Reflectarray element combined a tripole with double rings and broadband RCS reduction

This paper proposes a reflectarray antenna element operating in X-band composed of a tripole and double rings. The size of the element is half-wavelength and phase curve is achieved by variation of radius of inner ring from 8 GHz to 12 GHz. This element has 544 degrees of phase range at center frequency. By applying this element to electromagnetic gradient surface using 120 degrees phase difference, the result shows broadband radar cross section reduction in X-band.