Dielectric rod nanoantenna fed by a planar plasmonic waveguide

This paper presents a tapered dielectric rod antenna excited by a folded dipole coplanar waveguide operating at terahertz frequencies. The effective refractive index of the plasmonic transmission line is obtained by two numerical methods, the Finite Element Method and the Finite-Difference Time-Domain, and it is used to obtain the dimensions of the gap connected to the line. We examine the antenna using two lengths of the rod. For 10 and 5 μm tapered rods, impedance bandwidths of 43.47% and 32.55%, maximum gains of 12.58 and 9.84 dB, and radiation efficiencies of more than 72.09%, and 72.15% are achieved, respectively. The dielectric rod nanoantenna operates at all the optical communication band frequencies: original (O), extended (E), short (S), conventional (C), long (L), and ultra-long (U). The structure of the antenna consists of three layers. The substrate is made of silicon oxide. This paper discusses the effect of using a layer of silicon oxide to prevent direct contact between the silicon rod and the hollow T-shaped silver feedline.