1. Electromagnetics Research, University of Nottingham, Nottingham, U.K.
2. Postdoctoral Researcher, Aristotle University of Thessaloniki, Thessaloniki, Greece
3. Institute of Electronic Structure and Laser, Foundation for Research and Technology Hellas, Heraklion, Greece
4. School of Electrical and Computer Engineering, Aristotle University of Thessaloniki, Thessaloniki, Greece
5. Full Professor, Universitat Politècnica de Catalunya, Barcelona, Spain
6. Associate Professor, Universitat Politècnica de Catalunya, Barcelona, Spain
7. Universitat Politècnica de Catalunya, Barcelona, Spain