Title of the talk:
" WIDEBAND ARRAYS WITH BEAMFORMING "
Professor John L. Volakis
Professor and Dean, Florida International University
Future wireless communication systems will require much higher data rates. Suhc high rates require wideband arrays with beam forming capabilities. Concurrently, the RF spectrum will become more vulnerable due to intentional and unintentional interference. Therefore, interference cancellation and mitigation techniques as well as low cost wideband beamformers are required to ensure high gain secure communication for 5G commercial applications and for government needs.
Conventional interference suppression techniques are based on fixed or adaptive filtering and are limited in terms of their spectral and spatial filtering. That is, in presence of high interference levels, these techniques fall short to achieving enough suppression. Also, most interference suppression techniques require previous knowledge of the interferer’s position, channel, and signal identity.
In realistic scenarios, and when communicating across wide bandwidths, interferers are unknown. Therefore, more advanced techniques are required to suppress interference. Concurrently, with the goal to utilize additional bandwidth, a well-known technique is to enable Simultaneous Transmit and Receive (STAR). STAR offers the advantage of reusing the transmit/receive bands, and therefore double throughput via a method referred to as full duplexing. However, implementation of STAR requires significant isolation between transmit and receive signals. As much as -90dB and even -120dB of isolation between transmit and receive signals is required. To do so, we must 1) cancel interference caused by the transmitter itself (as the receiver is typically collated with the receiver), 2) remove multipath transmitted signals, 3) suppress harmonics from power amplifiers (PAs), and 4) cancel noise from the transmit chain. From the literature, earlier versions of STAR architectures are narrowband, and therefore not useful for wideband communications systems.
To address the abovementioned challenges, we discuss a new class of wideband antennas and RF back-ends, a large bandwidth of 10GHz to be contiguously accessed. Specifically, this presentation will discuss: 1) ultra-wideband (UWB) phased array with low angle scanning, bandwidth reconfiguration, and controllable band rejection, 2) broadband digital beamformer with reduced power requirements using a much smaller number of analog-to-digital converters (ADCs) with power and cost reduction by a factor of 8 to 32, 3) novel hybrid frequency and code division multiplexing (CDM) with channel coding for secure high data rate communications to cover a contiguous 10GHz bandwidth with up to 40dB of additional gain and interference mitigation, and 4) wideband STAR implementation using four stages of cancellation to realize >120dB reduction in self-interference across a bandwidth >1 GH.
Professor John L. Volakis (S’77–M’82–SM’89–F96) was born in Chios, Greece, on May 13, 1956 and immigrated to the USA in 1973. He received the B.E. degree (summa cum laude) from Youngstown State University, Youngstown, OH and the M.Sc. and Ph.D. degrees from The Ohio State University, Columbus, in 1979 and 1982, respectively. He started his career at Rockwell International (1982–1984), now Boeing Phantom Works. In 1984, he was appointed Assistant Professor at the University of Michigan, Ann Arbor, becoming a full Professor in 1994. He also served as the Director of the Radiation Laboratory from 1998 to 2000. From Jan. 2003- Aug. 2017, he was the Roy and Lois Chope Chair Professor of Engineering at The Ohio State University and also served as the Director of the ElectroScience Laboratory (2003-2016). Since Aug . 2017, he is a Professor and Dean of Engineering and Computing at Florida International Univ. During his 35 years career, he has carried out research on antennas, medical sensing, computational methods, electromagnetic compatibility and interference, propagation, design optimization, RF materials and metamaterials, RFIDs, millimeter waves and terahertz, body-worn wireless technologies, and multi-physics engineering. His publications include 8 the books. Among them are: Approximate Boundary Conditions in Electromagnetics (IET, 1995), Finite Element Methods for Electromagnetics (Wiley–IEEE Press, 1998) the classic 4th ed. Antenna Engineering Handbook (McGraw–Hill, 2007), Small Antennas (McGraw–Hill, 2010), and Integral Equation Methods for Electromagnetics (SciTech, 2011)]. His papers include over 400 journal papers, nearly 800 conference papers, and 25 book chapters. He has also written several well-edited coursepacks, and has delivered short courses on antennas, numerical methods, and frequency selective surfaces.
2016: Ohio State Univ. Distinguished Scholar Award, top award given by Ohio State to a faculty member. Award video: https://www.youtube.com/watch?v=yeZOvrSp-Pw
2016: Ohio State Univ. George Sinclair Award for “excellence in research, and his exemplary leadership of the ElectroScience Laboratory, including establishing new research areas in electromagnetic sensor technologies and securing a new ESL building.”
2014: IEEE Antennas and Propagation Society Distinguished Award, 2014 (given to one individual annually from across the world). Award citation: “For game-changing contributions to computational electromagnetics, radar scattering and antennas, and for educational leadership and service to the electromagnetics community.”
2013: IEEE Rudolf Henning Distinguished Mentoring Award, 2013 (given to one individual annually)
2011: Fellow, Applied Computational Electromagnetics Society.
2011: IEEE Chen-To Tai Distinguished Education Award (given to one individual annually. Citation: For exemplary contributions as an inspiring teacher and mentor, and for advancing electromagnetic technology.
2010: Scott College of Engineering career award for teaching research and service, Ohio State Univ. Citation: For pioneering contributions in education, including authorship of important texts and excellent mentoring of students, in research, including seminal contributions to computational electromagnetics and antenna design, and for leadership and distinctive service to the engineering profession.
2006-2010: IEEE Distinguished Lecturer
2004: Listed by ISI among the top 250 most referenced authors
1996: Fellow of Institute of Electrical and Electronics Engineers (IEEE)