SPECTRAL MEASUREMENTS OF DIELECTRIC PROPERTIES OF POLYPROPYLENE FILMS IN THE SUBTERAHERTZ FREQUENCY RANGE

Read more We describe three alternative quasi-optical methods for measuring dielectric properties of low-absorbing polymeric films at subterahertz frequencies using BWO-spectroscopy. For two of them, the dielectric permittivity of a pure film is determined through amplitude-phase measurements when the film is inserted into Mach-Zehnder and Fabry-Perot interferometers. In the third case, the permittivity is retrieved via investigating spectral features of a supplementary resonant metallic structure created on the film’s surface to enhance its dispersive properties. The described methods were applied to measure the dielectric permittivity for polypropylene films of different thickness (from 10 to 512 um) from the GoodFellow company (UK). The experimental data obtained by these three techniques are compared with each other and the analysis of factors explaining discrepancy in the measured values of the dielectric permittivity is presented.

Keywords:
material characterization, BWO-spectroscopy, interferometry, subterahertz, polymeric films, frequencyselective surface
УДК 537.86.029.65/.79, 543.45

SPECTRAL MEASUREMENTS OF DIELECTRIC PROPERTIES OF POLYPROPYLENE FILMS IN THE SUBTERAHERTZ FREQUENCY RANGE