Optimization of an ultra low-phase noise sapphire--SiGe HBT oscillator using nonlinear CAD.

In this paper, the electrical and noise performances of a 0.8 microm silicon germanium (SiGe) transistor optimized for the design of low phase-noise circuits are described. A nonlinear model developed for the transistor and its use for the design of a low-phase noise C band sapphire resonator oscillator are also reported.