A wireless communication system can include polarization agile antennas to enable adaptation to the polarization characteristics of a changing propagation channel. In one embodiment, a mobile terminal can include one or more polarization-agile antennas, and can select polarization orientations that are preferentially propagated through the changing propagation channel. In another embodiment, a mobile terminal having two polarization-agile antennas can provide spatial diversity, polarization diversity, or combinations of both. Multiple-input multiple-output (MIMO) systems can include polarization-agile antennas to allow for switching between spatial and polarization diversity, combined spatial and polarization diversity, and various Eigen channel decompositions using spatial, polarization, and combined spatial and polarization dimensions. An extended polar normalization provides enhanced fidelity for methods of communications system modeling.