Non-Diffractive Radiation and Near-Field Focusing Techniques

The talk will focus on the generation of non-diffractive radiation at micro- and millimeter-waves with planar radiating structures. The concept of non-diffractive radiation will be introduced with a special attention to Bessel and Hankel beams. The non-diffractive behavior of such beams makes them very attractive for a wide range of applications in engineering and optics. This presentation will describe our recent achievements in the generation of non-diffractive beams with planar radiating structures made by metasurfaces and radial line slot arrays using leaky-wave modes and inward cylindrical traveling waves. Different launchers with various field polarizations and band capabilities will be presented. The generation of X-waves will be then introduced and their practical implementation discussed. In particular, a wideband circular polarized radial line slot array is proposed to generate X-waves at millimeter waves in a defined space range.

We will introduce as well our recent developed tool for near-field shaping over 2D and 3D space regions. The tool allows an "almost" arbitrary control of the near field of planar radiating structures for enhanced focusing capabilities and field shaping. The aperture field distribution generated by the near-field shaping tool is automatically synthetized by using an in-house efficient optimization algorithm for radial line slot arrays. Several examples will be presented aiming at tailoring the depth of focus and field profile of the generated near field in defined planes and volumes over the radiating aperture.

Dr. Mauro Ettorre was born in Tricarico, Matera, Italy. He received a laurea degree summa cum laude in electrical engineering and a Ph.D. in electromagnetics from the University of Siena, Italy, in 2004 and 2008, respectively. During his Master's degree studies, he spent five months at the Technical University of Denmark (DTU), Lyngby, Denmark. Part of his Ph.D. work was developed at the Defence, Security and Safety Institute of the Netherlands Organization for Applied Scientific Research (TNO), The Hague, Netherlands, where he later worked as an antenna researcher. From 2008 to 2010, Dr. Ettorre was a Postdoctoral Fellow at the Institut d'electronique et de Télécommunications de Rennes (IETR), Université de Rennes 1, France. In 2010, he was a Visiting Scholar at the Radiation Laboratory, Department of Electrical Engineering and Computer Science, University of Michigan. Since October 2010, he is a Research Scientist at the French National Center for Scientific Research (CNRS), within a unit of IETR. Dr. Ettorre's research interests include the analysis and design of leaky-wave antennas, periodic structures, millimeter-wave antennas, non-diffractive radiation, near-field focusing techniques, and wireless power transfer systems. He has authored over 90 journal and conference papers and has 5 international patents on millimeter-wave antenna technology. Dr. Ettorre received the Young Antenna Engineer Prize at the 2008 European Space Agency Antenna Workshop in Noordwijk, Netherlands and a French Ministry of Research award for the most innovative project in all natural sciences in Brittany, in 2009. As a Ph.D. student, he also received two internal projects/awards for innovative and original ideas at TNO in 2006 and 2007.