Calibration system and method for phased array antenna using near-field probe and focused null

摘要

A system and method for calibrating a phase array antenna using a near-field probe and focused null and a signal coherent with the beam received or transmitted at the null location of the probe. In the transmit mode, a base-band phase comparator circuit is established by locating the first probe at the angular location of the null and the first probe measures the field at the null while an offset phase reference probe, or second probe, measures the field at one of the sum peaks of the difference lobes as the reference. In the transmit mode, the method uses the pattern characteristics of the difference pattern to allow direct measurement of the phase reference by the second probe that is located at one of the sum peaks of the difference pattern. In the receive mode, the signal source provides the reference and the second probe is not necessary.