Wideband Metal-Only Reflectarray Using Polarization Conversion Element for X-/Ku-Band

Abstract

A wideband polarization conversion element based metal-only reflectarray is proposed for X- and Ku-band application. The unit cell (bit 0) and its mirror-like symmetry (bit 1) are used as 1-bit phase shifters to cover 360° phase of the reflectarray. 0°/180° quantized phase shift is used in the frequency range of 9 GHz-14 GHz. The unit cell consists of a bowtie-shaped slot-loaded metal patch with a thickness of 0.2 mm on the top surface. It is backed by a metallic ground plane at the bottom, with a 5 mm air spacer separating the metal patch from the ground plane. The unit cell is designed to exhibit wideband characteristics by employing the polarization conversion technique, a novel approach for enhancing bandwidth. The reflectarray measures 260 mm in diameter and features a focal length of 150 mm, fed by a pyramidal horn antenna. The reflect array achieves a peak gain of 24 dBi, with an aperture efficiency of 22 % at 11 GHz. Additionally, it features 3-dB gain bandwidth of 40% (9.3 GHz-13.8 GHz), highlighting its capability for satellite communication. © 2024 IEEE.