Exact noise figure model for ultra low noise microwave bipolar transistors

In order to effect an optimum trade-off of various device parameters to achieve ultra low noise figure at or above 4 GHZ, a much more accurate model based strictly on the measurable physical parameters is required. We have introduced a distributed equivalent circuit with distributed noise sources and current generators. All of the parameters including the current gain factor have been calculated from the first principle. Unlike all of the previous device models, the effect of multiplicity of the emitter finger is carefully taken into account in the present model.