stefano maci

Reflective Intelligent Surfaces and Metasurface Antennas

The new paradigm of smart radio environment (SRE) is discussed in this talk from the perspective of metasurface-based intelligent surfaces (IS) is categorized here by using the synthetic notation RIS-n, where n counts the number of “R”-type functionalities embedded in the IS: Reflecting IS (RIS-1), Reflecting-Reconfigurable IS (RIS-2) Receiving-Repeating-Reconfigurable IS (RIS-3), Receiving-Regenerating-Repeating-Reconfigurable IS (RIS-4). For increasing n, RIS-n possess an increasing level of complexity, environmental impact, power consumption and costs, but a decreasing level of densification and standardization requirement. The deployment of RIS-n in SRE is reviewed considering the new challenges that the RIS-n technology implies when implemented through metasurfaces. Special emphasis is given to efficient ray-model for both Fresnel and far zone coverage, where the scattered field from polygonal contoured RIS-1 or RIS-2 is represented in terms of few rays. The latter formulation can be conveniently used in a ray-tracer to speed-up dramatically the calculation of the field coverage. All types of RIS are well suited to be implemented by metasurface technology, that have now reached a maturity for reconfigurable low-cost antenna implementations. Examples of RIS-1, RIS-2 and RIS-3 will be discussed.

Stefano MACI is a Professor at the University of Siena since 97. His research interest includes high-frequency and beam representation methods, computational electromagnetics, large phased arrays, planar antennas, reflector antennas and feeds, metamaterials and metasurfaces. Since 2000, he was member the Technical Advisory Board of 13 international conferences and member of the Review Board of 6 International Journals. In 2004 he was the founder of the European School of Antennas (ESoA), a post graduate school that presently comprises 34 courses on Antennas, Propagation, Electromagnetic Theory, and Computational Electromagnetics and 150 teachers coming from 15 countries. Since 2004 is the Director of ESoA. Since 2010 he has been Principal Investigator of 6 cooperative projects financed by European Space Agency. Professor Maci has been a former member of the AdCom of IEEE Antennas and Propagation Society (AP-S), associate editor of AP-Transaction, Chair of the Award Committee of IEEE AP-S, and member of the Board of Directors of the European Association on Antennas and Propagation (EurAAP). From 2008 to 2015 he has been Director of the PhD program in Information Engineering and Mathematics of University of Siena, and from 2013 to 2015 he was member of the first National Italian Committee for Qualification to Professor. He has been former member of the Antennas and Propagation Executive Board of the Institution of Engineering and Technology (IET, UK). He founded and has been former Director of the consortium FORESEEN, involving 48 European Institutions. He was the principal investigator of the Future Emerging Technology project “Nanoarchitectronics” of the 8th EU Framework program, and he is presently principal investigator of the EU program “Metamask”. He was co-founder of 2 Spin-off Companies. He has been a Distinguished Lecturer of the IEEE Antennas and Propagation Society (AP-S), and EuRAAP distinguished lecturer in the ambassador program. He was recipient of the EurAAP Award in 2014, of the IEEE Schelkunoff Transaction Prize in 2016, of the Chen-To Tai Distinguished Educator award in 2016, and of the URSI Dellinger Gold Medal in 2020. He has been TPC Chair of the METAMATERIAL 2020 conference and designed Chairperson of EuCAP 2023. In the last ten years he has been invited 25 times as key-note speaker in international conferences. He is the President of the IEEE Antennas and Propagation Society in 2023. His research activity is documented in 200 papers published in international journals, (among which 100 on IEEE journals), 10 book chapters, and about 500 papers in proceedings of international conferences. His papers have been cited about 10,000 times.