Prof. Ioannis Tigelis Ioannis G. Tigelis was born in Lamia, Greece in 1964. He received the Diploma and the Ph.D. degree in Electrical Engineering from the National Technical University of Athens in 1986 and 1990, respectively. Since 1992 he is with the National and Kapodistrian University of Athens, Department of Physics, where he is now Professor. His current interests include electromagnetic wave propagation in complex waveguide structures, interaction between electromagnetic waves and electron beams, numerical methods in electromagnetics. He has authored or co-authored more than 130 journal and conference papers and many technical reports, while he has participated in more than 20 European and national research projects.