An imaging system for generating a three dimensional image of tissue of a patient is provided. The imaging system comprises of a transmitter, receiver, antenna system and a display element to form a synthetic aperture radar system that displays a three dimensional view of the tissue. The SAR system has been configured to operate in the near field as opposed to current equipment which can only perform satisfactorily in the far field. A calibration technique has been utilized that allows the system to perform as well as other systems that operate using far field techniques but allows for a much simpler, cost effective system.