Elimination of the feed-through effect in vortex flow transistors

Author

Ketkar, M.A. ; Beyer, J.B. ; Nordman, J.E. ; Hohenwarter, G.K.G.

Author_Institution

Dept. of Electr. & Comput. Eng., Wisconsin Univ., Madison, WI, USA

Volume

27

Issue

2

fYear

1991

fDate

3/1/1991 12:00:00 AM

Firstpage

3293

Lastpage

3296

Abstract

The capacitive feed-through effect in a VFT (vortex flow transistor) has been identified as a major limiting factor for high-frequency distributed amplifier applications. Two techniques to eliminate this effect are proposed and discussed. They are the use of a balanced controlled VFT and the use of a modified super current injection transistor. The balanced controlled configuration consists of a pair of Josephson junctions driven by control lines excited by push-pull. The simulations show more than 100-dB improvement in S12 over a single-ended device up to 175 GHz. The modified superconducting current injection transistor is a current controlled current source allowing the output line to be fed against ground. Hence, capacitive feed-through effects are greatly reduced. Device layouts and fabrication techniques are discussed

Keywords

Josephson effect; flux flow; superconducting junction devices; Josephson junctions; VFT; balanced controlled configuration; current controlled current source; device layouts; fabrication techniques; feed-through effect; high-frequency distributed amplifier applications; modified super current injection transistor; single-ended device; vortex flow transistors; Bandwidth; Cutoff frequency; Distributed amplifiers; Fabrication; Impedance; Josephson junctions; Magnetic fields; Superconducting microwave devices; Transmission line theory; Voltage control;

fLanguage

English

Journal_Title

Magnetics, IEEE Transactions on

Publisher

ieee

ISSN

0018-9464

Type

jour

DOI

10.1109/20.133916

Filename

133916