Abstract: A hybrid beam-forming antenna array used in a MU-MIMO communication system, comprising a single digital beam-former connected to M number of passive beam-former sub-arrays and M number of passive beam-former sub-arrays. Each of the passive beam-former sub-arrays comprising a RF transceiver feeding a single RF chain, a 2N-inputs-2N-outputs selection matrix having all its inputs connected to the single RF chain output, and 2N number of antennas each connected to and fed by one of the outputs of the selection matrix. The digital beam-former thereof is feeding each of the RF transceivers of the passive beam-former sub-arrays. The selection matrix thereof has no power-consuming element or external control, and configured to be fed with an RF signal at one or more of its inputs and produce 2N number of separate RF signal beams with progressive phase distribution at its outputs. In addition, the hybrid beam-forming antenna array has no antenna calibration network.