A full-duplex 2x2 multiple-input multiple-output, MIMO, antenna array comprising: an antenna reflector defining an x-y plane; a first antenna element mounted on the antenna reflector having a first linear polarization element oriented in a first direction and a second linear polarization element oriented in a second direction orthogonal to the first direction; a second antenna element mounted on the antenna reflector having a linear polarization element collinear to the first direction; a third antenna element mounted on the antenna reflector having a linear polarization element collinear to the second direction; and a fourth antenna element mounted on the antenna reflector in proximity with the first antenna element and having a first linear polarization element parallel to the first direction and a second linear polarization element parallel to the second direction; wherein the first linear polarization element of the first antenna element and the first linear polarization element of the fourth antenna element are coupled to a first port; the second linear polarization element of the first antenna element and the second linear polarization element of the fourth antenna element are coupled to a second port; the linear polarization element of the second antenna element is coupled to a third port; and the linear polarization element of the third antenna element is coupled to a fourth port; wherein the first port is coupled to transmitter input A, the second port is coupled to transmitter input B, the third port is coupled to receiver output A, and the fourth port is coupled to receiver output B; or wherein the first port is coupled to receiver output A, the second port is coupled to receiver output B, the third port is coupled to transmitter input A, and the fourth port is coupled to transmitter input B. an antenna reflector defining an x-y plane; a first antenna element mounted on the antenna reflector having a first linear polarization element oriented in a first direction and a second linear polarization element oriented in a second direction orthogonal to the first direction; a second antenna element mounted on the antenna reflector having a linear polarization element collinear to the first direction; a third antenna element mounted on the antenna reflector having a linear polarization element collinear to the second direction; and a fourth antenna element mounted on the antenna reflector in proximity with the first antenna element and having a first linear polarization element parallel to the first direction and a second linear polarization element parallel to the second direction; wherein the first linear polarization element of the first antenna element and the first linear polarization element of the fourth antenna element are coupled to a first port; the second linear polarization element of the first antenna element and the second linear polarization element of the fourth antenna element are coupled to a second port; the linear polarization element of the second antenna element is coupled to a third port; and the linear polarization element of the third antenna element is coupled to a fourth port; wherein the first port is coupled to transmitter input A, the second port is coupled to transmitter input B, the third port is coupled to receiver output A, and the fourth port is coupled to receiver output B; or wherein the first port is coupled to receiver output A, the second port is coupled to receiver output B, the third port is coupled to transmitter input A, and the fourth port is coupled to transmitter input B.