VHF/UHF Cryogenic LNA for Deep Space Exploration and Radio Astronomy

The receiver plays a very important role in the research field of deep space exploration and radio astronomy, and the cryogenic low noise amplifier (LNA) is the key component of their receiving system. The LNA's noise performance is greatly improved when operating at extremely low temperatures. In this paper, we designed a VHF/UHF cryogenic LNA. The LNA adopts the topology of two-stage cascaded amplification. By adopting the structure of series negative feedback and parallel negative feedback and accurate input and output matching, it not only realizes the optimization of input return loss and noise, but also broadens the operating bandwidth and improves stability. Based on this structure, the design of a broadband LNA with high gain, low noise, and better return loss is realized in this paper. This design is tested at 300 K, 77 K, and 15K respectively. The experimental results show that the gain of the VHF/UHF (100-700 MHz) LNA is greater than 32.3 dB, the return loss of the input and output ends are better than 10 dB, and the noise temperature is less than 95.83 K at 300 K, the noise temperature is less than 23.83 K and 17.90 K at the physical temperature of 77 K and 15 K, respectively.