Northern Canada AP/MTT Jt. Chapter

IEEE
April 24th, 2017

The IEEE Northern Canada Section Antennas & Propagation Society and the Microwave Theory & Techniques Society (IEEE NCS APS/MTTS) joint chapter would like to invite you to attend the next installment of our invited talks.  Professor Lotfollah Shafai from the University of Manitoba will be giving a presentation titled “Challenges of Antenna Miniaturization“.

Where:

ICE 8-207, University of Alberta

When:

01-May-2017 01:00PM to 2:00PM

Abstract

Wireless communication is becoming an essential part of almost all new technologies, especially in personal communication, remote sensing, autonomous navigation, medical imaging and structural or personal health monitoring, to name a few. Since the dominant means of information exchange is electromagnetic waves, they need antennas to transmit and receive the waves and electronics to process them. However, antennas must interface two separate bounded and unbounded media, where waves have distinct and different sizes. Consequently, to interact efficiently with waves their dimensions have become wavelength dependent, limiting their size reductions. This is the major impediment for antenna miniaturization. On the other hand, advancement of traditional technologies and emergence of new ones require ongoing size reductions to incorporate more features and operate at lower cost. This size discrepancy, thus, has made antennas the “Achilles’ heel” of technology progress, and is not limited to any particular area. Any small reduction in the antenna size, without deteriorating their performance, will provide a major progress in related technologies. This presentation will address planar antennas, and highlight the penalties paid for their miniaturization using traditional design methods, and provide examples of new design techniques that can overcome them.

Biography

Lotfollah Shafai B.Sc. from University of Tehran in 1963 and M.Sc. and Ph.D., from University of Toronto, in 1966 and 1969. In November 1969, he joined the Department of Electrical and Computer Engineering, University of Manitoba as a Lecturer, Assistant Professor 1970, Associate Professor 1973, Professor 1979, and Distinguished Professor 2002, and Distinguished Professor Emeritus 2016. His assistance to industry was instrumental in establishing an Industrial Research Chair in Applied Electromagnetics at the University of Manitoba in 1989, which he held until July 1994.
In 1986, he established the symposium on Antenna Technology and Applied Electromagnetics, ANTEM, at the University of Manitoba, which has grown to be the premier Canadian conference in Antenna technology and related topics.
He has been the recipient of numerous awards. In 1978, his contribution to the design of the first miniaturized satellite terminal for the Hermes satellite was selected as the Meritorious Industrial Design. In 1984, he received the Professional Engineers Merit Award and in 1985, “The Thinker” Award from Canadian Patents and Development Corporation. From the University of Manitoba, he received the “Research Awards” in 1983, 1987, and 1989, the Outreach Award in 1987 and the Sigma Xi Senior Scientist Award in 1989. In 1990 he received the Maxwell Premium Award from IEE (London) and in 1993 and 1994 the Distinguished Achievement Awards from Corporate Higher Education Forum. In 1998 he received the Winnipeg RH Institute Foundation Medal for Excellence in Research. In 1999 and 2000 he received the University of Manitoba Research Award. He is a life Fellow of IEEE and a life Fellow of The Royal Society of Canada. He was a recipient of the IEEE Third Millenium Medal in 2000 and in 2002 was elected a Fellow of The Canadian Academy of Engineering. In 2003 he received the IEEE Canada “Reginald A. Fessenden Medal” for “Outstanding Contributions to Telecommunications and Satellite Communications”, and a Natural Sciences and Engineering Research Council (NSERC) Synergy Award for “Development of Advanced Satellite and Wireless Antennas”. He held a Canada Research Chair in Applied Electromagnetics from 2001 to 2015, and was the International Chair of Commission B of the International Union of Radio Science (URSI) for 2005-2008. In 2009 he was elected a Fellow of the Engineering Institute of Canada, and was the recipient of IEEE Chen-To-Tai Distinguished Educator Award. In 2011 he received the Killam Prize in Engineering from The Canada Council, for his “outstanding Canadian career achievements in engineering, and his research on antennas”. In 2013 he received The “John Kraus antenna Award” from IEEE Antennas and Propagation Society “For contributions to the design and understanding of small high efficiency feeds and terminals, wideband planar antennas, low loss conductors, and virtual array antennas”. In 3014 he was the recipient of Edward E. Altshuler Best paper Prize from IEEE APS Magazine. His students have received numerous Best paper awards from IEEE, and young scientist awards from URSI.


March 23rd, 2017

We are pleased to announce the first session in our student seminar series 2017. Two of our students will be presenting on  WednesdayMarch 29 from 12:00 pm – 1:00 pm in ICE 8-207. 

