Design and Validation of a Metallic Reflectarray for Communications at True Terahertz Frequencies

Wireless communications in the terahertz (THz) band (0.1-10 THz) is a promising and key wireless technology enabling ultra-high data rate communication over multi-gigahertz-wide bandwidths, thus fulfilling the demand for denser networks. The complex propagation environment at such high frequencies introduces several challenges, such as high spreading and molecular absorption losses. As such, intelligent reflecting surfaces (IRSs) have been proposed as a promising solution to enable communication in the presence of blockage or to aid a resource-limited quasi-omnidirectional transmitter direct its radiated power. In this paper, we present a metallic reflectarray design achieving static controlled non-specular reflection at true THz frequencies (i.e., 1-1.05 THz). We conduct extensive experiments to further characterize and validate its working principle using terahertz time-domain spectroscopy (THz-TDS) and demonstrate its effectiveness with information-carrying signals using a continuous wave (CW) THz testbed. Our results show that the reflectarray can help facilitate robust communication links over non-specular paths and improve the reliability of THz communications, thereby unleashing the true potential of the THz band.