NUST Institutions Library Catalogue

Metasurfaces, engineered with subwavelength structures, have transformed electromagnetic
wave manipulation by offering unprecedented control over polarization, phase,
and amplitude, enabling compact and efficient structures for modern wireless communication
systems. However, existing designs suffer from narrow bandwidth, limited
functionality, and fabrication complexity. This thesis presents novel multi-band reflective
metasurfaces for efficient linear and circular polarization conversion, addressing
these challenges. The proposed metasurfaces are designed using a unit cell approach,
optimized through full-wave electromagnetic simulations, and verified experimentally
in the X, Ku, K, Ka and U bands. The structures incorporates asymmetric resonators
to achieve wideband operation with high efficiency. Results demonstrate an average
polarization conversion efficiency exceeding 90% at oblique incidence angles up to 45°
across the targeted bands, outperforming state-of-the-art designs. The metasurface
achieves wideband operation while maintaining compactness. Experimental validation
confirms excellent agreement with simulation results. The work complements prior
advancements in polarization conversion, which can be extended to active wave manipulation
through reconfigurable reflective metasurfaces, paving the way for innovative
approaches in adaptive beamforming and dynamic polarization control. Overall, this
work advances the field of metasurfaces, with potential applications in satellite communications,
radar, and next-generation wireless networks.