Speaker #1: David Sawyer – “Choke Ring Structures for Ground Penetrating Radar


Background: Ground penetrating radar (GPR) is a mature and successful technology that replaces expensive excavation and prospecting with simple scanning and imaging. Due to the high degree of loss in the ground at microwave frequencies, GPR systems are extremely susceptible stray reflections and interference (known as clutter), which can overwhelm signals of interest. For common GPR antennas such as dipoles, shielding, such as with a metallic cavity, is an attractive way to isolate the antenna from the above-ground environment. However, currents induced on the shield by the antenna can travel around the shield and re-radiate, acting as a source of clutter and offsetting these benefits. Choke rings are a well-known structure used for global positioning systems that reduce multi-path interference that work by suppressing currents along a plane. This work presents choke-ring structures as a way to suppress these currents for GPR and demonstrates that good bandwidth and time-domain performance may be achieved through the use of resistive, rather than perfectly metallic structures.

Biography: David Sawyer graduated from the University of Alberta with a B.Sc. in engineering physics in 2015, and as of 2017 is currently in the process of his M.Sc. in the area of microwave circuits. His current work is involved in the areas of metamaterial surfaces, small antennas, and ground penetrating radar, considering both frequency and time domain results. His work in this area has recently been accepted for publication at the AP-S Symposium on Antennas and Propagation. Some of David’s interests include fundamental limitations in electromagnetics, as well as numerical and mathematical methods in electromagnetics. David’s interests also extend to the arts. He currently helps run the University of Alberta Mixed Chorus as part of their executive, and is also a member of a local dance performance team.

Speaker #2: Mitchell Semple – “Optical Implementation of a Miniaturized ENNZ-Metamaterial-Lined Aperture Array


 

Abstract: Aperture arrays have been used as frequency selective surfaces and to demonstrate extraordinary transmission, and have been proposed for a multitude of applications. The operation of these devices requires large areas as they depend on either aperture size or array periodicity, respectively, on the order of a wavelength. It has recently been demonstrated that lining each circular aperture in an array with a thin epsilon-negative and near-zero (ENNZ) metamaterial dramatically lowers its resonance frequency while the aperture itself remains largely empty, obviating the need for both large apertures and large aperture spacing. Thus, aperture-array-based devices could be miniaturized in the microwave regime (E. Baladi, J. G. Pollock, and A. K. Iyer, Opt. Express, vol. 23, no. 16, 2015).
An optical implementation of the ENNZ-metamaterial-lined aperture array, simulated using COMSOL Multiphysics, will be presented. Challenges in achieving an optical implementation included the reliance of the microwave design on lumped circuit elements and near-ideal conductor properties, which cannot be reproduced directly at optical frequencies. The proposed optical aperture array was designed to improve transmission at optical-telecommunications wavelengths of λ = 1.55 μm (f = 193 THz) through apertures of size λ/5 and spacing λ/4. For a patterned gold surface with minimum feature size of 10 nm, an 8.7 dB transmission improvement over the unlined case was realized.

Biography: Mitchell graduated from the University of Alberta in 2016 with a B.Sc. in Electrical Engineering. He has previously worked on integrating molecular junctions into guitar distortion pedals as amplifier feedback elements and is currently an M.Sc. student working on plasmonic metamaterials.

Free pizza and refreshments will be served.


March 16th, 2017

We are pleased to announce the first session in our student seminar series 2017. Two of our students will be presenting on  WednesdayMarch 22 from 12:00 pm – 1:00 pm in ICE 8-207. 

Speaker #1: Cameron Hough – “Biological dosimetry of THz radiation for potential biomedical application


 

Background: Terahertz (THz) radiation is a form of electromagnetic energy with frequencies between the microwave and infrared bands, and is therefore non-ionizing. These frequencies couple strongly to natural oscillations of hydrogen bonds, which are found in all proteins, DNA, and cell membranes[1]. This interaction enables unique sensitivity to molecular structure that has led to the development of medical diagnostic tools that have been applied to cancer imaging with excellent contrast between diseased and normal tissue[1,2]. However, recent studies show that THz interactions are not entirely benign[1,3]; THz sources have been shown to non-thermally alter the structure/function of proteins and cell membranes, and induce localized openings in DNA. This implies the potential for: (1) Significant health risks, for which safe exposure limits are required that currently do not exist, and; (2) Novel therapies for genetic disorders (eg; cancer), for which a characterization of tissue response is required.
Objective/Hypothesis: The objective is to determine the underlying mechanisms of the observed biological effects induced by the interaction of THz radiation with hydrogen bonds in cells and tissues via analysis of differentially expressed genes/proteins. It is hypothesized that intense THz exposure will affect the structural integrity of membrane and protein structures, alter transcriptional expression levels of genes involved in important cellular processes, or induce cell death. Additionally, these effects will be dependent on THz energy, electric field, and frequency content.
Theoretical/Experimental Approach: THz exposures induce observable phenotypic effects[1,3]. These are the result of complex gene/protein signaling networks that cells utilize to respond to stimuli. By identifying and measuring concentrations of differentially expressed genes in response to THz exposures, the mechanisms underlying the phenotypic observations can be determined. Varying THz pulse parameters will alter the interaction characteristics with hydrogen bond networks and lead to phenotypic variation that can be related to measured changes in target gene/protein expression.

