Distinguished Prof. Yahya Rahmat-Samii delivered an hour long conference keynote speech entitled, “The Marvels of Periodic Structures in Modern Electromagnetics and Antennas: A New Look at FSS, EBG, Reflectarrays and Nano-Pillars” at the 2017 ACES (Applied Computational Electromagnetics Society) in Florence, Italy, March 25-31, 2017. This conference, which is held every year in different parts of the world, covers all aspects of advanced electromagnetic computational techniques and antenna designs. Prof. Rahmat-Samii was previously elected the Fellow of this international society in 2012.