Prof Christophe Caloz of École Polytechnique of Montréal

Leaky-wave antennas (LWAs) have a history of over 70 years. This history started with a patent on a leaky slit waveguide by Hansen in 1940, and the field was then really developed in the late 1950ies and 1960ies by the Brooklyn Polytechnic (now NYU Poly) microwave group, involving Oliner, Tamir and Hessel. Since then, much LWA research has then been carried out by various groups around the world. However, despite some of their unique features, LWAs have been plagued by fundamental issues that have limited their utilization in practical systems. These issues have been recently solved, bringing us to the doorstep of a new area in LAWs.

The unique benefits of LWAs is that they provide high directivity and (frequency or electronic) beam scanning with much smaller form factor, lower cost and higher gain than antenna arrays, as they do not require a complex feeding network. In uniform LWAs, these benefits are annihilated by the restriction of forward-only scanning. Periodic LWAs have been capable of radiating both in forward and backward directions, using leaky space harmonics, since their introduction by Rotman in the late 1950ies. However, their aforementioned LWA benefits have been countered by the collapse of the radiation efficiency at broadside. A definite solution to this persistent issue came in 2002 with the advent of metamaterial Composite Right/Left-Handed (CRLH) LWAs, the first LWAs capable of efficient full-space scanning, which made LWAs potentially superior to arrays. The secrets for this long sought solution were revealed by the groups of D. R. Jackson and of the speaker over the past decade, and then extended to non-metamaterial LWAs: 1) presence of two resonators in the unit cell, 2) closure of the open-stop band by mutual cancellation of the two resonances, 3) satisfaction of a Heaviside-like condition to equalize gain through broadside. Moreover, fundamental relations between the (transverse and longitudinal) symmetries of the periodic unit cell and the LWA properties were recently unveiled by the speaker and collaborators at the University of Duisburg, providing prescriptions completing the broadside radiation ones for most efficient and diverse LWA designs. The talk first overviews historical milestones, explains the physics of LWAs (including their fundamental connection with the Smith-Purcell effect in particle physics) and provides basic electromagnetic tools for their analysis. Next, it presents and illustrates the solution to the broadside radiation issue as well as the unit cell symmetry rules. Finally, it demonstrates a number of novel concepts, structures, systems and applications, including active LWA beam forming, gain enhancement via power recycling, LWA direction-of-arrival estimation, non-reciprocal LWA diplexers, direction diversity enhanced MIMO systems, smart reflectors, graphene-tunable THz antennas, real-time spectrogram analyzers, and vortex beam launchers for orbital angular momentum multiplexing.

Biography:

Christophe Caloz received the Diplôme d'Ingénieur en Électricité and the Ph.D. degree from École Polytechnique Fédérale de Lausanne (EPFL), Switzerland, in 1995 and 2000, respectively. From 2001 to 2004, he was a Postdoctoral Research Fellow at the Microwave Electronics Laboratory, University of California at Los Angeles (UCLA). In June 2004, Dr. Caloz joined École Polytechnique of Montréal, where he is now a Full Professor, the holder of a Canada Research Chair (CRC) Tier-I and the head of the Electromagnetics Research Group. He has authored and co-authored over 600 technical conference, letter and journal papers, 13 books and book chapters, and he holds several patents. His works have generated about 15,000 citations, and he is a Thomson Reuters Highly Cited Researcher. Dr. Caloz was a Member of the Microwave Theory and Techniques Society (MTT-S) Technical Committees MTT-15 (Microwave Field Theory) and MTT-25 (RF Nanotechnology), a Speaker of the MTT-15 Speaker Bureau, the Chair of the Commission D (Electronics and Photonics) of the Canadian Union de Radio Science Internationale (URSI) and an MTT-S representative at the IEEE Nanotechnology Council (NTC). He co-founded the company ScisWave in 2009 and the company WaveInt in 2015. Dr. Caloz received several awards, including the UCLA Chancellor’s Award for Post-doctoral Research in 2004, the MTT-S Outstanding Young Engineer Award in 2007, the E.W.R. Steacie Memorial Fellowship in 2013, the Prix Urgel-Archambault in 2013, and many best paper awards with his students at international conferences. He has been an IEEE Fellow since 2010 and an IEEE Distinguished Lecturer for the Antennas and Propagation Society (AP-S) since 2014. Since June 2015, he has been an Associate Editor of the Transactions on Antennas and Propagation of AP-S. In 2014, Dr. Caloz was elected as a member of the Administrative Committee of AP-S. He is currently also a Distinguished Adjunct Professor at King Abdulaziz University (KAU), Saudi Arabia. His research interests include all fields of theoretical, computational and technological electromagnetics, with strong emphasis on emergent and multidisciplinary topics, including particularly metamaterials, nanoelectromagnetics, exotic antenna systems and real-time radio.

Address:Poly-Grames Research Center, École Polytechnique of Montréal, Montréal, Quebec, Canada

Prof Christophe Caloz of École Polytechnique of Montréal

Biography:

Address:Montréal, Quebec, Canada