An accurate mid-field calibration technique for large phased array antenna

Large APAA (active phased array antenna) contains hundreds of elements and the electrically beam-steering performance of an APAA mainly depends on the amplitude and phase distribution of each active element. The amplitude and phase distribution is set up via controlling the attenuator and phase-shifter in each element module. Therefore, an ideal initial amplitude and phase excitations for array elements must be acquired in APAA factory development stages. In this paper, a fast and accurate measurements and calibration technique for APAA's active elements is presented. The technique takes the advantages of array antenna mid-field measurements and elements phase-rotating calibration methods. The well-behaved antenna pattern test results shown in this paper match the requirements of amplitude and phase measurement accuracy for APAA initial amplitude and phase excitations.