Diffraction of Electromagnetic Waves by Nanoobjects With Internal Structure

This paper studies the problem of diffraction of electromagnetic waves on an object containing an arbitrary number of layers of materials with different permittivity and permeability. It is assumed that the typical size of the object is much smaller than the wavelength of the incident wave. In other words, we adopt long-wave approximation and the ratio of these values k is considered a small parameter. In this case, the electromagnetic field can be described by an integral equation using the Stratton-Chu formula. The solution of this equation is sought in the form of a multipole expansion at large distances from the object and in the form of an expansion in the small parameter k in the vicinity of the object. The coefficients in these expansions are determined by solving a recurrence system of electrostatic problems. To illustrate the approach, we consider diffraction of the electromagnetic wave on a cylinder whose cross section consists of two eccentric circles. The proposed scheme for solving diffraction problems is quite simple and does not impose any restrictions on the dielectric and magnetic permeability of the layers. It can be used in the calculation of the scattered electromagnetic field on metal structures as well as on nanoobjects containing layers of metamaterials.