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Experimental Study of Superconducting Left Handed Tunable Transmission Lines.

Muhammad Usman
Новых материалов и нанотехнологий (ИНМиН)
Теоретической физики и квантовых технологий
Академическая группа
Superconducting Metamaterial Laboratory
Научный руководитель
PhD, prof. Shitov S.
Название тезиса
Experimental Study of Superconducting Left Handed Tunable Transmission Lines.

Concept for pulse magnetic control of phase delay in superconducting transmission lines for frequency range up to 20 Ghz is being developed using special integration technique. The concept of tunable left to right( L2R) and Right to left (R2L) transmission lines is used for arrangement of CPW(Coplanar Wave Guide)  loaded with resonant circuits containing dc-Squids and connected in series and parallel  to the central conductor of the CPW. The circuits are designed according to rules of 2 micro meter Nb-Al/AlOx-Nb (Jc= 0.1kA/cm^2) technology and compared with ideal models for number of cells of 40 ( up to 130). It is shown that characteristics impedance of new dispersive transmission lines can be increased above 30 ohm in a wide frequency range. A thin film attenuator as an extra matching element is designed for further suppression of standing waves. We found the rejection band in R2L transmission line due to joint effect of moderated phase velocity(up to 100 times and above) and physical size of the elementary cell (70micro meter) the rejection band can be negligibly small with L2R transmission line along with infinite phase velocity in the middle of its band if simultaneous tuning frequency for both parallel and series resonant circuits is provided. 

We demonstrate via EM modeling that the practicable  2D array bearing the interface between LHTL and RHTL areas may behave like an interface of 2D Veselago Lens.