A 100-GHz Metal-Only Reflectarray for High-Gain Antenna Applications

A 100-GHz metal-only reflectarray antenna is designed, fabricated, and tested. The required phase shift is achieved by simply tuning the metal block height, aiming to eliminate dielectric losses at high frequencies. An equivalent circuit model is employed to analyze the element reflection performance. A prototype reflectarray with a 30-mm square aperture is then fabricated and tested using near-field measurement setup. The measured results show an aperture efficiency of 50.1% at 100 GHz, and the measured radiation patterns agree very well with the full-wave simulation results. To compare the radiation performances, a parabolic reflector, a Fresnel zone plate reflector, and an unwrapped reflectarray of same size are also evaluated. The full-wave simulation results demonstrate that the proposed design not only achieves good radiation performance, but also exhibits advantages such as low profile, easy fabrication, and low cost.