A Wideband High-Efficiency Transmit-Reflect-Array Antenna for Bidirectional Radiations With Distinct Circular Polarizations Based on a Metasurface

In this communication, we present the modeling, design, and experiments of a wideband high-efficiency transmit-reflect-array (TRA) antenna with independent manipulations for transmitted and reflected beams with distinct circular polarizations working in the millimeter-waveband. A polarization-dependent full-space metasurface is designed to transmit the left-handed circularly-polarized (LCP) wave for a transmitarray (TA) operation, and at the same time to reflect the right-handed circularly-polarized (RCP) wave for a reflectarray (RA) operation. The TRA is then optimized with a rectangular shape for a high aperture efficiency (AE) based on a system-level analysis combining the characteristics of a Fermi feed antenna. The experimentally measured results are in good agreement with the simulated ones, achieving a peak gain of 22 dBi (21.5 dBi), a 1 dB gain bandwidth of 18.2% (24.6%), and a 3 dB axial ratio (AR) bandwidth of 38.6% (38.5%) for TA (RA) operation. A total AE as high as 61.2% is realized by comprehensively considering TA and RA operations. The design strategy and the well-performed TRA may find promising applications in wireless and satellite communication systems with bidirectional communication scenarios.