G.F. Zargano - Dr. Sc. (Phys.-Math.), Professor, Head of Department of Radiophysics, Southern Federal University (Rostov-on-Don). E-mail: zargano@yandex.ru V.V. Zemlyakov - Ph. D. (Phys.-Math.), Associate Professor, Southern Federal University (Rostov-on-Don). E-mail: vvzem@yandex.ru S.V. Krutiev - Post-graduate Student, Department of Radiophysics, Southern Federal University (Rostov-on-Don). E-mail: sergey-kryt@yandex.ru