Electromagnetic wave scattering by a thin layer in which many small particles are embedded

Scattering of electromagnetic (EM) waves by many small particles (bodies), embedded in a thin layer, is studied. Physical properties of the particles are described by their boundary impedances. The thin layer of depth of the order $O(a)$ with many embedded in it small particles of characteristic size $a$, is described by a boundary condition on the surface of the layer. The limiting interface boundary condition is obtained for the effective EM field in the limiting medium, in the limit $a\to 0$, where the number $M(a)$ of the particles tends to infinity at a suitable rate.