Channel Measurements for Indoor and Outdoor Reconfigurable Intelligent Surface (RIS)-assisted Links at 3.5 GHz

This paper explores a far-field RIS-assisted communication environment operating at 3.5 GHz. A comprehensive channel measurement campaign is conducted in both indoor and outdoor settings, covering scenarios with the RIS activated and deactivated, using both directional and omnidirectional antenna configurations. The results show that activating the RIS flattens the channel response and reduces frequency selectivity in both indoor and outdoor environments. Additionally, with directional antennas, the received power levels are a few dB higher in both the RIS-on and RIS-off cases compared to using omnidirectional receive antennas.