Abstract

In this paper we present a coherent set of tools allowing an accurate and predictive design of low phase noise oscillators. Advanced phase noise modelling techniques in non linear microwave devices must be supported by a proven combination of the following : - Electrical modeling of low-frequency noise of semiconductor devices, oriented to circuit CAD . The local noise sources will be either cyclostationary noise sources or quasistationary noise sources. - Theoretically-based design rules are needed in order to define the most appropriate circuit architecture in function of the main characteristics to be optimized. For phase noise evaluation in feedback oscillators, the modified Leeson formula is a useful tool. Finally, results obtained with a 2 GHz HBT push-push VCO based on this methodology are presented.