TY - BOOK AU - Zafar, Jamal AU - Supervised by Dr. Adil Masood Siddiqui TI - Advanced Design and Optimization of Multi-Band Multi-Functional Reflective Metasurfaces for Efficient Linear and Circular Polarization Conversion U1 - 621.382,ZAF PY - 2025/// CY - Rawalpindi PB - MCS (NUST) KW - PhD Electrical Engineering Thesis KW - PhD EE Thesis N1 - 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 ER -