A unified approach to RF and microwave noise parameter modeling in bipolar transistors

A unified approach to RF and microwave noise parameter modeling in bipolar transistors is presented. Circuit level noise parameters including the minimum noise figure, the optimum generator admittance, and the noise resistance are analytically linked to the fundamental noise sources and the y-parameters of the transistor through circuit analysis of the chain noisy two-port representation. Comparisons of circuit level noise parameters from different physical models of noise sources in the transistor were made against measurements in UHV/CVD SiGe HBTs. A new model for the collector shot noise is then proposed which produces better noise parameter agreement with measured data than the SPICE noise model and the thermodynamic noise model, the two most recent Y-parameter based noise models.