diversity gain that excludes receiver processing and is independent of target performance requirements is proposed. This metric is utilized to evaluate the generalized diversity performance of a small antenna with motion, rotation and blocking relative to a stationary antenna.