Reconfigurable Antennas: Architectures, Technologies, and Their Exciting Future

Prof. Sean Hum

The Edward S. Rogers Sr. Department of Electrical and Computer Engineering (Electromagnetics)

Abstract:

Life without wireless communications today seems unimaginable, as new applications for radio systems and devices continue to abound. Antennas are one of the key enabling components of this technology, and the demands of modern wireless communication systems require engineers to re-think the design of these devices to conform to evolving expectations in terms of electrical specifications, size, cost, functionality, and increasingly, adaptability.  Exciting innovations in reconfigurable antennas promise to enable these components to contend with this new reality. Reconfigurable antennas possess the ability to electronically reconfigure their radiating and electrical characteristics, including their radiation pattern, polarization, and/or frequency of operation.  This adaptability is made possible by the incorporation of electronically-tunable circuit components, such as active and micro-electro-mechanical-systems (MEMS components) into an antenna's structure.  These "field-programmable" antennas are adding new dimensions to wireless system capabilities, enabling them to adapt to movement, adjust to changing channel conditions, perform beam scanning, or even change their configurations entirely for software-defined radio applications.

This presentation will discuss the design and analysis of several reconfigurable antenna types.  First, the talk will begin by presenting frequency-agile antennas, which can be programmed to radiate over a very wide range of user-defined frequencies.  Second, a  class of pattern-reconfigurable antennas based on reconfigurable apertures will be discussed.  Such antennas enable high-gain adaptive beamforming to be achieved in a wireless system with a much lower hardware cost than traditional systems such as phased antenna arrays.  Specifically, electronically-tuned reflectarrays achieve large antenna gains while enabling the antenna beam to be scanned over a sizeable angular range.  They are also amenable to integration with active components, enabling low-cost power amplification to be achieved in a distributed structure.  In a similar manner, reconfigurable lenses allow low-cost beamforming to be achieved in planar and conformal structures, with the latter potentially enabling the antenna beam to be scanned over a much wider range than that possible with reflector antennas.  Finally, compact planar implementations of reconfigurable leaky-wave antennas will be presented.

The talk will present both a theoretical and experimental exploration of reconfigurable antennas.  Theoretical insights into these unique antennas can be achieved using equivalent circuit modelling techniques and simple electromagnetic principles.  Their capabilities will be highlighted by reviewing some recent experimental achievements with various antenna designs.  Exciting applications for these antennas in communications, RADAR, remote-sensing, and multi-input multi-output (MIMO) systems will be highlighted.  

Finally, some perspectives on academic career planning will be shared.

Biography:

Sean Victor Hum was born in Calgary, Alberta, Canada.  He received his B.Sc., M.Sc. and Ph.D. degrees from the University of Calgary in 1999, 2001, and 2006 respectively.  In 2006 he joined the Edward S. Rogers Sr. Department of Electrical and Computer Engineering at the University of Toronto where he currently serves as an assistant professor.  Prof. Hum leads the reconfigurable antenna laboratory at the UofT, and along with his students, he is conducting research in the areas of reflectarrays, reconfigurable RF antennas and systems, antenna arrays, and antennas for space applications.  Prof. Hum received the Governor General's Gold Medal for his master's degree work on radio-on-fiber systems in 2001.  In 2004 he received an IEEE Antennas and Propagation Society Student Paper award for his work on tunable reflectarrays.  In 2006, he received an ASTech Leaders of Tomorrow award for his work in this area. On the teaching side, Prof. Hum has received three UofT Departmental Teaching Award since 2007, and most recently, an Early Career Teaching Award in 2011.  He received the Gordon Slemon Award for the Teaching of Design in 2011.  Prof. Hum is a senior member of the IEEE and a member of URSI (the International Union of Radio Science), and an Associate Editor of the IEEE Transactions on Antennas and Propagation.