D.A. Usanov - Dr. Sc. (Phys.-Math.), Professor, Head of Department of Solid-State Physics, Saratov State University named after N.G. Chernyshevsky E-mail: usanovda@info.sgu.ru V.P. Meschanov - Dr. Sc. (Eng.), Professor, Director of NIKA-Microwave, Ltd (Saratov) E-mail: nika373@bk.ru A.V. Skripal - Dr. Sc. (Phys.-Math.), Professor, Department of Solid-State Physics, Saratov State University named after N.G. Chernyshevsky E-mail: skripala_v@info.sgu.ru N.F. Popova - Ph. D. (Eng.), Senior Research Scientist, Deputy Director , NIKA-Microwave, Ltd (Saratov) E-mail: nika373@bk.ru D.V. Ponomarev - Ph. D. (Phys.-Math.), Associate Professor, Department of Solid-State Physics, Saratov State University named after N.G. Chernyshevsky E-mail: ponomarev87@mail.ru