An apparatus for facilitating antenna calibration comprising: a directional coupler having first, second, third and fourth ports, the first port selectively connected to a radio transmitter or a radio receiver and the second port connected to an antenna; a power combiner/divider having first, second and third ports; the first port of the power combiner/divider selectively connected to a measurement receiver or a measurement transmitter and the second port of the power combiner/divider connected to the third port of the direction coupler; and a magnitude and phase adjustor connected between the fourth port of the directional coupler and the third port of the power combiner/divider. The magnitude and phase adjustor is configured to be tuned such that any signal input to the second port of the directional coupler results in an output smaller than a predetermined threshold at the first port of the power combiner/divider.