A.A. Galiev − Post-graduate Student,

Department of Radiophysics, Kazan Federal University, Institute of Physics

E-mail: ggalievv@mail.ru

A.I. Sulimov − Ph.D. (Phys.-Math.), Associate Professor,

Department of Radiophysics, Kazan Federal University, Institute of Physics

E-mail: asulimo@gmail.com

A.V. Karpov − Dr.Sc. (Phys.-Math.), Professor,

Department of Radiophysics, Kazan Federal University, Institute of Physics

E-mail: arkadi.karpov@kpfu.ru