Pattern diversity with multi-mode circular patch antennas in clustered MIMO channels

The throughput that a MIMO channel can support is a function of different array parameters. Another technique, for miniaturized antenna designs, is polarization/pattern diversity where the antennas are designed to radiate with orthogonal radiation patterns and polarizations as a means to create uncorrelated channels across different array elements. The benefits of pattern diversity have been shown by L. Dong et al. (2003). That analysis, however, did not use realistic channel models. We aim to extend the analysis of Dong et al. to clustered channel models, adopted by the IEEE 802.11n standard body for wireless local area networks (WLANs). We analyze MIMO arrays consisting of circular microstrip antennas to enable pattern diversity and compare their performance against conventional uniform linear arrays. We also model the effect of mutual coupling and measure the performance degradation produced by the near-field effects. We briefly review the channel model and the properties of circular microstrip antennas. Then, we analytically compute the spatial correlation coefficients and evaluate the MIMO channel capacity. Pattern diversity yields better performance than space diversity.