Advanced Physical Research

This study examines the influence of grain boundary scattering on the skin effect in semi-infinite polycrystalline metals. Using the Fourier transform method within the framework of kinetic theory, we calculate the surface impedance assuming specular reflection of electrons. Our numerical analysis reveals that the presence of grain boundaries significantly degrades the bulk conductivity, leading to a drastic enhancement of the surface resistance. This modification results in a markedly higher normalized dissipation (surface-resistance) coefficient and a deeper penetration of the electromagnetic field (increased skin depth) compared to the ideal single-crystal case. Specifically, the polycrystalline structure markedly increases the electromagnetic field penetration into the metal, i.e., reduces its screening efficiency, and makes it significantly more lossy. These results demonstrate that the classical description of the skin effect is insufficient for polycrystalline materials and provide a corrected model for evaluating their electromagnetic shielding and absorption properties.