On The Design Of Low Sidelobe Reflectarray With Enhanced Bandwidth At Ku-Band

A low sidelobe reflectarray with enhanced bandwidth is designed in this paper. Low sidelobes are achieved by using a logarithmic spiral lattice for placement of unit cells on the reflectarray aperture. The unit cell is made up of a circular ring enclosing a rounded I-shaped dipole, which gives a smooth phase versus frequency response. The size of unit cells is much smaller than lambda(o)/2, which results in a large number of unit cells on the reflectarray aperture and an increased overall efficiency of the reflelctarray. A 665-element reflectarray is designed and simulated, which gives a 1-dB gain bandwidth of 7.5% and -20-dB sidelobe level (SLL) bandwidth of 6.25% with a 60% aperture efficiency at 16 GHz.