Design of an X-band Reflectarray using double circular ring elements

This paper presents a design of an X-band reflectarray consisting of 729 (27×27) double circular ring elements, operating around 10GHz. The elements are printed on an 8mil Rogers 4003 substrate, supported by a 3mm thick polycarbonate and backed by a ground plane. Based on a fixed grid of 15mm (~0.5λ₀), the double circular ring element offers about 600° of relatively slow varying reflection phase variation as a function of their size. The behaviour of the proposed reflectarray is studied both numerically and experimentally. The proposed reflectarray exhibits a peak gain of 28.5 dBi and a 1-dB gain bandwidth of 8%. The reflectarray is fed by a pyramidal horn and an aperture efficiency of 34.12% is obtained after taking into account the 10dB illumination taper and some spillover losses.