M.V. Davidovich – Dr.Sc.(Phys.-Math.), Professor,
Department of Radiotechnique and Electrodynamics,
Saratov National Research State University named after N. G. Chernyshevsky
E-mail: davidovichmv@info.sgu.ru
A.K. Kobets – Post-graduate Student,
Department of Solid State Physics, Saratov National Research State University named after N. G. Chernyshevsky E-mail: cobets.alexander@yandex.ru