E.V. Mitrofanov - Post-graduate Student, Graduate Research Scientist, Kotel\'nikov Institute of Radioengineering and Electronics of RAS. E-mail: mitrofanov_ireran@mail.ru V.A. Cherepenin - Dr. Sc. (Phys.-Math.), Professor, Corresponding Member of RAS, Kotel\'nikov Institute of Radioengineering and Electronics of RAS. E-mail: cher@cplire.ru