A Single-Layer High-Efficiency Wideband Reflectarray Using Hybrid Design Approach

A Ku-band single-layer reflectarray (RA) antenna with high aperture efficiency in a wide frequency band is proposed. The reflectarray element is composed of double square loops and an inner square patch, which operates at two different phasing modes by properly adjusting its geometrical parameters. A hybrid design approach, which combines four commonly used wideband RA design approaches-namely, the subwavelength spacing, multiresonance structures on an electrically thick layer, multitype elements, and the dual-frequency phase synthesis-is adopted to achieve the high-efficiency wideband performance. An offset RA prototype with a 400-mm circular aperture is designed, fabricated, and tested. The measured aperture efficiency is over 60% within the frequency band of interest (12.0-14.9 GHz, 21.6%), and the bandwidth of aperture efficiency over 40% is 29.0%. Well-defined measured radiation patterns within the frequency band of 11.5-15.5 GHz are also obtained, which further validate the excellent radiation performance of the proposed RA design.