The aim of the research presented in the paper was the establishment of the regularities of change of electromagnetic radiation reflection (S11) and transmission (S21) characteristics values in the frequency range 2.0 – 17.0 GHz of carbon fiber fabric fixed in the polyurethane mastic based matrices depending on these matrixes composition. Such research is urgent due to the following reasons: (1) carbon fiber materials are characterized low stability of S11 and S21 characteristics due to their hydroscopicity; (2) to increase stability of S11 and S21 characteristics and strength of carbon fiber materials it’s necessary to perform their additional processing (for example, to fix them in matrices or substrates). It’s demonstrated in the paper that values of S11 characteristics in the frequency range 2.0 – 17.0 GHz of carbon fiber fabric fixed in the matrix from polyurethane without fillers are from –0.1 till –3.5 dB. S11 characteristic values in the frequency range 2.0 – 17.0 GHz of carbon fiber fabric fixed in the matrix from polyurethane with aluminum oxide, titanium oxide and zinc oxide fillers are from –0.1 till –11.0 dB, from –0.1 till –3.0 dB, from –0.1 till –5.0 dB respectively. S21 characteristic values in the frequency range 2.0 – 17.0  Hz of the listed materials are from –20.0 till –40.0 dB. The studied materials are suitable for use for making special boxes for storing equipment sensitive to microwave interference.