How will antenna polarization affect MIMO and similar technologies in regards to smearing signals and interference?
Most MIMO systems use the same polarization (vertical or horizontal) across all of the antennas used on a particular device. However, it is also possible to use antennas of dissimilar polarization; for example, in a 2 x 2 MIMO system, one of the antennas may be oriented horizontally and the other oriented vertically. In this case, it is possible to avoid situations where correlated multipath causes a drop in throughput for systems using identically polarized antennas; if the antennas have different polarization, then it is difficult or impossible to have a situation where different antennas see correlated multipath signals. However, this is offset by the fact that antennas of dissimilar polarization may pick up signals at widely varying levels; for example, the horizontally polarized antenna might receive signals that are 10-20 dB higher than the vertically polarized antenna. This leads to a drop in throughput because the channel as effectively seen by the antennas becomes Rician, and
