Material Permittivity and Conductivity Estimation From 2 to 260 GHz and Extension of the ITU-R P.2040 Model at Frequency Above 100 GHz

This paper analyzes the frequency-dependent electromagnetic characteristics of usual building materials such as mortar, glass or wood. Reflection and transmission losses are measured from 2 to 260 GHz and the related permittivity and conductivity are estimated. Results are compared with the ITU-R $\mathbf{2 0 4 0 - 0}$ model that is mainly defined for frequency below 100 GHz. As suggested by the ITU model, the permittivity does not depend on the frequency and the conductivity increases with the frequency. However, reflection and transmission losses for frequency above 100 GHz may be strongly impacted by the material inhomogeneity or surface roughness that generates a frequency small-scale fading not predicted by the ITU model.