Bias Power Supply Design for a Cryogenic HEMT Low Noise Amplifier

High electronic mobility transistor(HEMT) is widely used in the high sensitivity(low noise) radio astronomy receivers. Cooling a HEMT-based amplifier to 15K decreases the noise temperature by a factor of ten(and increases gain by about 3dB) compared to room temperature values. But only under the specific bias condition, the HEMT can obtain the optimal low noise, high gain and high stability. A approach to implement a bias power supply having properties of adjustable, super-stable, high reliability with remote monitoring function for multi-stage cryogenic HEMTs is provided in this paper. The correctness and feasibility of the approach have been verified by testing and late application.