Cold noise generated by a microwave transistor

Microwave noise generators based on the GaAs field-effect transistors (FET) which can be used instead of low-temperature noise generators with cryogenic cooling are designed. The generator cascade and device circuit are simulated for various types of FETs in the frequency band 1-40 GHz. The frequency dependences of the minimum attainable noise temperatures of output radiation are obtained for individual devices designed according to the proposed circuit. The results are extended over the entire frequency band mentioned above. Experimental data justifying the model developed are discussed.