Abstract : Our research activities related to noise characterisation and modelling of microwave active devices are summarised in this report. The first part is dedicated to noise measurement up to K band. The accuracy of noise parameter extraction methods, the instrumentation and the different noise measurement procedures are described. The noise characterisation at cryogenic temperature for very low noise applications is also investigated. The extension of the test set in the low frequency range (L, S and VHF bands) allows the precise determination of noise performance of active devices in a large frequency range. The second part of this work is related to the noise modelling of microwave transistors. The techniques to derive the small signal equivalent circuit are presented. Thermal and shot noise sources are added to the latters to describe the noise behaviour of Field Effect Transistors (FET) and Heterojunction Bipolar Transistors (HBT) in the microwave frequency range. The noise behaviour of these devices at cryogenic temperatures (77K) and under optical illumination is also investigated in this part.