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Proceedings Paper

A 275- to 370-GHz SIS mixer for the APEX telescope
Author(s): Christophe Risacher; Victor Belitsky; Vessen Vassilev; Alexey Pavolotsky
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Paper Abstract

Atacama Pathfinder EXperiment (APEX) submillimeter telescope is currently under completion on Chajnator, at an altitude of 5050 m on the Atacama Desert, in the Northern Chile. The telescope facility heterodyne receivers should have 3 bands covering 211-500 GHz. We present design of a 275-370 GHz SIS mixer to be used as a first light APEX Band 2 receiver. A novel waveguide-to-microstrip transition with integrated bias-T is used in this mixer. This structure allows coupling of the RF signal from a full height waveguide to a thin-film superconducting line via E-probe. The wide side of the probe is connected to another port via a specially shaped high impedance line that provides RF/DC isolation. This port is used to extract the IF signal and to inject a DC current that creates a local magnetic field parallel to the plane of the SIS junction to suppress the Josephson effect. The main advantage of this type of Josephson suppression circuit is its compactness as it uses the existing superconducting lines from the SIS integrated tuning circuitry. The entire structure with the probe, SIS junction with its tuning circuitry is placed on a quartz substrate. For more advanced designs, as a sideband separating or balanced mixer that we intend to have for the final version of the APEX telescope heterodyne receiver, the SIS junctions of two balanced or quadrature mixers will be at a very close distance. The standard solution of using superconducting coils to suppress Josephson effect is very difficult to implement and, therefore, this new structure should be of a great advantage.

Paper Details

Date Published: 8 October 2004
PDF: 9 pages
Proc. SPIE 5498, Millimeter and Submillimeter Detectors for Astronomy II, (8 October 2004); doi: 10.1117/12.550333
Show Author Affiliations
Christophe Risacher, Onsala Space Observatory/Chalmers Univ. of Technology (Sweden)
Victor Belitsky, Onsala Space Observatory/Chalmers Univ. of Technology (Sweden)
Vessen Vassilev, Onsala Space Observatory/Chalmers Univ. of Technology (Sweden)
Alexey Pavolotsky, Onsala Space Observatory/Chalmers Univ. of Technology (Sweden)


Published in SPIE Proceedings Vol. 5498:
Millimeter and Submillimeter Detectors for Astronomy II
Jonas Zmuidzinas; Wayne S. Holland; Stafford Withington, Editor(s)

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