摘要
This paper presents an ultra-low noise L-band radio astronomical cryogenic receiver for the Fivehundred-meter Aperture Spherical radio Telescope(FAST) telescope. The development of key low noise microwave parts of coupling low noise amplifier(Coupling-LNA) and conical quad-ridge orthogonal mode transducers(OMT) and reasonable system integration achieve outstanding performance of receiver. It covers the frequency range of 1.2 GHz to 1.8 GHz. Novel cryogenic Coupling-LNAs with low noise, large return loss, high dynamic range and the function of coupling calibration signals are developed for the proposed receiver. Amplification and coupling function circuits are integrated as a single Coupling-LNA with full noise temperature of 4 K at the physical temperature of 15 K. Its return loss is more than 18 d B, and output1 d B compression power is +5 d Bm. A cryogenic dewar is fabricated to provide 55 K and 15 K cryogenic environment for OMT and Coupling-LNAs, respectively. The receiver's system noise temperature is below9 K referred to feed aperture plane. Benefiting from optimal design and precise mechanical treatment, good scattering performance of OMT and equalized radiation patterns of horn are achieved with an antenna efficiency above 75%.
作者
Hong-Fei Liu
Chuan He
Jin Wang
Peng Jiang
Sheng-Wang Wang
Yang Wu
Hang Zhang
Jin-You Song
Xiang-Wei Shi
Ming-Lei Guo
刘鸿飞;何川;王进;姜鹏;王生旺;伍洋;张航;宋金友;石向玮;郭明雷(National Astronomical Observatories,Chinese Academy of Sciences,Beijing 100101,China;CAS Key Laboratory of FAST,National Astronomical Observatories,Chinese Academy of Sciences,Beijing 100101,China;The 16th Research Institute of China Electronics Technology Group Corporation,Hefei 230043,China;The 54th Research Institute of China Electronics Technology Group Corporation,Shijiazhuang 050081,China)
基金
supported by the National Key R&D Program of China(2018YFE0202900)
the National Natural Science Foundation of China(U1831110)。