Metal-Only Reflectarray Unit Cell for Dual-Polarization Control

A metal-only reflectarray unit cell to independently control two polarizations is proposed in this paper. The unit cell is based on a nonresonant cross-shaped geometry backed by a metallic plate. Unlike previous metal-only nonresonant unit cell, the metallic arms of the proposed one are not connected to its neighboring unit cells. This fact enables the propagation of the incident wave along the longitudinal direction of the unit cell more specifically, along parallel-plate waveguides formed between unit cells. Depending on the polarization of the impinging wave, the propagation occurs in the waveguides located at vertical or horizontal directions. The simulated results for a designed unit cell at 60GHz show the independent modification of the phase response for one polarization being unaffected the phase response of orthogonal one. Moreover, phase linearity and a phase shift range over 360° are achieved along a operating frequency range with good phase stability under oblique incidence