Since the discovery of efficient leaky-wave radiation from a slot in a wave guide by Oliner, leaky-wave antennas have attracted a lot of interest in applications that require beam scanning. Printed planar configurations of LWAs have become very popular, due to low cost. Half-width LWAs based on microstrip lines and substrate-integrated-wave guides have provided an additional advantage of narrow footprint. The problem of scanning through broadside, as solved by Caloz and Itoh uses Composite Right/Left-Handed (CRLH) structures. After briefly reviewing such crucial historical milestones in LWAs, this presentation will focus on recent developments in LWA antenna research and practical outcomes, including some that have the potential to further extend applications of LWAs from current niche scanning applications to mass communication applications such as wireless local area networks and emerging 5G mobile communications.

One of them is fixed-frequency beam steering using only two values of bias voltages, for applications where sweeping the operating frequency is not possible. Several methods of LWA fixed-frequency beam steering has been demonstrated, including one recently developed by the speaker’s team that requires only two bias voltage values to steer the beam. This is very promising for millimetre-wave communication systems such as Wi-Gig and potential millimetre-wave modes of 5G. The principle underlying these LWAs is formation of a multi-state radiating structure by cascading several binary reconfigurable unit cells. Thus the basic building block of the antenna is a reconfigurable binary unit cell, switchable between two states. A macro cell is created by combining several reconfigurable unit cells and the periodic LWA is formed by cascading identical macro cells. Antenna beam is digitally steered in small steps by switching to different macro-cell states. Microwave prototypes based on this concept have demonstrated excellent beam steering over 30 degrees with negligible gain variation (of about 1 dB) and good input matching. As all switches in the antenna are binary, only two bias voltage values are required for beam steering, and the antenna sub-system can be controlled easily using digital electronics. Other recent developments presented in the lecture include (i) steering two side beams simultaneously by sweeping the operating frequency, using the second higher order mode of a microstrip, and (ii) dual-band beam scanning by frequency sweeping, with one beam scanning forward directions and the other one scanning backward directions. At the end, selected topics suitable to future research in this area will be discussed.

Biography, Professor Karu Esselle

Professor Karu Esselle received the BSc degree in electronic and telecommunication engineering with First Class Honours from the University of Moratuwa, Sri Lanka, and MASc and PhD degrees in electrical engineering from the University of Ottawa, Canada. He is a Professor of Electronic Engineering, Macquarie University, Sydney, and Director of WiMed Research Centre.

He is an IEEE Distinguished Lecturer and a Fellow of the IEEE. He is chair of the IEEE New South Wales (NSW) Section, and IEEE NSW AP/MTT Chapter, and is a past member of the IEEE Antennas and Propagation Society Administrative Committee (Ad Comm). He is an Associate Editor of IEEE Transactions on Antennas and Propagation and IEEE Access. He has served his university as an Associate Dean, a member of the Dean’s Advisory Counci, and as Department Head. He is the chair of the Board of management of Australian Antenna Measurement Facility. He directs the Centre for Collaboration in Electromagnetic and Antenna Engineering. He has acted as a consultant for over a dozen companies, including Intel, Hewlett Packard, and Cisco Systems, and has authored almost 500 research publications. His research activities are posted at http://web.science.mq.edu.au/~esselle/

Speaker(s): Karu Esselle,

Location:
Room: EV3.309
Bldg: EV
Concordia University
1515 St Catherine W
Montreal, Quebec
H3G 2W1