Higgins, Ronan D. and Kooi, Jacob W.
Electrical standing waves in the HIFI HEB mixer amplifier
Proceedings of SPIE: Terahertz Technology and Applications II, 7215.
The Heterodyne Instrument for the Far-Infrared (HIFI) is one of three instruments to be launched aboard the
Herschel Space Observatory (HSO) in 2009. HIFI will provide unprecedented spectral sensitivity and resolution
between 490–1250 GHz and 1410–1910 GHz. In this paper, we report on the analysis of electrical standing waves
that are present between the hot electron bolometer (HEB) heterodyne mixing element and the first low noise
amplifier in the HIFI instrument. We show that the standing wave shape is not a standard sinusoid and difficult
to remove from the resulting spectrum using standard fitting methods. We present a method to remove the
standing waves based on data taken during the HIFI instrument level test, and anticipate the use of a similar
calibration procedure in actual flight. Using the standing wave profile we obtain direct evidence of the complex
IF output impedance of the HEB mixer.
||The authors thank the gas cell team for providing the data presented in this paper and Bertrand Delforge for
generating the gascell database and the tools to access it. Additionally the authors thank David Teyssier, Pourya
Khosropanah, Willem Jellema, Gert de Lange and Pieter Dieleman for their insights about HIFI and the HEB
IF chain. The authors would like to acknowledge the support of Enterprise Ireland (Prodex).
||HIFI; Herschel; HEB mixer; standing wave; impedance;
||Science & Engineering > Experimental Physics
||09 Mar 2011 17:04
|Journal or Publication Title:
||Proceedings of SPIE: Terahertz Technology and Applications II
||Society of Photo-optical Instrumentation Engineers (SPIE)
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