Bandwidth enhancement element for linearly polarized reflectarray design in Ku-band

A Ku-band 14×14 center-fed linear polarized wideband reflectarray antenna is presented in this paper. A new element, which can reach up to a bandwidth of 33.3%, from 13 GHz-18 GHz, is proposed to extend the bandwidth of the reflectarray. The proposed element consists of a square loop and four folded stubs inside, which is modified from the conventional single-loop element. The sub-wavelength technology is applied to enhance the aperture efficiency. The simulation results show that the 1-dB gain bandwidth is 36.7%, and the bandwidth for aperture efficiency larger than 50% can reach up to 36%. The maximum efficiency is 67.6% occurring at the center frequency of 15 GHz.