Issue |
A&A
Volume 640, August 2020
|
|
---|---|---|
Article Number | L9 | |
Number of page(s) | 6 | |
Section | Letters to the Editor | |
DOI | https://doi.org/10.1051/0004-6361/202038713 | |
Published online | 04 August 2020 |
Letter to the Editor
Demonstration of a wideband submillimeter-wave low-noise receiver with 4–21 GHz IF output digitized by a high-speed 32 GSps ADC
1
National Astronomical Observatory of Japan (NAOJ), Osawa 2-21-1, Mitaka, Tokyo, Japan
e-mail: t.kojima@nao.ac.jp
2
Graduate University for Advanced Studies (SOKENDAI), Mitaka, Tokyo 181-8588, Japan
3
The University of British Columbia, Vancouver, BC V6T 1Z4, Canada
4
Keysight Technologies Deutschland GmbH, Böblingen, Baden-Württemberg 71034, Germany
5
Keysight Technologies Japan K.K., Hachioji, Tokyo 192-8550, Japan
Received:
22
June
2020
Accepted:
13
July
2020
We report on a 275–500 GHz heterodyne receiver system in combination with a wideband intermediate-frequency (IF) backend to realize 17 GHz instantaneous bandwidth. The receiver frontend implements a heterodyne mixer module that integrates a superconductor-insulator-superconductor (SIS) mixer chip and a cryogenic low-noise preamplifier. The SIS mixer is developed based on high-current-density junction technologies to achieve a wideband radio frequency (RF) and IF bandwidth. The IF backend comprises an IF chain divided into two channels for 4.0–11.5 GHz and 11.3–21.0 GHz and an analog-to-digital converter (ADC) module that is capable of high-speed sampling at 32 Giga samples per second with 12.5 GHz bandwidth per channel and an effective number of bits of 6.5. The IF backend allows us to simultaneously cover the full 4–21 GHz IF range of the receiver frontend. The measured noise temperature of the receiver frontend was below three times the quantum noise (hf/kB) over the entire RF band. A dual-polarization sideband-separating receiver based on this technique could provide up to 64 GHz of instantaneous bandwidth, which demonstrates the possibility of future wideband radio astronomical observations with advanced submillimeter-wave heterodyne receivers.
Key words: instrumentation: detectors / techniques: spectroscopic
© ESO 2020
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