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The polarization-angular dependences of the reflection and transmission coefficients of free plane-parallel ice plates in the region of 0°С, when flat electromagnetic waves of s-and p-polarization fall on them and are recorded by an L-band radiometer 1.41 GHz are studied theoretically. It is shown that the observation of interference effects in ice plates in the L-range is limited to a plate thickness of 4.3 meters. This limitation is due to a radiometer bandwidth of 20 MHz. Ice is considered an isotropic or uniaxial crystal with an anisotropy coefficient of 15%. Three types of directions of the anisotropy axis are considered in the assumptions of the quasianisotropic medium model. The value of the Brewster angle is obtained, and it is shown that it does not depend on anisotropy. Reflective and anti-reflective effects are associated with a change in wavelength in the direction perpendicular to the surface of the plate. In turn, this length depends on the angle of incidence, polarization, and direction of the anisotropy axis. The possibility of forming interference regions of transparency for certain thicknesses is shown, the reflection coefficients for both polarizations are significantly reduced, and the transmittances increase. Interference areas of transparency can be formed both at the Brewster angle and at other angles. These effects are associated with interference phenomena and their enhanced effect of anisotropy.

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Abstract. The study of the Fourier-images properties was made by numerical methods for the family of flat triadic geometric prefractals with generator in the form of symmetric four-stage broken line with an arbitrary angle at the apex between the central units and the initiator in the form of a straight line (Koch curve) or in the form of an equilateral triangle (the Koch snowflake). To obtain the Fourier images the pictures of fractals were approximated by a grid function on a uniform grid with cells small enough for adequate mapping of high generation prefractal details, and then were digitized in order to use fast Fourier transform for determination the values of the squared modules of the Fourier component, that is, the spectral intensity distribution of diffraction maxima in the Fraunhofer region. An analysis showed that for the values of the vertex or base angles equal to the integer fraction of 180 degrees, Fourier images are the same as for the perfect crystals with the symmetry axes of the 2-nd, 3-th, 4-th and 6-th order, or as for parcuet mosaics or quasicrystals with the axes of quasisymmetry of any order. Really in the Fourier images of the Koch curves with the initiator in the form of a straight line was observed axis of quasisymmetry from 3rd to 9 th and 11-th order. Similar to the above-described properties are also inherent to Fourier images of the Koch snowflake with the initiator in the form of an equilateral triangle. The configuration of the observed Fourier images can be approximately regarded as a radial-annular, at that in the peripheral ("lattice") of the images is dominated by the radial nature of the frequency distribution of diffraction reflections along the radius, and in the central ("fractal") -a ring with self-similarity. The lattice part has a kind of clustering: all the rays have a strong central chain of reflexes along the radii and parallel to it the weaker satellites on both sides. All Fourier images had the center of symmetry, which is an integral attribute of the diffraction patterns in the Fraunhofer zone for any objects, however, the rotational symmetry was not perfect: the positions of the diffraction reflexes when rotating images at angles that correspond to the order of the symmetry axis remain unchanged, but their intensity could vary. The cause of the observed features is that prefractals, unlike crystals, are not a continuum of point objects but two-dimensional set of equal length line segments with different orientation in space. In this set for the considered configurations of the generator it is possible to allocate several two-dimensional subsets with equally oriented segments, each of which contains a number of partial one-dimensional diffraction gratings formed by segments located along the same line. These parallel lattice in the general case contain a different number of segments, and the degree of filling and the distance between adjacent segments, determining the intensity and diffraction reflections distribution structure along the line, depend on the orie...

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