He received the Dipl. Phys. and Dr. rer. nat. degrees in physics from University of Tubingen, Germany, in 1972 and 1976, respectively. At the University of T ̈ ubingen he was involved in the investigation of spin-dependent nuclear forces in inelastic neutron scattering. From 1972 to 1975 he was Doctoral Fellow of the Studienstiftung des Deutschen Volkes. In 1976 he joined the Institute for Plasma Research in the Electrical Engineering Department of the University of Stuttgart, Germany, where he worked on RF production and RF heating of toroidal pinch plasmas for thermonuclear fusion research. From 1982 to 1990 his research activities were mainly devoted to electromagnetic theory in the areas of component development for the transmission of very high power millimeter waves through overmoded waveguides and of antenna structures for RF plasma heating with microwaves. In June 1990 he became a Full Professor of the Institute for High-Frequency Techniques and Electronics at the University of Karlsruhe, Germany, and Head of the Gyrotron Development and Microwave Technology Division, Institute for Technical Physics, Research Center Karlsruhe, Forschungszentrum Karlsruhe (FZK). Since April 1999, he has been the Director of the Institute for Pulsed Power and Microwave Technology at FZK, where his current research projects are the development of high power gyrotrons, dielectric vacuum windows, transmission lines and antennas for nuclear fusion plasma heating, and industrial materials processing. He has authored/coauthored three books, 9 book chapters, 180 research papers in scientific journals, and approx. 800 conference proceedings articles. He holds 10 patents on active and passive microwave devices. He is vice chairman of Chapter 8.6 (Vacuum Electronics and Displays) of the Information Technical Society in German VDE and a member of the German Physical Society. In 2006 he has been appointed to be a member of the IEEE EDS Vacuum Devices Technical Committee. He has been awarded with the Kenneth John Button Medal and Prize 2000, in recognition of outstanding contributions to the Science of the Electromagnetic Spectrum. In 2002, he was awarded the title of Honorary Doctor, presented by the St. Petersburg State Technical University, for his outstanding contributions to the development and applications of vacuum electron devices.