A 2×2 MIMO array antenna is provided which includes two separate radiating elements mounted to an antenna reflector. Each element is linear polarized with two orthogonal polarizations, one polarization excited by a transmit port and the other polarization receiving radiated signals destined for a receive port. The two elements are aligned that the polarizations excited by the transmit ports of the two elements are along a common axis, or the polarizations received by the receive ports of the two elements are along a common axis.