  This paper focuses on MIMO Power Line Communication (PLC) to provide
increased performance. In MIMO PLC, appropriate coupling methods are necessary
in order to enable the effective injection of the signal through the broad band
PLC channel so that high data rates can be achieved. In this paper, we want to
analytically characterize strengths and weaknesses of each coupler design
(topology) from an electrical circuit perspective. We dwell on the description
and analysis of the three main and common configurations used for the MIMO
couplers: star (S), triangle ($\Delta$) and T.
