Surveying of Pure and Hybrid Plasmonic Structures Based on Graphene for Terahertz Antenna

Graphene is a unique material for the implementation of terahertz antennas due to extraordinary properties of the resulting devices, such as tunability and compactness. Existing graphene antennas are based on pure plasmonic structures, which are compact but show moderate to high losses. To achieve higher efficiency with low cost, one can apply the theory behind dielectric resonator antennas widely used in millimeter-wave systems. This paper presents the concept of hybridization of surface plasmon and dielectric wave modes. Radiation efficiency, reconfigurability, and miniaturization of antennas built upon this principle are qualitatively discussed and compared with those of pure plasmonic antennas. To this end, a quantitative study of pure and hybrid plasmonic one-dimensional guided-wave structures is performed. The results show that hybrid structures can be employed to design terahertz antennas with high radiation efficiency and gain, moderate miniaturization, and tunability, while terahertz antennas based on pure plasmonic structures can provide high miniaturization and tunability yet with low radiation efficiency and gain.