Journal of Xidian University

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Design of an active cold noise source under the normal temperature condition

DONG Shuai1,2;WANG Zhenzhan1;HE Qiurui1,2;ZHANG Lei1,3   

  1. (1. CAS Key Lab. of Microwave Remote Sensing, National Space Science Center, Chinese Academy of Sciences, Beijing 100190, China;
    2. Univ. of Chinese Academy of Sciences, Beijing 100049, China;
    3. PLA Univ. of Science and Technology, Nanjing 210007, China)
  • Received:2015-12-17 Online:2017-02-20 Published:2017-04-01

Abstract:

In view of the limitation of the traditional microwave noise source in providing low brightness temperature noise, a new type of microwave cold noise source device is introduced. Based on the “ColFET” principle, the 2-port microwave network with output-port terminated noise temperature model is given. A design procedure of the active cold noise source (ACNS) is described, and an L-band ACNS using the GaAs high electron mobility transistor is reported. A noise injection radiometer has been developed to perform the measurements. The L-band ACNS works at 302K, and exhibits a noise temperature of less than 85.3K in the 1400~1430MHz frequency band. Test results show that the ACNS can be used as a microwave radiometer calibration cold source.

Key words: active cold noise source, radiometers, calibration, remote sensing, high electron mobility transistor