Chapter 3 - Characterization and Modeling of High-Frequency Active Devices Oriented to High-Sensitivity Subsystems Design

Abstract

An overview of topics is presented related to noise characterization and modeling of linear, active devices for microwave applications, as well as to advanced methodologies for low-noise design. A complete description of the most common noise measurement techniques, namely the Y-factor method and the cold source method, are provided, with particular attention being paid to practical aspects such as de-embedding the measurement at the device under test reference planes, possible sources of error, and uncertainty estimation. Noise modeling is approached from a well-established standpoint, based on the extraction of a small-signal equivalent circuit model; but also source pull-based techniques—both standard and advanced ones—are broadly illustrated. Finally, a comprehensive discussion on design of single- and multistage low-noise amplifiers is proposed, ranging from the most classical tools and methodologies, such as constant-gain and constant-noise circles, to novel graphical tools and more advanced concepts, such as global mismatch limits and noise measure.