Design of Single-Layered Ultrawideband High-Efficiency Circularly Polarized Reflectarray

In this letter, we present a single-layered circularly polarized reflectarray antenna with a broad operating bandwidth in terms of realized gain, axial ratio (AR), radiation pattern, and aperture efficiency (AE). By employing multiple plasmon resonances, the proposed quasi-I-shaped element achieves a broadband linearly polarized conversion effect, which will contribute to a broadband reflectarray design. Thus, based on the element angular rotation method, a broadband offset-fed reflectarray with size of 215 × 215 mm 2 and cells of 43 × 43 is designed, simulated, and then fabricated and measured. Good performances can be observed from both simulated and measured results, which confirm that the reflectarray antenna achieves a 75% 3 dB AR bandwidth (10-22 GHz) and a 49.7% 3 dB gain bandwidth (12.4-20.6 GHz). Furthermore, the measured AE exceeds 50% within a 28.2% bandwidth.