Design of Balanced Mixers for ALMA Band-10

Author

Shitov, Sergey V. ; Koryukin, Oleg V. ; Uzawa, Yoshinori ; Noguchi, Takashi ; Uvarov, Andrey V. ; Bukovski, Maksim A. ; Cohn, Ilya A.

Author_Institution

Japan Nat. Astron. Obs., Tokyo

Volume

17

Issue

2

fYear

2007

fDate

6/1/2007 12:00:00 AM

Firstpage

347

Lastpage

350

Abstract

Two variants of balanced mixer employing twin-SIS structure are under development for 787-950 GHz frequency range. Easy-to-use Geometry Transformation method for modeling of superconducting microstrips is developed, compared to referenced methods and used for design of the mixers. Lens-antenna mixer is based on cross-slot antenna; it does not need any intervening optics between its lens and sub-reflector of ALMA telescope; simple yet efficient composition of lens-antenna cartridge is suggested. Compact single-chamber balanced waveguide mixer employs two SIS chips and capacitive probe for LO injection; coupling above -3 dB and signal loss below -20 dB are expected. Need in shifting of resonance frequency of twin-SIS mixer towards top of the frequency band is predicted using Tucker´s theory in large-signal approximation. T_RX considerably below 200 K (DSB) is simulated using high-quality hybrid SIS junction for NbTiN/Nb - AlO_x - Nb/Al for J_c = 12 kA/cm².

Keywords

lens antennas; microstrip antennas; microstrip lines; superconductor-insulator-superconductor mixers; 3 dB loss; ALMA Band-10; Tucker´s theory; balanced mixers; compact single-chamber balanced waveguide mixer; geometry transformation method; intervening optics; lens-antenna cartridge; lens-antenna mixer; signal loss; superconducting microstrips; twin-SIS structure; Frequency; Geometrical optics; Lenses; Microstrip; Niobium; Optical waveguide theory; Optical waveguides; Solid modeling; Superconducting devices; Telescopes; ALMA project; SIS mixer; balanced mixer; lens antenna; superconducting microstrip line;

fLanguage

English

Journal_Title

Applied Superconductivity, IEEE Transactions on

Publisher

ieee

ISSN

1051-8223

Type

jour

DOI

10.1109/TASC.2007.897860

Filename

4277716