Understanding Transmission Line Impedance Matching Using Neural Networks and PowerPoint

Abstract – Impedance matching between transmission lines and antennas is an important and fundamental concept in electromagnetic theory. It is frequently performed with Smith charts or relatively complex formulas, but mathematical methods can yield unanticipated results unless the student has a solid grasp of the underlying theory. Unfortunately, students rarely show interest in graphical techniques and Smith charts can be difficult to use because of optical effects generated by the gridlines. This paper presents an alternative method of teaching single stub impedance matching by permitting students to verify their results from the Smith chart with a neural network. This technology provides instant feedback for most single stub problems, and is re-enforced through web-based PowerPoint demonstrations. The neural network presents the solution, not the procedure, so it is the responsibility of the student to seek help from the instructor or use the PowerPoint tutorial. Student comments have been very positive, and course evaluations have improved. Index Terms – Transmission line impedance matching, neura