Biography

Cameron received his undergraduate degree in physics at the University of Alberta. His undergraduate research was in theory and technology of magnetic resonance imaging (MRI). In September 2014, he enrolled in the medical physics program at the University of Alberta, where he is currently a master’s student. He investigate the biological effects of non-ionizing radiation.

Speaker #2: Elham Baladi – “Devices and Methods Using Apertures Lined with Thin ENNZ Metamaterial Liners


 

Abstract

The miniaturization of components for microwave circuits has always been a major challenge in electromagnetics (EM), since performance is often tied to electrical length. Many devices and methods in electromagnetics use aperture arrays to transmit or radiate electromagnetic waves. The screens used in studies of extraordinary transmission and frequency selective surfaces require a relatively large number of apertures, which results in a large overall size, prompting the investigation of miniaturization methods. This work shows that transmission through miniaturized circular apertures can be vastly improved through the introduction of thin metamaterial liners exhibiting negative and near-zero (ENNZ) permittivity.

Biography

Elham Baladi received the B.S. degree in electrical engineering-communications in July 2013 from Iran University of Science and Technology (IUST), Tehran, Iran, and has been a PhD student at University of Alberta since September 2013. Her research interests include Antenna and Propagation, Metamaterials, Extraordinary Transmission, Frequency Selective Surfaces, Far-Field Sub-diffraction Imaging, and Antenna Radiation-Pattern Shaping.

Free pizza and refreshments will be served.


March 8th, 2017

We are pleased to announce the first session in our student seminar series 2017. Two of our students will be presenting on  WednesdayMarch 15 from 12:00 pm – 1:00 pm in ICE 8-207. 

Seminar #1: Haitham Abu Damis – “Wearable and On-body Antennas for Biomedical Applications


 

Abstract

Square-loop antennas for wearable applications in the 2.45 GHz (ISM) region are presented and compared. Both antennas were simulated, and then printed on flexible DuPont Kapton sheets for measurements. The standard square-loop antenna was modified by adding four circular patches to its sides in an effort to enhance performance. The new antenna is called the Quadruple Loop (QL) antenna. Simulations and measurement results show that the QL antenna demonstrated robust operation over a wider impedance bandwidth compared to that of the standard square loop antenna.

Biography

Haitham graduated from the Canadian University of Dubai (CUD) with a B.Sc. in telecommunications engineering. Throughout 2009-2013, he has worked with field programmable arrays (FPGA) and wireless sensor networks (WSN). As of 2014, he has been working on the development of body-worn antennas as part of his M.Sc. degree requirements.

Seminar #2: Rezvan Rafiee Alavi – “RWG MoM-via-Locally Corrected Nystrom Method for Source Reconstruction of Planar Very-Near-Field Measurement and Its Acceleration Using Multi-Level Fast Multipole Method


 

Abstract

Locally Corrected Nyström (LCN) method is used to solve magnetic field integral equations (MFIE) of the equivalent current method (ECM) in the planar very near-field measurement of antennas and RF circuits. The exact relationship between Rao-Wilton-Glisson (RWG) method of moments (MoM) and first-order, and zero-order LCN is established for both magnetic and electric currents to ensure normal current continuity between adjacent triangular patches. The proposed method is a point-based RWG discretization of MFIE and causes a noticeable decrease in the degree of freedom. It consequently eliminates spurious charges and significantly lowers the condition number of the impedance matrix. Moreover, it is more efficient to be accelerated by fast algorithms such as multi-level fast multipole method (MLFMM).

Biography

Rezvan Rafiee received the B.S. degree from the University of Tehran in 2009, in electrical engineering, and M.S. degree from Iran University of Science and Technology, in 2013, in Telecommunication, Fields, and Waves. Currently, she is a Ph.D. student at University of Alberta, where she has been since May 2014. Her research interests include Antenna and Propagation, Passive and Active Microwave Circuits, Numerical Methods in Electromagnetics, Inverse Electromagnetic Scattering, and Remote Sensing, and Microwave Measurements.

Free pizza and refreshments will be served.


September 7th, 2016

Photo

The IEEE Northern Canada Section Antennas & Propagation Society and the Microwave Theory & Techniques Society (IEEE NCS APS/MTTS) joint chapter is pleased to announce that we will be hosting a technical seminar by Rogers Corporation sales engineer Paul Jamiel.  Mr Jamiel will be presenting on the characterization of dielectric constants of various Rogers materials.

Where:

MEC 4-1, University of Alberta

When:

13-Sep-2016 12:00PM to 1:00PM

 Abstract

One of the key properties of PCB laminates is dielectric constant or Dk. The purpose of the presentation is to provide a basic overview of some common Dk test methods, define Process Dk and Design Dk and using Rogers Microwave Impedance Calculator to determine Design Dk.

Biography

Paul has 38 years of experience in the Printed Circuit Board industry with nearly half of those years spent manufacturing bare boards and the rest in manufacturing and selling copper clad materials.  In his current role as Sales Engineer for the NW U.S and Western Canada, Paul provides support for PCB Fabricators and guidance to PCB Designers on material selection, material stack-up considerations, and design for manufacturability.

Free pizza and refreshments will be served


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