HD-04: Advanced impedance matching and impedance analysis for antenna applications

Jussi Rahola

Sunday, July 19, 13:00 - 17:00


The course is targeted for antenna and RF engineers and researchers who study new antenna concepts and who need to use matching circuits in their work. It reviews the definitions of the reflection coefficient, S and Z parameters (also in the multiport case) and the Smith chart so that the course can be used as theory refresher for all antenna engineers. It is also explaining the theory of power waves, which makes the understanding of impedance matching to complex generator impedances easier. The course will present some novel views on matching circuit design. For example it will be demonstrated that the goal of matching circuit design using realistic component models is to obtain best possible transfer of power, and thus not to obtain the best possible impedance match, which may seem paradoxical at first. Simultaneous multiport matching and the design of tunable matching networks will be discussed. Tools for estimating the obtainable bandwidth and worst-case isolation for non-resonant antennas will be discussed. Overall, the course will cover the theory and practical aspects of matching circuit design and impedance analysis and it offers new information to both beginners and more senior antenna and RF experts.


Jussi RAHOLA obtained the M.Sc. (Tech.) and D.Sc. (Tech.) degrees in applied mathematics from Aalto University (former Helsinki University of Technology) in 1990, and 1996, respectively. The topic of his dissertation was the solution of large dense systems of linear equations of electromagnetics using iterative solvers and the fast multipole method. From 1989 to 1999 he was working as an application specialist and a development manager in CSC - IT Center for Science Ltd, Finland. During 1997-1998 he also worked in CERFACS, Toulouse, France as a post-doctoral researcher in the field of computational electromagnetics. From 2000 to 2009 he worked in Nokia Research Center and Nokia Devices R&D as a senior research engineer, research manager and principal scientist in the field of antenna research. In 2009 he founded Optenni Ltd for developing the Optenni Lab impedance analysis software. He has over 30 publications in international journals and conference proceedings. His research interests include antennas, circuit simulation, impedance matching, computational electromagnetics and numerical mathematics.