Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE
Spaceborne 640-GHz SIS receiver based on a 4-K mechanical cooler
Yasunori Fujii, Ken'ichi Kikuchi, Junji Inatani, Yoshihisa Irimajiri, Masumichi Seta, Satoshi Ochiai, Takeshi Manabe, Harunobu Masuko, Takeshi Noguchi, Katsuhiro Narasaki, Shoji Tsunematsu, Toshiya Shirota
Abstract
An engineering model has been built for a space-borne 640- GHz SIS receiver. It is the key component of Superconducting Submillimeter-Wave Limb-Emission Sounder, which is to be operated aboard the Japanese Experiment Module of the International Space Station in 2005. The receiver includes two Superconductor-Insulator-Superconductor (SIS) mixers cooled at 4.5 K, as well as four High-Electron-Mobility- Transistor (HEMT) amplifiers, two of which cooled at 20 K and the other two at 100 K. These components are integrated in a compact cryostat with two-stage Stirling and Joule- Thomson refrigerators. The receiver components has been successfully cooled and the cryostat has survived random vibration tests. The 640-GHz SIS mixer, which uses a pair of Nb/AlOx/Nb junctions connected in parallel, is built so that a broad RF matching be achieved without mechanical tuners. It is followed by cooled low noise HEMT amplifiers with a noise temperature of less than 17 K. The total receiver noise temperature has been measured around 180 - 220 K over the bandwidth of 5.5 GHz.