The active phased array antennas coupled through slotlines

In this paper, a 5-element active phased array antenna coupled through the slotline in the ground plane between oscillators is designed and fabricated. The proposed slotline coupling structure as a novel coupling structure has several advantages over the transmission line coupling such as the expansion capability in two dimensions and distortion free radiation pattern caused by the coupling network. In an experiment, 5-elements active phased array antenna system has 50/spl deg/ scanning range as the free-running frequencies of end elements are controlled.