On the performance of adaptive MIMO systems using radiation pattern recongurable antennas

In the last few years, multiple input multiple output (MIMO) have been suggested as an effective mean to enhance transmission performances by exploiting multipath scattering effects. These systems use multiple antennas at both receiver and transmitter in order to increase communication capacity. Theoretically, the higher the number of antennas, the better the capacity enhancement. However, their radiation characteristics have also an important impact on the channel capacity. Antenna patterns which offer low signal correlation between each radiating element are suitable for a high channel capacity. Furthermore, since the channel is not stationary, it is interesting that each antenna of the MIMO system can switch between different radiation pattern configurations in order to optimize in real time the channel capacity to prevent environment modifications. So reconfigurable antennas used as one of multiple radiating elements offer an additional degree of freedom for adaptive MIMO communications.