The Method for Calculation of the Coefficient of Reflection of an Electromagnetic Wave from an Inhomogeneous Layer Having a Small Phase Thickness

Analytical expressions for the coefficient of reflection of an electromagnetic wave from a planeparallel layer with an arbitrary profile of the permittivity are obtained. It is shown that the electromagnetic model of a layer with a small phase thickness can be obtained with the help of the perturbation theory method. A method is proposed for the calculation of the reflection coefficient. The method is based on the combination of formulas of the perturbation theory and the formulas describing reflection from a homogeneous layer. The obtained expressions are compared with the numerical solutions of the electromagnetic equations. It is determined that the combined formulas describe the angular dependence of the reflection coefficient better than the formulas obtained only with the help of the perturbation theory.