Electromagnetics and Photonics Commons^™

High-Frequency Accurate Dual-Side Equivalent Circuit Model For Transformers, Reza Vahdani, Junyong Park, Manish Kizhakkeveettil Mathew, Zhekun Peng, Chiuk Song, Hyucksu Kweon, Jiang Lijun, Donghyun Kim

Electrical and Computer Engineering Faculty Research & Creative Works

This study delves into the modeling of a transformer in the frequency range of 100 KHz to 30 MHZ. The coupling coefficient was considered as a function of leakage and self-inductance and incorporated in the optimization process of transformer modeling in the proposed method. The equivalent circuit focused on the critical aspects of leakage inductance, parasitic capacitance, and winding effects. At first, the winding effect of an air-core inductor over wide frequency range with both single-layer and double-layer windings was shown. Then an equivalent circuit was proposed to model a transformer over this frequency range. The comparison between the measured …

The Electromagnetic Bayonet: Development Of A Scientific Computing Method For Aperture Antenna Optimization, Michael P. Ingold

Theses and Dissertations

The quiet zone of a radar range is the region over which a transmitted EM field approximates a uniform plane wave to within some finite error tolerance. Any target to be measured must physically fit within this quiet zone to prevent excess measurement error. Compact radar ranges offer significant operational advantages for performing RCS measurements but their quiet zone sizes are constrained by space limitations. In this work, a scientific computing approach is used to investigate whether equivalent-current transmitters can be designed that generate larger quiet zones than a conventional version at short range. A time-domain near-field solver, JefimenkoModels, was …

A Study On Electromagnetic Topology Optimization Using Binary Particle Swarm Algorithm, Mohammad Sazzad Hossain

Electrical and Computer Engineering ETDs

Topology optimization is a state-of-the-art tool for detecting the best material layout in a physical space to obtain certain goals. Initially developed as a structural engineering tool, it has been recently used in electromagnetics and has shown immense potential. The aim of this work is to build a framework for applying the topology optimization method in electromagnetics using a modified binary particle swarm optimization (BPSO) algorithm. In this thesis, a very classic problem of coax to waveguide transition has been considered, and a novel solution has been given using topology optimization. The steps to implementing topology optimization using BPSO have …

Parametric Optimization Of Visible Wavelength Gold Lattice Geometries For Improved Plasmon-Enhanced Fluorescence Spectroscopy, Casey A. Norville

Graduate Theses, Dissertations, and Problem Reports (ETD)

The exploitation of spectro-plasmonics will allow for innovations in optical instrumentation development and the realization of more efficient optical biodetection components. Biosensors have been shown to improve the overall quality of life through real-time detection of various antibody-antigen reactions, biomarkers, infectious diseases, pathogens, toxins, viruses, etc. has led to increased interest in the research and development of these devices. Further advancements in modern biosensor development will be realized through novel electrochemical, electromechanical, bioelectrical, and/or optical transduction methods aimed at reducing the size, cost, and limit of detection (LOD) of these sensor systems. One such method of optical transduction involves the …

Optimum Design Of Axial Flux Pm Machines Based On Electromagnetic 3d Fea, Narges Taran

Theses and Dissertations--Electrical and Computer Engineering

Axial flux permanent magnet (AFPM) machines have recently attracted significant attention due to several reasons, such as their specific form factor, potentially higher torque density and lower losses, feasibility of increasing the number of poles, and facilitating innovative machine structures for emerging applications. One such machine design, which has promising, high efficiency particularly at higher speeds, is of the coreless AFPM type and has been studied in the dissertation together with more conventional AFPM topologies that employ a ferromagnetic core.

A challenge in designing coreless AFPM machines is estimating the eddy current losses. This work proposes a new hybrid analytical …

Two-Level Surrogate-Assisted Differential Evolution Multi-Objective Optimization Of Electric Machines Using 3-D Fea, Narges Taran, Dan M. Ionel, David G. Dorrell

Power and Energy Institute of Kentucky Faculty Publications

A two-level surrogate-assisted optimization algorithm is proposed for electric machine design using 3-D finite-element analysis (FEA). The algorithm achieves the optima with much fewer FEA evaluations than conventional methods. It is composed of interior and exterior levels. The exploration is performed mainly in the interior level, which evaluates hundreds of designs employing affordable kriging models. Then, the most promising designs are evaluated in the exterior loop with expensive 3-D FEA models. The sample pool is constructed in a self-adjustable and dynamic way. A hybrid stopping criterion is used to avoid unnecessary expensive function evaluations.

Assisted Switched Reluctance Machines, Amy Robinson

Honors Scholar Theses

Switched reluctance machine (SRM) modifications in both control schemes and physical design have been steadily increasing in academia to improve machine performance. Assisted switched reluctance machines (ASRMs) are a type of design modification for SRMs. Permanent magnets (PMs) and electromagnetic DC coils (DCC) are being added to the SRM to improve its torque output and overall efficiency. The choice for the design modification has been evolving throughout the decades. The focus has shifted from adding DCC to ASRM to adding PMs to ASRMs. This paper reviews the research trends of ASRMs and includes an analysis of the modified stator yoke …

Design Of An Asymmetric Reluctance Machine For A Generator Application, Bryan David Marquet

Open Access Theses

This work compares an Asymmetric Reluctance Machine (ARM) to a Uniform air Gap Reluctance Machine (UGRM) for a generator application. The ARM employs an asymmetric rotor pole to increase machine performance, specifically increasing torque density. A multi-objective optimization is employed to minimize mass and loss subject to design constraints. Two machines are compared in terms of their Pareto-optimal fronts.

Design Method For Wideband Circularly Polarized Slot Antennas, Adam Narbudowicz, Matthias John, Vit Sipal, Xiulong Bao, Max Ammann

Articles

A compact ultrawideband (UWB) circularly polarized (CP) slot antenna is proposed with a methodology for automated reoptimization for packaging with proprietary devices. The slot structure employs a dual-feed with an integrated compact UWB phase shifter. The design process involves an advanced optimization algorithm and demonstrates the use of spline curves for generation of CP signals. These allow easy optimization, while preserving phase coherency across a wideband. The prototyped antennahas a CP bandwidth of 54% (from 3.2 to 6.1 GHz).

Time Domain Simulation Of Novel Photovoltaic Materials, Haejun Chung

Open Access Theses

Thin-film silicon-based solar cells have operated far from the Shockley- Queisser limit in all experiments to date. Novel light-trapping structures, however, may help address this limitation. Finite-difference time domain simulation methods offer the potential to accurately determine the light-trapping potential of arbitrary dielectric structures, but suffer from materials modeling problems. In this thesis, existing dispersion models for novel photovoltaic materials will be reviewed, and a novel dispersion model, known as the quadratic complex rational function (QCRF), will be proposed. It has the advantage of accurately fitting experimental semiconductor dielectric values over a wide bandwidth in a numerically stable fashion. Applying …

Advanced Design Methodologies And Novel Applications Of Reflectarray Antennas, Payam Nayeri

Electronic Theses and Dissertations

Reflectarray antennas combine the numerous advantages of printed antenna arrays and reflector antennas and create a hybrid high-gain antenna with a low-profile, low-mass, and diversified radiation performance. Reflectarrays are now emerging as the new generation of high-gain antennas for long-distance communications. In this dissertation, some advanced concepts demonstrating novel features of reflectarray antennas are presented. • First, various approaches for radiation analysis of reflectarray antennas are described and implemented. Numerical results are then presented for a variety of systems and the advantages, limitations, and accuracy of these approaches are discussed and compared with each other. • A broadband technique by …