Metasurface Design for Polarization Conversion Applications

Abstract

Metasurfaces offer extraordinary chances to manipulate and control the phase, amplitude and polarization of EM waves. From the time when the sub-wavelength unit cell of the metasurface can be designed to achieve any desired functionality, as a result, they have found several usage in various applications like flat lensing, real-time holograms, antennas gain enhancement, beam splitting, radar cross section reduction, and polarization conversion. Due to its key job in several applications, polarization manipulation has always been of vital importance to scientific and engineering community. Nevertheless, polarization manipulation can be attained through conventional methods, for instance by impinging a wave through an anisotropic material where the phase difference is provided as the wave propagates through the material or Faraday Effect, nevertheless, these methods required bulky size and have narrow bandwidth when the operating wavelength is much larger. So as to attain polarization manipulation through compact design, scholars have stimulated their motivation towards meatasurfaces. In this concern, polarization rotators and beam splitters have been proposed in literature for microwave regime in reflection and transmission mode, but most of the structures are either angular stable or restricted to single operation. In this thesis, a c-shaped anisotropic metasurface is proposed to obtain multiple operations for both reflection and transmission mode. The reported metasurface has ability to obtain circular and cross polarization conversion of the incident electric field for reflection mode in microwave frequency regime. The same design is optimized by using ultrathin flexible substrate to achieve half-mirror and quarter-wave plate operation in a transmission mode. Moreover, proposed metasurface show a stable response against oblique incidence angle when related with recent metasurface based polarizers and beam splitters for all operations. This metasurface not merely offers multiband operations, high efficiency but also supports in miniaturization and overcome the requirement of various components in the system. The angular stability, compact size and multiple functionalities make it a strong applicant for applications functioning in C, X and Ku bands.