O.E. Glukhova - Dr. Sc. (Phys.-Math.), Professor, Head of Department of Radiotechnique and Electrodynamics, Saratov State University named after N.G. Chernyshevsky E-mail: GlukhovaOE@info.sgu.ru A.A. Zyktin - Student, Department of Radiotechnique and Electrodynamics, Saratov State University named after N.G. Chernyshevsky E-mail: zyktin.a.a@gmail.com M.M. Slepchenkov - Ph. D. (Phys.-Math.), Associate Professor, Department of Radiotechnique and Electrodynamics, Saratov State University named after N.G. Chernyshevsky E-mail: slepchenkovm@mail.ru