چكيده به لاتين
Nanotechnology is increasingly providing a plethora of new tools to design and manufacture miniaturized devices. On the other hand, Terahertz Band (0.1–10 THz) communication, has envisioned as a key technology to satisfy the increasing demand for higher speed wireless communication. Graphene as a 2-D material with unique electrical, mechanical, and optical properties has already been studied in a multitude of applications such as ultrahigh-speed transistors, nanometric integrated circuits, metamaterials with extraordinary electromagnetic properties, plasmonic devices ( modulators, absorbers, etc), and reconfigurable plasmonic antennas.
First part of this thesis presents analytical and numerical studies of guided-wave structures based on graphene including pure plasmonic structures, hybrid plasmonic structures, and hybrid graphene-metal structures. Based on the results, it is easy to choose an appropriate waveguide as the building block for the guided-wave and radiated-wave applications. In second part of this thesis, three kinds of terahertz antenna are proposed. First, waveguide-fed terahertz antennas based on hybrid graphene-metal structure with the goal of achieving to frequency tunability compared with metallic terahertz antennas. Second, dipole-like antennas using few-layer graphene fed by photoconductive sources are proposed to achieve a better trade-off between miniaturization and radiation efficiency than current monolayer graphene antennas. Third, THz dielectric resonator antenna coupled to graphene plasmonic dipole is introduced as an efficient way to enhance the gain of terahertz antennas without occupying a large area.
