02208nam a22001817a 4500 NUST 20260207134017.0 621.382,ZAF Zafar, Jamal 131720 Advanced Design and Optimization of Multi-Band Multi-Functional Reflective Metasurfaces for Efficient Linear and Circular Polarization Conversion / Jamal Zafar Rawalpindi, MCS (NUST), 2025 xi, 93 p 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. PhD Electrical Engineering Thesis 133107 PhD EE Thesis 133108 Supervised by Dr. Adil Masood Siddiqui 132783 ddc THE 616122 616122 0 0 ddc 0 0 MCS MCS THE 2026-02-07 0 621.382,ZAF MCSPhD EE-29 2026-02-07 2026-02-07 THE Almirah No.68, Shelf No.6