Presentation of the Smith Chart and Applications to Analog Circuit Analysis

The paper presents the Smith chart as the most used visual method for RF circuits. Smith chart gives an intelligent approach to represent complex functions. The basic concepts that enable the Smith chart to be applied in the analysis, synthesis, and design of analog RF circuits are presented. It is shown that the Smith chart is a simple method to represent not only impedances and admittances in the complex plane, but also reflection coefficients in the polar plane (amplitude and phase). It also allows drawing constant Q circles, constant Standing Wave Ratio (SWR) or even stability circles. It is shown that the Smith chart not only eliminates a substantial amount of computation, but also allows for a very intuitive visual representation of impedances and admittances. Although the graphical use of this diagram does not provide accurate calculations, the intuitive form of the results and the ease with which some impedances can be adapted, substantially eases the design work.