Study of Terahertz Antenna by Surface Wave Theory

In this paper, current pulse that propagates in Terahertz antenna was simulated as a propagated surface wave. The surface wave modes which propagate in electrode were studied. It was found that the current pulse propagates as a bulk electromagnetic wave in the antenna gap and that the current pulse propagates as a surface wave in the electrodes. Phase velocity and loss of each mode were investigated. The relation between thickness of the antenna electrode and optical properties of the substrate, such as absorption and refraction index, with surface wave characteristics was studied. After solving surface wave equation for the three-layer structure, dielectric-metal-dielectric, it was found that two surface wave modes, slow mode and fast mode are allowed to propagate in the electrode layer and that surface wave cannot propagate in the antenna gap region.