Title :
Development of a waveguide NbN-based SIS mixer in the 900-GHz band
Author :
Takeda, Masanori ; Uzawa, Yoshinori ; Wang, Zhen ; Saito, Atsushi ; Kawakami, Akira
Author_Institution :
Kansai Adv. Res. Center, Commun. Res. Lab., Kobe, Japan
fDate :
6/1/2003 12:00:00 AM
Abstract :
We have designed and fabricated waveguide superconductor-insulator-superconductor (SIS) receivers at 870 GHz with NbN/AlN/NbN tunnel junctions on an MgO substrate. A waveguide probe was incorporated into the mixer chip for a waveguide-to-microstrip transition. As the tuning circuit for the SIS mixer, we designed a resonant distributed junction whose length is one wavelength and critical current density is 20 kA/cm2. The mixing properties were calculated based on the quantum theory of mixing. The SSB mixer noise temperature should be less than 100 K and conversion gain larger than -8.0 dB in the frequency range from 840 to 920 GHz. We also observed the resonance steps of the fabricated SIS mixer. The tuning frequency was slightly higher than the designed frequency.
Keywords :
circuit tuning; critical current density (superconductivity); microstrip transitions; niobium compounds; submillimetre wave mixers; superconductor-insulator-superconductor mixers; waveguide transitions; -8.0 dB; 840 to 920 GHz; MgO; MgO substrate; NbN-AlN-NbN; NbN/AlN/NbN tunnel junction; SSB mixer noise temperature; critical current density; quantum theory; resonant distributed junction; terahertz band; tuning circuit; waveguide SIS mixer; waveguide probe; waveguide-to-microstrip transition; Circuit optimization; Frequency; Josephson junctions; Mixers; Probes; RLC circuits; Resonance; Superconducting devices; Waveguide junctions; Waveguide transitions;
Journal_Title :
Applied Superconductivity, IEEE Transactions on
DOI :
10.1109/TASC.2003.814003
