A wideband folded reflectarray using single-layered sub-wavelength elements

This paper presents a design of wideband folded reflectarray using single-layered sub-wavelength elements. Different to existing folded reflectarray designs where a half or near half wavelength unit cell is adopted for lower reflectors, this work uses rectangular patch elements arranged in a sub-wavelength grid on a single layer of substrate, in an effort to achieve wide bandwidth of folded reflectarrays. The proposed folded reflectarray exhibits a broadband performance with a low-profile structure. The measured results show that the folded reflectarray with 0.3λ grid spacing can achieve a 1-dB gain bandwidth of 16% with an aperture efficiency of 44%.