3.1: Introduction

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The network parameters that directly describe reflected and transmitted power flow in circuits are scattering (\(S\)) parameters. This chapter introduces two widely used graphical techniques for describing and solving problems using \(S\) parameters. The first graphical technique is signal flow graph analysis (SFG) and is a graphical way of representing equations and variables. Simplifying an SFG is the same as solving simultaneous equations and the equations can be kept in symbolic form. The second graphical representation is an annotated polar plot of \(S\) parameters called a Smith chart. This is one of the most powerful tools in RF and microwave engineering and is used to present measured results, to conceptualize designs, and to intuitively solve problems involving distributed networks.