Program and Abstract Book - SRON

19 th International Symposium on Space Terahertz Technology
10-5
Development of a Waveguide-Type Dual-polarization Sideband-Separating
SIS Receiver System in 100 GHz Band for the NRO 45-m Radio Telescope
Taku Nakajima 1 Masayuki Kawamura 1 Kimihiro Kimura 1 Yoshinori Yonekura 1 Hideo Ogawa 1
Takeshi Sakai 2 Nario Kuno 2 Masato Tsuboi 3 Shin’ichiro Asayama 4 Takashi Noguchi 4 Ryohei Kawabe 2
1. Department of Physical Science, Graduate School of Science, Osaka Prefecture University
2. Nobeyama Radio Observatory, National Astronomical Observatory of Japan
3. Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency
4. Advanced Technology Center, National Astronomical Observatory of Japan
We have developed a waveguide-type dual-polarization
sideband-separating SIS receiver system in 100 GHz
band for the 45-m radio telescope at the Nobeyama
Radio Observatory, Japan. The new receiver uses a
waveguide-type Ortho-Mode Transducer (OMT) and
two Sideband-Separating (2SB) SIS mixers (Fig.1). The
SSB receiver noise temperature with 4.0-8.0 GHz IF,
including the noise contribution from the vacuum
window, the feed horn, and the IF amplifier chain, are
measured to be lower than 100 K over the RF range of
75-120 GHz, and the minimum value of ~ 45 K is achieved at around 95 GHz. The mean value and
standard deviation between RF frequency range of 75-106 GHz in the LSB and 79-120 GHz in the USB
are 68 13 K and 66 9 K, respectively (Fig.2 (a)). The measured IRR was better than 10 dB over the RF
range of 80-123GHz. The mean value between RF frequency range of 80-111 GHz in the LSB and 84-123
GHz in the USB are 20 dB and 19 dB, respectively (Fig.2 (b)). The new receiver system has been
installed in the telescope, and we successfully detected the molecular lines over the RF range of 80-116
GHz toward Orion KL in 2007 December. These are the first astronomical observations with the
waveguide-type dual-polarization sideband-separating SIS receiver system in the 100 GHz band. A
molecular line survey using this receiver system has already begun.
200
40
150
USB
LSB
30
USB
LSB
100
20
50
10
0
70 80 90 100 110 120 130
RF Frequency [GHz]
0
70 80 90 100 110 120 130
RF Frequency [GHz]
86