Application of the matched THz power meter for material characterization in free space

The paper describes an application of the wide-band THz matched power meter (MPM) for determination complex permittivity of lossy materials in mm and sub-mm range. The measured power transmission coefficient of dielectric slab as a function of incident angle is used for estimating dielectric constant by applying the root-finding procedure to the proper formulated system of the two non-linear equations. Examples of the evaluation the complex dielectric constant of lossy materials are reported at frequency 0.33 THz. The method can also be extended to wider frequency range within 0.1-3 THz.