A dual-band dual-circularly polarized structure reused shared-aperture antenna with high aperture efficiency for satellite communications.

A novel S/Ka dual-band dual-circularly polarized (CP) shared-aperture antenna is proposed in this paper. In the Ka-band, the reflectarray adopts two distinct CP elements, both of which achieve 360° phase shift and linear phase response in the wideband. In the S-band, the radiation array adopts a 4 × 4 units cut-corner square patch to achieve CP performance. Additionally, a steerable beam is achieved through a phase shift feeding network. To effectively improve the antenna aperture utilization and efficiency, the S-band radiator is reused as a part of the Ka-band reflecting ground to realize the aperture-sharing. Experimental results demonstrate that the S-band operating bandwidth covers 2.35–2.7 GHz, achieving a peak gain of 18.6 dBic and an aperture efficiency of 89.2 %. Furthermore, the S-band enables ± 30° beam steering. In the Ka-band, the operating bandwidth covers 28–32 GHz, with a measured 2-dB axial ratio bandwidth is 10.3 %, a peak gain of 37.5 dBic, and an aperture efficiency of 48.1 %. Therefore, a dual-band dual-CP shared-aperture antenna with high aperture efficiency is realized. The antenna offers beam steering in the S-band and wideband capabilities in the Ka-band, making it a valuable candidate for satellite communication systems. [ABSTRACT FROM AUTHOR]