Bianisotropic Metasurfaces for Optimal Polarization Control: Analysis and Synthesis

Methods to analyze and synthesize two-dimensional, bianisotropic metamaterials (metasurfaces) are presented. First, a general bianisotropic metasurface is analyzed by using closed-form expressions that relate the reflection and transmission coefficients to its constituent surface parameters. Next, a systematic method to synthesize bianisotropic metasurfaces is outlined. It is analytically shown that bianisotropic metasurfaces can be realized by cascading anisotropic, patterned metallic sheets (electric sheet admittances). This geometry allows for straightforward design and fabrication from microwave to optical wavelengths. To demonstrate the utility of the proposed method, four devices exhibiting exotic polarization transformations are presented: a polarization rotator, an asymmetric circular polarizer, an asymmetric linear polarizer, and a symmetric circular polarizer. The optimal performance at centimeter, millimeter, and micrometer wavelengths highlights the versatility of the design process.