The Department of Electrical Engineering at the Syed Babar Ali School of Science and Engineering (SBASSE) held the 12th Teaching the Teachers workshop on “S-parameters: Theory and Uses to Characterise Circuits” on December 26, 2019.
Scattering (“s”) parameters are used in many branches of electrical engineering. At radio and microwave frequencies, they are the exclusive way to characterise circuits. But they are also used at low frequencies, in filter design and in measurements using network analysers. All electrical engineers should be familiar with the use of s-parameters, even for application at low frequencies. S-parameters give exclusive insights into power flow, although they are equally useful to characterise voltages and currents.
The workshop was conducted by Professor Asad Ali Abidi. He received a BSc degree in Electrical Engineering from Imperial College, London in 1976, and a PhD from the University of California, Berkeley in 1982. He worked at Bell Laboratories, Murray Hill until 1985, and then joined the faculty of the University of California, Los Angeles where he is the Distinguished Chancellor’s Professor of Electrical Engineering.
The workshop covered the following topics:
• Available power from a source, and a derivation of reflection coefficient from first principles
• Bilinear transformation and the Smith Chart
• Scattering parameters for resistively terminated 2 ports, and N ports
• Examples of uses of the Smith Chart
• Visualisation of s-parameters with signal flow graphs
• Examples of uses of s-parameters and the insights they give on various circuits
• Network analyser instruments: architectures and method of operation
The sessions were a success, and participants appreciated the skills, tools and techniques they learnt to improve their teaching skills.
