Broadband Linear to Circular and Multi-Band Cross Polarization Conversion Reflective Metasurface for Ku, K and Ka Band Applications

This work proposes a low-profile reflective meta-structure to convert incident linearly polarized (LP) waves to circularly polarized (CP) waves with broadband characteristics and also into cross polarized waves with narrowband characteristics. The unit cell in the proposed design consists of a tapered rectangular metal strip along the diagonal and a square patch at the center. When an X-polarized or Y-polarized wave impinges on the meta-structure, it converts into circular polarization in Ku, K and lower portion of spectrum in the Ka-band. This meta-atom exhibits cross polarization conversion from 10.98-12.15 GHz, 31.62-34.26 GHz and 34.95-37.2 GHz. The dimensions of the optimized unit cell are $0.292 \times 0.292 \times 0.062$ $\lambda_{0}{ }^{3} \mathrm{~mm}$ (where $\lambda_{0}$ is calculated based on lowest operating frequency) with axial ratio bandwidth 77.76% can be used for the future wireless communication, also when the actual and mirror meta-atom arranged in checkerboard format can be used for RCS reduction application.