Look Through Hygroscopic Indoor Materials at Frequencies from 750 GHz to 1.1 THz

This paper presents the look through losses witnessed for five hygroscopic indoor material groups, namely, brick, leather, plastic, paper, and wood employing the VNA-based Swissto12 MCK terahertz transmission waveguide measurements system. The focus lies on widely encountered materials in the interior of indoor environments. The influence of water footprint on terahertz (THz) wave propagation is studied by foremost measuring the look through losses (i.e., penetration losses) for the chosen materials in dry state then repeated for their wet counterparts in the 0.75 – 1.1 THz frequency range. This paper, however, is the first-ever to investigate the characterization of propagation particularly for hygroscopic indoor materials at THz frequencies. The measurement results reveal an increase in the look through losses for the wet state of the most impacted ingrain wallpaper P1 (rough sample) which is strongly manifested in the 9.44 dB penetration loss difference among its dry and wet states at 925 GHz carrier frequency (f
c
).