N.М. Ushakov, S.Yu. Моlchanov, I.D. Коsobudskii, V.Ya. Podvigalkin

The results of experimental research of thick film dielectric microwave (1-8 GHz) properties of polymer composite materials based on iron oxide, cadmium sulfide, and the mass concentration of 5 to 20 % in the stable volume of low density polyethylene are presented. The samples are polymer thick film 0,08-0,1 mm of thickness , 10 mm length and 7-8 mm width. Composition of the material from which the film was made is consisted of a low density polyethylene in form of a matrix, in which either Fe/Fe₂O₃ or CdS nanoparticles are stabilized. The effective dielectric constant, loss tangent and insertion loss based on of the fabricated samples at frequencies of 1-8 GHz in the asymmetric transmission line are measured. Measurements of the relative effective dielectric constant for samples based on an the iron oxide mass concentration of 5-20 wt. % in 1-8 GHz frequency range indicated that the range of measurable values is rather wide (6-22) for the measured average value in 8-15 range. It is marked that frequency increase leads to dielectric constant reduction for all concentrations of nanoparticles in the matrix. Unlike iron nanoparticles in a matrix of polyethylene semiconducting nanoparticles of cadmium sulfide provide lower effective dielectric constant values. Comparison of measured insertion loss in thick films of polymer-based composite nanomaterial metal nanoparticles (Fe/Fe2O3 + PE) and semiconductor nanoparticles (CdS + PE) showed that the metal nanoparticles are more promising for the development of microwave radar absorbing coatings range comparing to semiconductors. Overall, the levels of insertion loss of the transmission line with thick films based on polymer composite nanomaterials Fe2O3 + PE and CdS+ PE allowed to recommend them as promising for filters with an extended length (a few centimeters). For this, the authors has developed technology of polymer thick film samples production.