Microwave Network Analysis

This chapter defines scattering (S) parameters in relation to impedance and admittance parameters, and demonstrates the use of S parameters in the design and interpretation of RF circuits. S parameters have become the most important parameters for RF and microwave engineers, and many design methodologies have been developed around them. Single transmission lines are two‐port networks having four terminals, with one port at each end of the line comprising a signal terminal and a reference terminal. The two reference terminals are required as it is not possible to define a global ground that is common to the two ends of a transmission line. Signal‐flow graphs form a logical and convenient means for analysing microwave circuits of virtually any form and complexity, provided only that they can be treated as linear and S parameters are applicable. Typical problems requiring this kind of analysis include measurement error assessment and amplifier gain calculations.