Lakehead University Knowledge Commons

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Theory and design of smart RF components using the novel FPMS technology
(2026) Ali, Shahinshah; Ghaffar, Farhan Abdul; Zhou, Yushi; Christoffersen, Carlos; Roy, Langis; Wang, Ying
The increasing demand for intelligent wireless communication systems has accelerated the development of reconfigurable microwave components capable of adapting their electromagnetic characteristics in real time. Modern applications, including phased-array antennas, satellite communications, radar systems, fifth-generation (5G) and emerging sixth-generation (6G) wireless networks, require compact, low-loss, and electronically reconfigurable microwave devices that can dynamically control the radiation characteristics of antennas. Conventional approaches generally rely on phased arrays with complex feeding networks or transmission-line-based phase shifters, which often suffer from increased circuit complexity, larger physical size, higher insertion loss, and significant power consumption. Consequently, there is a growing need for alternative reconfigurable technologies that simplify system architecture while maintaining high performance. This thesis investigates the concept of the Field Programmable Microwave Substrate (FPMS) as a new platform for realizing reconfigurable microwave components through dynamic control of the effective permittivity of the propagation medium. The research demonstrates two major applications of the FPMS concept. The first contribution presents a programmable artificial magnetic conductor (AMC) integrated with a single antenna element to achieve electronic beam steering without employing a conventional phased-array architecture. The proposed FPMS-AMC simultaneously functions as a reflective surface that suppresses backside radiation while dynamically controlling the reflection phase to steer the main beam. A beam steering range of approximately ±30° is achieved while maintaining a maximum realized gain of 7.2 dBi at 10 GHz. The fabricated prototype validates the proposed concept and demonstrates good agreement between simulated and measured results. The second contribution introduces a continuously tunable phase shifter based on a programmable dielectric waveguide realized using FPMS technology. Unlike conventional phase shifters that employ switched transmission lines, loaded-line networks, or reflection-type circuits, the proposed design controls the propagation constant by electrically tuning the effective permittivity of the dielectric guiding region. An analytical model based on guided-wave theory is developed for both homogeneous and non-homogeneous dielectric configurations. The analytical predictions are verified through full-wave simulations and experimental measurements. The fabricated prototype demonstrates a continuous phase tuning range of approximately 300° at 2.5 GHz with good agreement between theoretical, simulated, and measured results. Overall, this thesis establishes the FPMS as a versatile reconfigurable electromagnetic (EM) platform capable of controlling both radiation characteristics and guided-wave propagation through programmable dielectric properties. The proposed analytical framework, validated experimental results, and demonstrated antenna applications provide a foundation for future reconfigurable microwave and antenna systems requiring compact size, continuous tunability, and simplified beam steering architectures.
Reproducing the French-Canadian Settler Collective in Ontario through French Language rights
(Osgoode Digital Commons, 2026) Woolnough, Monique
Much of settler colonial theory and studies in Canada has focused on the dominant British settler colonial power, with an emerging spotlight on Quebec. Little attention has been paid to French-Canadian settler colonialism in French-Canadian minority provinces such as Ontario. This research aims to make visible this gap in attention and begin to fill in its contours by understanding how the French-Canadian settler colonial project operates in Ontario through law. Through the application of Indigenous, settler colonial, socio-legal and critical feminist and race theories to a review of narrative themes in the jurisprudence of courts and tribunals interpreting Ontario’s French Language Services Act, including the purposes of the Act, the vulnerability of Francophones and the role of Francophone institutions, the author endeavors to explore the unique ways in which settler colonial consciousness is deployed, reproduced and reinforced in law.
A single-phase H-type five-level Current Source Inverter
(2026) Zhou, Zhiming; Wei, Qiang
Current Source Inverters (CSIs) have drawn growing attention in modern energy conversion systems due to their inherent voltage-boosting capability, reliable short-circuit protection, and smooth output current profiles. This dissertation investigates single-phase multilevel CSIs and systematically reviews the evolution of three-level, five-level, and seven-level topologies. The advantages and limitations of different five-level CSI configurations are further analyzed, and the trade-off between output current quality, circuit complexity, and efficiency indicates that the five-level CSI provides a suitable balance for practical applications. However, conventional five-level CSIs suffer from dc current imbalance, which necessitates complicated active balancing control schemes. Although a recently developed single-phase X-type five-level CSI successfully achieves inherent current balancing without complex external controllers, it requires significantly large DC inductors, which inevitably leads to increased system volume, higher manufacturing costs, and degraded efficiency. To overcome these limitations, this dissertation presents a novel single-phase H-type five-level CSI. The proposed topology retains the self-balancing capability for inductor currents while significantly reducing the required DC inductance across its full operating range. The operating principle, modulation scheme, passive component design, inductor current self-balancing, switch voltage stresses, and power losses of the proposed inverter are investigated. A comparative analysis is performed between the proposed H-type and X-type five-level CSIs in terms of required dc inductance, peak voltage of switches, semiconductor device count, and efficiency. Finally, the performance of the proposed inverter is verified through MATLAB/Simulink simulations and lab-scale experiments.
