Indoor Material Properties Extraction from Scattering Parameters at Frequencies from 750 GHz to 1.1 THz

This paper reports the first ever transmission measurements for a wide choice of different indoor materials such as wood, plastic, paper, brick, glass and leather at frequencies from 750 GHz to 1.1 THz using up-conversion (frequency-domain) method employing Swissto12 system. This commercially available system consists of three parts, namely, vector network analyzer (VNA), the material characterization kit (MCK), and two waveguide extenders which measure the S -parameters in the frequency range of interest to derive the complex dielectric properties of material samples using stepwise Nicolson-Ross-Weir (NRW) method. These frequency dependent material parameters such as permittivity, refractive index and absorption coefficient are mandatory to analyze and model the wave propagation thoroughly for the aforementioned unexplored frequencies along with the ability to classify and localize these different materials precisely. Until previously, only THz time-domain spectroscopy (THz TDS) system based on down-conversion (time-domain) method is employed to measure the spectroscopic responses for this cause.