Abstract-Polarization diversity techniques have not received as much attention as others due to the significant difference in mean signal level between copolarized and cross-polarized branches when one polarization is transmitted. However, multiple-input-multiple-output (MIMO) systems where the multipath fading is only partially correlated could use polarization diversity to provide a high diversity gain. Hence there is a need to fully understand the role of true polarization diversity in such systems. In this letter, progressive (true) polarization diversity performance for 3 3 MIMO systems under Rayleigh-fading environments is evaluated through simulations and measurements. True polarization diversity was found to be as significant as spatial diversity at improving diversity gain, and hence MIMO system capacity.

Abstract-Some recent publications have extended the emulating capabilities of reverberation chambers. While polarization imbalance has been removed and Ricean-fading environments are now properly emulated, these chambers are still limited to isotropic nonline of sight (NLOS) scattering. By controlling the power received, number of resolvable multipath components (MPC), angular spread (AS), and angle of arrival (AoA), the emulation of real-propagating environments with both isotropic and nonisotropic scattering are demonstrated in this letter using a reverberation chamber with several multiple-input-multiple-output (MIMO) arrays.

Abstract-MIMO systems where multipath fading is only partially correlated could use polarization diversity to provide a higher diversity gain. Recent letters have proposed the use of tri-polarized antennas and a novel true polarization diversity (TPD) scheme. In this paper, the full potential of TPD is evaluated with both simulations and measurements and compared to conventional orthogonal polarization diversity (OPD). MIMO system performance with respect to capacity and diversity gain is obtained through the use of multimode-stirred chambers for both isotropic and non-isotropic environments. Simulated and measured results in over 591 different MIMO systems show that TPD outperforms conventional OPD for reduced volumes. Likewise, it has been demonstrated that TPD can be effectively combined with spatial diversity to nearly double the diversity gain and MIMO capacity for the same available handset volume.

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Abstract-Several physical parameters of realistic nonisotropic environments have been recently emulated with reverberation chambers. In this letter, the different performance in terms of diversity gain and multiple-input-multiple-output (MIMO) capacity of the same linear MIMO array in different nonisotropic propagating scenarios is demonstrated with a reverberation chamber (RC) for the first time. This could be useful for designing antenna arrays in handset MIMO.Index Terms-Diversity gain, multiple-input-multiple-output (MIMO) capacity, reverberation chamber (RC).