On the Design of Unit Cells with Diagonal Symmetry for Wideband Polarization Converters

This paper presents a theoretical study of diagonal-symmetric metasurfaces based on very simple transmission-line models in order to achieve wideband polarization converters. The approach profits from the decomposition of the incident-field vector in field components directed along the diagonal-axis, decoupling the problem into two different, individual and independent subproblems. This issue reduces considerably the complexity of the problem, and allows for a better understanding of the physical insight of the structures. Practical examples of wideband rotators/circular polarizers based on very simple metasurface-cells are implemented with the aim of supporting the theoretical conclusions. Experimental prototypes have suc-cessfully been manufactured and will soon be tested.