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Simple and correct formulas are derived for calculation of an effective isotropic dielectric constant, which characterizes the wave propagation in microstrip lines on anisotropic substrates made of r-cut sapphire crystals. The r-plane is extensively used for epitaxial growth of high-T, superconductor YBa,Cu,O, films as applied to microwave integrated circuits. In contradistinction to previous models developed for z-cut sapphire, the nondiagonal dielectric permittivity tensor of r-cut sapphire is used. The effective dielectric constant of a microstrip line on r-cut sapphire substrate is found as a function of the strip-line geometry and the orientation of the crystallographic axes with respect to the symmetry plane of the microstrip line.

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Polymer coatings on the basis of the biphenol Novolac potting epoxy compound with a 65% content of spherical particles of fused quartz as a filler were studied by the method of dielectric spectroscopy in a wide frequency range. Dielectric measurements were performed in frequency and temperature ranges of (10 -2 to 5 × 10 9 ) Hz and 20 to 200°C, respectively, on film samples of composite coatings formed on different sub strates. It was shown that the application of dielectric spectroscopy allows one to study the effect of the degree of the adhesion interaction with the substrate on the processes of structuring in the epoxy polymer matrix and to investigate the degradation processes in the coatings under the effect of high temperature and relative humidity. It was also shown that the values of the glass transition temperature (T g ) of the composite deter mined by applying the method of low frequency dielectric spectroscopy agree well with the T g values obtained by applying the method of dynamic mechanical analysis (DMA).