A method to measure the antenna mode and structural mode for antenna RCS reduction using circulator and phase shifter

An antenna RCS reduction using circulator and phase shifter is one of promising RCS reduction techniques. In this RCS reduction method, the antenna mode scattered field, which is the re-radiated field of antenna, is controlled by the phase shifter to cancel out the structural mode scattered field. In this paper, a method is proposed to measure the amplitude and phase relationship between the antenna mode and structural mode for the deterministic RCS reduction. The effectiveness of the proposed method is verified by experiments using an array antenna with circulators and digital phase shifters.