Reciprocal Optimized Surface Impedance Multiple Angle Retro-Reflective Metasurfaces

In this paper, we introduce a reciprocal multiple angle retro-reflective metasurface following the general principles of the surface impedance concept and numerical optimization of the super-cell design. The aim is to obtain retroreflection simultaneously at the desired direction and open channels of the designed metasurface. With an increase of periodicity of the super-cell design, the number of open channels increases according to Floquet-BLoch analysis. With an increase up to $\mathbf{2}\lambda$ and higher the system is said to become very lossy and loses its reciprocity in the symmetrical directions. In this particular case, a new design super-cell approach for a reciprocal retrodirective metasurface is studied for a periodicity of $\mathbf{2.9}\lambda$ at a 10° incident angle. For the validation of the analysis and performance of the designed metasurface, the monostatic RCS is given to determine the performance of the metasurface for retro-reflection. The results show significant levels at the desired angle (10°) and open channels (−32° and −44°), as well as a recovery of the loss in the symmetrical directions (−10°, 32° and 44°) using the reciprocal metasurface design approach.