Forest harvesting generates attractive breeding habitat for male Eastern Gray Treefrogs (Dryophytes versicolor) at their poleward range edge
(2026) Sim, Abby; Algar, Adam; Dey, Cody; Lee-Yaw, Julie
Climate change and anthropogenic disturbance are changing many species' ranges. Anthropogenic habitat modification typically restricts species ranges, but at poleward range edges it could create warmer microclimates that offset marginal climatic conditions. I hypothesized that clearcutting is creating warmer, more favourable breeding habitat at the expanding, poleward range edge of the Eastern Gray Treefrog (Dryophytes versicolor). Using an autodetection tool and passive acoustic monitoring, I found higher calling activity at recently clearcut ponds compared to forested ponds. Structural equation modelling revealed significant direct effects of warmer air and pond surface temperatures on calling activity. Reduced canopy cover, leading to higher pond surface temperatures, were the key mediators between harvesting and increased calling activity. Clearcut ponds were 1.9±0.5 degrees warmer than forested ponds during the breeding season, which could facilitate faster tadpole development. However, I found no difference in tadpole food resources (periphyton production) between clearcut and forested ponds. These findings demonstrate how microclimate and anthropogenic disturbance influence breeding habitat at a poleward range edge. However, we still require crucial information on pond preference of females, tadpole development, and juvenile survival as a measure of fitness, and to determine whether anthropogenic habitat modification is facilitating this range expansion.
Efficient deep learning frameworks for LiDAR point cloud analysis: from classification to 3D object detection
(2026) Rahman, Fahim Ur; Akilan, Thangarajah; Yassine, Abdulsalam; Deng, Yong; Alkhateeb, Abedalrhman; Zhou, Yushi
Reliable three-dimensional (3D) perception from Light Detection and Ranging (LiDAR) point clouds is essential for autonomous driving, where vehicles must recognize and localize traffic participants from sparse, irregular, and range-dependent point returns to plan and act safely. Existing methods struggle to meet this need efficiently: many high-accuracy classifiers and detectors rely on heavy transformers or deep attention stacks that are poorly matched to real-time or resource-constrained deployment, pillar-based Bird’s-Eye-View (BEV) detectors apply a uniform receptive field regardless of local point density—so sparse, far-range objects receive no more context than dense, near-range ones—and single-resolution BEV grids force a trade-off in which fine cells preserve localization precision but lack scene context, while coarse cells capture context but destroy sub-meter precision in the process. This thesis addresses these limitations through a phased research built around a single key idea: adaptive gating and multi-resolution fusion, rather than uniformly heavier computation to let LiDAR perception be both accurate and efficient. In the first phase, SiGF-Net performs point cloud object classification using a dual-stream architecture in which semantic-derived sigmoid gating adaptively fuses multi-scale geometric features with semantic context (Chapter 3). In the second phase, AG-DPE extends this principle to scene-level LiDAR 3D object detection, using a lightweight density estimator to guide continuous gating across fine, mid, and coarse BEV scales and to condition attention on local point sparsity within a pillar-based pipeline (Chapter 4). In the third phase, DPCA-Net resolves the single-grid detail–context trade-off by encoding each LiDAR sweep into complementary fine and coarse BEV grids and fusing them through bidirectional cross-stream attention at mid-level, followed by semantic-gated injection (Chapter 5). Experiments on standard benchmarks validate each phase. SiGF-Net reaches 94.17% accuracy on ModelNet40 and 81.49% on ScanObjectNN with only 0.15M parameters and 0.52 GFLOPs, giving an efficiency score of 9.56 that exceeds competing methods. AG-DPE improves KITTI validation mAP over a PointPillars baseline from 63.05% to 66.53% on 3D and from 64.08% to 68.81% on BEV with only 24.5K additional parameters (+0.5%), and remains competitive on nuScenes with 0.696 mAP / 0.737 NDS and Waymo with 0.8320 AP/L2 / 0.8170 APH/L2. DPCANet achieves the highest overall Moderate mAP among compared methods on the KITTI validation set holding 75.58% 3D, 73.26% BEV, +11.33 over PointPillars, with the largest gains on Pedestrian and Cyclist, and remains competitive on the Waymo while scoring 88.05 AP L1 / 82.52 APH L2 and nuScenes by 70.0% mAP / 73.9 NDS test leaderboards. Collectively, these results demonstrate that explicit density- and context-aware gating provides an effective, generalizable alternative to uniformly heavy architectures for LiDAR perception, delivering competitive or state-of-the-art accuracy from object-level classification through scene-level 3D detection while remaining efficient enough.