Low Noise 1 THz SIS Mixer for Stratospheric Observatory: Design and Characterization

Author

Karpov, Alexandre ; Miller, David A. ; Stern, Jeffrey A. ; Bumble, Bruce ; LeDuc, Henry G. ; Mehdi, Imran ; Lin, Robert H. ; Zmuidzinas, Jonas

Author_Institution

Phys. Department, California Inst. of Technol., Pasadena, CA, USA

Volume

21

Issue

3

fYear

2011

fDate

6/1/2011 12:00:00 AM

Firstpage

616

Lastpage

619

Abstract

We report the development of a low noise SIS mixer aimed for 1 THz channel of the Caltech Airborne Submillimeter Interstellar Medium Investigations Receiver (CASIMIR), designed for the Stratospheric Observatory for Far Infrared Astronomy (SOFIA). The mixer uses Nb/Al-AlN/NbTiN SIS junctions with critical current density of about 45 kA/cm². The junctions are shaped in order to optimize the suppression of the Josephson DC currents. We used a double slot planar antenna to couple the mixer chip with the telescope beam. The RF matching microcircuit is made using Nb and gold films. The mixer IF circuit is designed to cover 4-8 GHz band. The test receiver with the new mixer has the low noise operation in a 0.9-1.05 THz band. The minimum DSB receiver noise measured at 1 THz is 260 K (Y=1.64) , apparently the lowest reported up to date.

Keywords

Josephson effect; astronomical observatories; astronomical telescopes; infrared astronomy; infrared sources (astronomical); planar antennas; slot antennas; superconducting junction devices; superconductor-insulator-superconductor mixers; CASIMIR; Caltech Airborne Submillimeter Interstellar Medium Investigations Receiver; Josephson DC current; RF matching microcircuit; SIS junction; SOFIA; critical current density; double slot planar antenna; far infrared astronomy; frequency 0.9 GHz to 1.05 GHz; frequency 1 THz; frequency 4 GHz to 8 GHz; low noise SIS mixer; mixer IF circuit; stratospheric observatory; superconductor-insulator-superconductor mixer; telescope beam; Junctions; Mixers; Niobium; Noise; Noise measurement; Receivers; Temperature measurement; Niobium alloys; THz technology; radio astronomy; submillimeter wave receivers; superconductor-insulator-superconductor mixers;

fLanguage

English

Journal_Title

Applied Superconductivity, IEEE Transactions on

Publisher

ieee

ISSN

1051-8223

Type

jour

DOI

10.1109/TASC.2011.2124437

Filename

5737778