Effect of Water Drops on the Characteristics of a Reconfigurable Intelligent Surface

Reconfigurable intelligent surfaces (RISs) are periodic structures that provide an increase in the bandwidth and coverage area of wireless networks. When deployed in wireless communication systems, such devices are affected by weather conditions, in particular, rain, which may lead to incorrect operation. Amplitude- and phase-frequency responses of RIS and power loss of the signal reflected from RIS are studied versus intensity of rain for RIS cells with a working frequency of 4.8 GHz. For this purpose, an algorithm is proposed to calculate the effect of water drops on the RIS surface on its amplitude- and phase-frequency responses. The results show that the power loss of the signal reflected from the RIS is no greater than 3 dB when the rain intensity is less than 35 mm/h.