A Single-Layer Broadband Linear-to-Circular Polarization Reflectarray With 45° Offset Feed for Ka-Band Communications

This is the authors' abstract. We don't add key points for this paper.

A millimeter-wave broadband circularly polarized reflectarray with a linearly polarized (LP) source at 45° incidence/reflection based on a single-layer dielectric substrate is introduced. The array element consists of a Jerusalem cross and four straight strips with the end capacitive loading, which provides a 360° phase range and shows a linear phase response in the wide frequency band. When TM and TE polarized waves are incident/reflected at large angles, the additional T-shaped and loop-shaped resonances are generated, respectively, causing the array performance to deteriorate. In this case, the influence of the T-shaped resonance is reduced by arranging elements with phase distortion as far away from the center of the reflectarray surface as possible. Meanwhile, the impact of the loop-shaped one is diminished by choosing the specific phase curve to average the phase compensation discrepancy. Then, the reflectarray with 24 × 24 cells is designed, fabricated, and measured. The measured results have a good agreement with the simulated ones. The measured 1 dB gain and 3 dB axial ratio bandwidths are 13.9% and 28.8%, respectively. The peak gain is 26.22 dBi at 37.5 GHz and the aperture efficiency is 32.1%, which is comparable to that of the excellent LP reflectarray at 45° incidence/reflection.