Dual-polarized square-shaped offset-fed reflectarray antenna with high gain and high bandwidth in the 60 GHz domain

This paper presents the design, fabrication, simulation and measurement of a compact dual-polarized, high gain and high bandwidth offset-fed reflectarray antenna operating at 60GHz. The square-shaped reflectarray antenna focusses two wide feed antenna beams with orthogonal linear polarizations into one narrow and dual-polarized main beam. At first, the design procedure is described. This includes the choice of a convenient double-layer unit cell comprising variable-sized crossed dipoles, the aperture efficiency optimization and the transfer of the needed progressive phase distribution to the scattering elements. Next, 3-D full-wave computer simulation results demonstrate the feasibility of the design. Promising nearfield measurement results of a fabricated reflectarray antenna validate the concept and show a high bandwidth of 8GHz and a high gain of more than 33 dBi.