Empirical Nonlinear Noise Models of Field-Effect Devices for Microwave Circuit Large-Signal Noise Analysis

Measurement-based, circuit-oriented non-linear noise modelling of field-effect devices is an important issue in the design of micro- and millimeter-wave circuits, such as low-phase noise oscillators and mixers. When accurate large-signal (LS) noise analysis predictions are needed for non-linear circuit design, the active device noise models require not only a suitable characterization of the figures describing the linear noise behavior of the device within the RF-band, but also an adequate description of those non-linear mechanisms, which are responsible for the modulation of broad-band noise and the up-conversion to RF of low-frequency (LF) noise phenomena. In this contribution, the basic problems to be faced in the empirical non-linear noise modelling of field-effect active devices are discussed, by examining both the link with distributed microscopic physical noise sources and the predictive capabilities in LS analyses of equivalent, lumped cyclostationary noise generators. Measurement procedures aimed at the extraction of cyclostationary equivalent noise generators will be outlined. Examples of implementation of the non-linearly controlled noise sources in the framework of commercial CAD packages will be provided, and some examples of application of the non-linear noise models to the analysis and design of microwave circuits will be discussed.