Y.V. Korotetskiy, A.M. Shitikov

Nowadays, because of high interest in mobile radar systems based on phased array antennas, problem of calibration in flight, when it-s no way to gain good anechoic conditions, becomes more and more actual. It implies presence of numerous parasitic signal sources in array aperture, presents results of useful signal re-reflections. Calibration procedure in this conditions leads to distortions in gain pattern, be formed with calibration results. In this paper distortions that appear in radiation pattern of phased array after calibration in presence of parasitic signal in near field ranges are discussed. Two cases of calibration probe alignment are considered. Equations for complex gain pattern calculation for cases of amplitude-phase and phase only handling in presence of parasitic signal in near field range are presented. Asserted, that maximum influence by value on resulted gain pattern makes amplitude-phase handling. Distance effect between parasitic signal together with calibration probe and phased array aperture on gain pattern is discussed. Demonstrated, that maximum distortions takes place when calibration probe and parasitic signal source lays on equal distances from phased array under calibration procedure.