Stephan Frei studied electrical engineering in Saarbrücken and Berlin, specialising in theoretical electrical engineering. In 1995, he received his diploma from the Technical University of Berlin. He also earned his doctorate there in 1999.

From 1995 to 1999 he worked as a research assistant at the Institute for Electrical Power Engineering at the TU Berlin. There he worked on simulation methods for electromagnetic compatibility and electrostatic discharges, among other things. In 1999, he joined Audi AG in Ingolstadt. In the department of electronics for complete vehicles, he worked in the area of EMC and antenna development and was responsible for various pre-development and simulation topics as a project manager. Since 2006, Mr Frei has been a professor at the Technical University of Dortmund and heads the on-board systems department, where he and his group work on current issues relating to the simulation of electrical vehicle components. The vehicle electrical system plays a special role here and is considered in its capacity as a transmission medium for energy and data. New methods for field and network-based simulation as well as parameter determination are being developed in this area. Thermal problems, signal integrity and EMC/ESD issues are an important focus. From 2008 to 2009, Mr Frei was Distinguished Lecturer for the IEEE EMC Society. He is author or co-author of more than 150 scientific publications and active in various national and international standardisation groups. Mr Frei has been Dean of the Faculty of Electrical Engineering and Information Technology at TU Dortmund University since 2014.