Development of a new wideband heterodyne receiver system for the Osaka 1.85 m mm-submm telescope: Corrugated horn and optics covering the 210-375 GHz band
Abstract
The corrugated horn is a high-performance feed often used in radio telescopes. There has been a growing demand for wideband optics and corrugated horns in millimeter- and submillimeter-wave receivers as they improve observation efficiency and allow us to observe important emission lines such as CO in multiple excited states simultaneously. However, in the millimeter/submillimeter band, it has been challenging to create a conical corrugated horn with a fractional bandwidth of ~60% because the wavelength is very short, making it difficult to make narrow corrugations. In this study we designed a conical corrugated horn with good return loss, low cross-polarization, and symmetric beam pattern in the 210-375 GHz band (56% fractional bandwidth) by optimizing the dimensions of the corrugations. The corrugated horn was installed on the Osaka 1.85 m mm-submm telescope with matched frequency-independent optics, and simultaneous observations of 12CO, 13CO, and C18O (J = 2-1, 3-2) were successfully made. We describe the new design of the corrugated horn and report the performance evaluation results including the optics.
- Publication:
-
Publications of the Astronomical Society of Japan
- Pub Date:
- August 2021
- DOI:
- 10.1093/pasj/psab062
- arXiv:
- arXiv:2105.13605
- Bibcode:
- 2021PASJ...73.1116Y
- Keywords:
-
- instrumentation: detectors;
- radio lines: ISM;
- telescopes;
- Astrophysics - Instrumentation and Methods for Astrophysics
- E-Print:
- 22 pages, 15 figures, Accepted for publication in PASJ