Ku-band broadband reflectarray antenna with slot rings on patch and ground elements

A reflectarray antenna (RA) with 20 χ 20 elements is presented. A detailed design procedure was introduced, aiming at wider gain band-width and higher aperture efficiency. The element, designed at Ku-band, using a simple ring on patch and a slot on ground has two layers. This structure can generate multi-resonant to achieve broad bandwidth. The impact of the feed location was discussed, and then the feed position was optimized to improve the antenna aperture efficiency. Furthermore, the large RA was calculated and simulated. The radiation patterns and antenna gain simulated by full-wave software(CST) were in good agreement with those calculated with definition equations. The -1 dB gain relative bandwidth of the designed RA is 16% and aperture efficiency is 46.2% at 12.5 GHz.