Under Thin-layer Interference Structures (TIS) [1,2] we'll understand antireflection systems with specific optical and structural properties, to the fundamental of which we can attribute the invariance of amplitude characteristics and total optical thickness of the structure on the number of periods and an opportunity of synthesis of such antireflection structures with layers' thicknesses significantly smaller than λ/4.

In the previous research of Thin-layer Interference Structures (TIS) only the normal incidence of the electromagnetic wave on the structures under consideration was studied [1,2]. However, in practice we often meet with oblique incidence of the waves on stratified structures. So in this paper we have studied the dependence of optical and spectral properties of TIS on the angle of incidence of plane wave. This analysis is based on following assumptions: 1. The medium, from which the wave is falling, is homogenous and half infinite. 2. The layers of antireflection coating are homogenous and bounded only in the direction, which is perpendicular to the plane of the structure. 3. The wave is plane and monochromatic. 4. The losses in layers are supposed to be absent.