A Non-linear Noise Model of Bipolar Transistors for the Phase-Noise Performance Analysis of Microwave Oscillators

An empirical nonlinear noise model for bipolar transistors, deriving from the charge-controlled nonlinear noise (CCNN) modelling approach, has been developed and implemented. The noise model of a GaInP-GaAs HBT device has been experimentally characterized on the basis of both bias-dependent low-frequency noise data and a set of phase-noise measurements. To this aim, a special-purpose laboratory set-up has been implemented, which allows for phase-noise measurements on an on-wafer device sample under a wide set of different large-signal oscillating conditions. Good agreement was found between the predicted performance and the phase-noise measurements carried out on a MMIC VCO designed by using the proposed non-linear noise model.