Research Projects

The future of 6G wireless systems and mobile networks requires higher capacity and improved transmission efficiency. The transmission capacity is determined by three factors: transmission bandwidth, modulation order, and multiplexing. Modulation order has reached a practical limit, and system bandwidth scarcity is already present. To increase the multiplexing order, an emerging OAM multiplexing scheme in the microwave domain is proposed. The proposed system involves a high directive beam focusing antenna system with circular polarization, which requires intelligent manipulation of EM waves' amplitude, phase, and polarization states. Artificial materials, such as meta-materials and metasurfaces, can be used to perform wave manipulations. Metasurfaces, a 2D equivalent of bulk metamaterials, can overcome fabrication challenges with negligible losses. By meticulously modeling the amplitude and phase response of meta-atoms through the unit cell structure design, it is possible to control EM waves upon incident on these metasurfaces effectively. Properly tailoring the phase profile in a metasurface can modulate wavefronts in transmissive, reflective, and bi-functional modes. The project's novelty is the use of photonic topological insulators (PTI) in designing metasurfaces, which exhibit unique EM characteristics and are highly reliable. The project also aims to generate vortex beams with robust and higher order modes by combining the features of gradient metasurface and Chern photonic topological insulators.