On the Impact of Beam Misalignment in Reconfigurable Intelligent Surface Assisted THz Systems

In this work, the performance of a reconfigurable intelligent surface (RIS) assisted terahertz (THz) (0.1 − 10 THz) wireless system is evaluated in terms of average signal to noise ratio (SNR), ergodic capacity and outage probability. It is assumed that the line-of-sight (LoS) link between the transmitter (TX) and the receiver (RX) is blocked by obstacles laid in the propagation environment. The only way to establish a connection between the transceivers is by employing a RIS, consisting by a large number of electrical conductive elements placed in a rectangular array format. This scenario is examined under different levels of RX beam misalignment, transmission distances, number of RIS reflection units and transmit power levels. The examined performance metrics are extracted by novel and low complexity closed form expressions.