Cryogenic X-Band Low Noise Amplifiers

Paper in proceeding, 2007

This paper describes a number of cryogenic low noise amplifiers with very low noise for the frequency band 8.4-8.5 GHz. The amplifiers have been designed with different inputs: o standard coaxial o waveguide o coaxial followed by a high directivity 30 dB microstrip coupler At 10 K ambient temperature the three-stage partly InP-based amplifiers have a gain of 33.0+/-0.5 dB and a noise temperature of 5 -7K. The InP transistors used in the amplifiers were processed at Chalmers clean room facility in our own proprietary process.