In this study we analyze how to optimize antenna diversity system on small handset design. The evolution of the use of the mobile phone with a constant need for higher capacity on small device has raised new challenges in the handset and antennas design. Our main objective is to investigate different parameters affecting the overall efficiency of an antenna system on a small handset. In fact today customers can use their phones in data mode not only to send messages but also to download data or watch video in streaming for example. This development has induced new ways to use and hold the phone. The different user’s interactions can in some cases strongly impact the efficiency of the overall system. This is why we will study the influence of the user on antenna parameters like correlation, mean effective gain, branch power ratio, power received and channel capacity variations.
Our analysis and conclusions are based on simulations results and also on results coming from measurements campaign done from Aalborg University in downtown Aalborg in 2011. We have proceed by first extracting the data then clustering it by groups parameters, computing statistical analysis, and analyzing the impact of each of them on the overall antenna design.
Based on the results in the simulation part we have observed for the two handsets studied that the user decreases the correlation, the mean effective gain and the power received in θ polarizations in each channel models considered (TAGA, AAU and Isotropic). In the measurements’ analysis we have analyzed parameters variations of ten handsets with different antennas design in eight common use cases that an user may experience plus a study of the SAM and hand phantom performance. We have noticed a confirmation of the negative impact of high correlation on the MIMO capacity performance. We also characterized which antenna design is more sensitive to reach such high correlation. Moreover the branch power ratio impact on the channel capacity performance is limited. In a further work different level of signal to noise ratio and different antenna combining techniques should be experienced.