Projecte realitzat en col.laboració amb el centre Helsinki University of Technology

During the last years, the performance of Multiple Input Multiple Output (MIMO) systems has been well established from the theoretical point of view. By introducing a set of multiple antennas in both ends of the link, MIMO systems provide an improvement of channel capacity of wireless systems without increasing the transmission bandwidth. This thesis studies how close to the theoretical optimal performance of MIMO systems one can get with antenna structures when used in realistic propagation environments. In order to do that, Measurement Based Antenna Test Bed (MEBAT), a tool developed by TKK/SMARAD is used. The studied antenna configurations are combinations of reference ideal dipoles. In the first part of the work, a theoretical development of MIMO systems and a definition of the magnitudes used for the study are presented. In the second part of the work, MEBAT and its operating principle are introduced. Next, the considered reference antennas and scenarios for the study of performance are also presented. In the last part of the work the results of the performance study are evaluated and analyzed. As a conclusion, it is possible to point that although MIMO systems provide an improvement of channel capacity, the values achieved in real conditions are not as optimistic as the theoretical ones.