A wideband multi-bit reflectarray antenna with low cross-polarization based on nonradiative dielectric waveguide

This paper presents a wideband reflectarray antenna (RA) based on a nonradiative dielectric (NRD) waveguide with an inserted metal blade for muti-bit phase quantization. The proposed design eliminates the need of resonant components that typically exist in traditional RAs. Additionally, low cross -polarization is achieved by exciting the appropriate propagation mode in NRD waveguide. The beam scanning performance based on multibit phase quantization is verified by a series of static prototypes. Compared to traditional rectangular waveguide RAs, the proposed design possesses collimated beam scanning up to 60 degrees without grating lobes, due to the compact unit cell dimensions. At a collimation beam angle of 20 degrees , a 1 -dB gain bandwidth of 18 % is achieved with an aperture efficiency of over 40 % and a cross -polarization level of below -40 dB.