Application of Complex Negative Feedback Technology in Broadband Active Microwave Cold Noise Source

Aiming at the contradiction between output low temperature noise performance and working bandwidth in the design of C-band broadband active microwave cold noise source, in this paper the ATF38143 GaAs-based pseudomorphic high electron mobility transistor (pHEMT) of Avago company is selected to design a C-band broadband active microwave cold noise source. The series and parallel negative feedback circuit topology improves the working bandwidth while ensuring the low-temperature noise output performance. Its center frequency is 6.95 GHz, the working bandwidth is 1.3 GHz, and the relative bandwidth is 18.7%. Its lowest in-band output noise temperature is 141. 62 K under the normal temperature conditions, and the working frequency band can cover the three channels of the C-band microwave radiometer center frequency points of 6.60 GHz, 6.93 GHz, and 7.30 GHz.