Low-Noise Waveguide-Type NbN/AlN/NbN SIS Mixers Approaching Terahertz Frequencies

Author

Shan, Wenlei ; Takeda, Masanori ; Kojima, Takafumi ; Uzawa, Yoshinori ; Shi, Shengcai ; Noguchi, Takashi ; Wang, Zhen

Author_Institution

Purple Mountain Obs., Chinese Acad. of Sci., Nanjing, China

Volume

58

Issue

4

fYear

2010

fDate

4/1/2010 12:00:00 AM

Firstpage

841

Lastpage

848

Abstract

In this paper, we present the development of low-noise waveguide mixers with NbN/AlN/NbN tunnel junctions at a frequency approaching 1 THz. The mixer was designed to be compatible with MgO substrate. Mixers of the presented design demonstrated much improved receiver sensitivity. This improvement is attributed to the reduction in signal dissipation in waveguide and leakage into an intermediate frequency port by adopting a full-height waveguide and an effective RF choke filter, respectively. Two types of tuning circuits, namely parallel-connected twin-junction (PCTJ) and half-wavelength self-resonance distributed junction (DJ), are designed and evaluated. Both theoretical and experimental results show that the PCTJ design is superior to the DJ design in terms of gain and sensitivity due to smaller loss in the tuning circuit.

Keywords

microwave mixers; terahertz waves; tuning; waveguides; RF choke filter; half wavelength self-resonance distributed junction; intermediate frequency port; low noise waveguide mixers; parallel connected twin junction; receiver sensitivity; signal dissipation; substrate; terahertz frequencies; tuning circuits; tunnel junctions; Full height waveguide; MgO substrate; NbN/AlN/NbN SIS mixer; RF choke filter; noise temperature; waveguide–microstrip transition;

fLanguage

English

Journal_Title

Microwave Theory and Techniques, IEEE Transactions on

Publisher

ieee

ISSN

0018-9480

Type

jour

DOI

10.1109/TMTT.2010.2042643

Filename

5427118