Effect of mutual coupling and human body on MIMO performances

In the last recent years, MIMO (Multiple-Input Multiple-Output) system have been studied and developed by many researchers. These systems allow an increase in the binary data rate and the improvement of the quality of received signals, due to spatial multiplexing and space-time diversity. The performances of MIMO systems depend on the antenna design. In this paper, we focused on the importance of mutual coupling and human effect on the MIMO performances. Three different types of antennas have been designed: monopoles, cross-polarized dipoles and a planar inverted-F antennas (PIFAs). The antennas work at 2.45 GHz for WLAN applications and also PIFAs work at GSM 1800 and 5.4 GHz for the other WLAN band. The results show the importance of spacing among radiating elements due to the mutual coupling and measurements in a reverberation chamber comparing the effect of the user´s head.