On the Path Loss Characteristics of Sub-6 GHz 6G Indoor Channels Enabled With Coded Metasurface Based Anomalous Reflectors

We investigate the effect of reconfigurable intelligent surfaces (RIS) on the path loss of sub-6 GHz indoor channels using measurement studies. We experimented on NLOS indoor channels enabled by a coded metasurface based anomalous reflector which steers an incident EM radiation from θi = 0° to a reflected angle θr = 30° in the band 5.850 − 6.000 GHz. We carry out measurement of path loss (−|S21|) in the band 5 − 9 GHz for a range of distances using VNA and critically examine the pathloss in the in-band and out-of-band frequencies of the RIS. We compare the path-loss performance for the same setup using a metal plate of equal aperture area. Experimental results indicate that the RIS reduced the pathloss by least 25 dB around strategic locations more than metal reflector. This research is invaluable for the future RIS-based 6G wireless networks for coverage prediction, link-budget calculation, and capacity evaluation.