Six-port technology for millimeter wave MIMO systems

In this paper, a millimeter wave 2×2 MIMO (Multiple-Input Multiple-Output) six-port based architecture is proposed and analyzed. This line-of-sight MIMO configuration doubles the data rate without increasing channel bandwidth and exploits spatial diversity. In the system analysis, two pseudo-random BPSK signals of 2 Gb/s data rate are transmitted on two MIMO orthogonal channels. The inherent MIMO spatial and additional quadrature diversity (due to six-port interferometry) allows improvements in bit error rate (BER) when the distance changes versus the optimal Rayleigh value. The six-port receivers are modelled in advanced system simulations using on-wafer S-parameter measurements on a fabricated prototype.