The paper presents the results of studying electromagnetic response from polymer composite materials in the frequency range from 0.1 THz to 1.6 THz obtained using a BWObased spectrometer and a time-domain spectrometer. The composites used were epoxy resin with the addition of barium titanate (BaTiO3) with a mass concentration of 40% to 80%. Based on these data, the values of the complex permittivity of composite samples are calculated and analyzed, and the electromagnetic response from the samples is modeled. An assessment of the applicability of this material in the elements of the THz range technology is carried out.