A High-Efficiency Single-Layer Reflectarray for Millimeter-Wave Applications

This paper presents a single-layer reflectarray (RA) with a high aperture efficiency for millimeter-wave applications. The RA is composed of 400 unit cells, and every unit cell is constructed with center-connected crossed dipoles and a ground printed on the other side of a single-layer substrate. By introducing two degrees of freedom to control the phase, a phase shift of 360° is obtained. This offset-fed RA is designed, fabricated, and tested. The maximum peak gain of 27.1 dBi at 30.8 GHz with an aperture efficiency of 55% are achieved. The measured 1-dB gain bandwidth is 16.5% (29.5 GHz - 34.8 GHz).