A Single-Layer Wideband Ku-Band Reflectarray for Satellite Applications

This paper presents a wideband, circularly polarized, single-layer reflectarray design, with a bandwidth sufficient to cover both a downlink band from 10.7 - 12.75 GHz and an uplink band from 13.75 - 14.5 GHz. The unit cell is based on a double circular loop that also features an air gap for enhanced bandwidth. The unit cell design is optimized with a group delay-based approach, which is done by optimizing the unit cell geometry and analyzing the impact of the air gap on the linearity of the phase curves. This unit cell design has a phase range of about 500°, thereby minimizing the number of phase wraps required in the reflectarray layout. A circular prototype with a diameter of 11.7λ at 11.725 GHz is fabricated to validate its performance, exhibiting a 1 dB bandwidth of 34% and peak gain of 28 dBi with a clear agreement with simulated results. The reflectarray is intended to be used in satellite applications whereby the downlink and uplink bands are contained within the operating bandwidth of the proposed design.