Bias Network Noise effects modeling for RF amplifiers and MCM for Space Application

When designing an RF module from an early stage, the procedure starts with the definition of a list of system requirements that shall be flow-downed to each subsystem specification. One of the most challenging specifications is related to the spurious and its influence in other parameters such as linearity, noise figure, voltage spikes, S/I, etc. Concerning to carrier related spurious, the biasing networks usually have decoupling elements to mitigate noise effects. Nevertheless, if any noise source is not detected and considered in the design, the noise level could overcome the system specification, degrading its performance. The contribution in this paper is to stablish an easy prediction method, through the use of well-known characteristics of analog modulations (AM) and usual RF/DC figures, to estimate the carrier related spurious when a noise source from the biasing network is coupled into the RF system. To demonstrate the validity of the prediction method, a set of tests over different RF components is accomplished, as well as some measurements over a Multi-Chip Module (MCM), once the model has been extrapolated to complex systems.