Electromagnetics and Photonics Commons^™

Theoretical Study Of Magnetic Particles In A Shear Flow Subjected To A Uniform Magnetic Field, Christopher A. Sobecki

Doctoral Dissertations

"Magnetic manipulation of non-spherical magnetic microparticles is important for applications in shape-based and magnetic-based separations such as waste management, disease diagnostics, drug delivery, and mining. Manipulations of magnetic microparticles also include chain formation to assemble compositions for electronics, drug loading designs, and magnetorheological fluids for smart armor, hydraulic brakes, and dampers. In microfluidic devices, separation-formation-effectiveness depends on the shape of the channel, the shear rate, and the magnetic field strength and direction.

Particle separation and chain formation involved highly complex and computational expense-demanding studies in microfluidic devices, magnetic fields, and particle- particle/wall interactions. This research took complex experimental studies and …

Design And Evaluation Of The 3d Printed Electromagnetic Absorber Built With Conductive Carbon-Filled Filament, Rui Mi

Masters Theses

"This research presents an application of the resistive frequency selective surface (FSS) fabricated with a 3D printed conductive material as an electromagnetic absorber for the EMI-reducing door. This solution allows to reduce radiated emissions of a router system. The resistive frequency selective surface has a three-layer structure. The top layer is a 3D printed FSS pattern, the middle layer is an air gap, and the bottom layer is a metal plane.

The first paper presents the methodology for manufacturing a frequency selective surface using the 3D printing technology, including the material characterization, design, fabrication, and evaluation.

The unpublished content presents …

Superresolution Enhancement With Active Convolved Illumination, Anindya Ghoshroy

Dissertations, Master's Theses and Master's Reports

The first two decades of the 21st century witnessed the emergence of “metamaterials”. The prospect of unrestricted control over light-matter interactions was a major contributing factor leading to the realization of new technologies and advancement of existing ones. While the field certainly does not lack innovative applications, widespread commercial deployment may still be several decades away. Fabrication of sophisticated 3d micro and nano structures, specially for telecommunications and optical frequencies will require a significant advancement of current technologies. More importantly, the effects of absorption and scattering losses will require a robust solution since this renders any conceivable application of metamaterials …

Ultrafast Thermal Modification Of Strong Coupling In An Organic Microcavity, Bin Liu, Vinod M. Menon, Matthew Y. Sfeir

Publications and Research

There is growing interest in using strongly coupled organic microcavities to tune molecular dynamics, including the electronic and vibrational properties of molecules. However, very little attention has been paid to the utility of cavity polaritons as sensors for out-of-equilibrium phenomena, including thermal excitations. Here, we demonstrate that non-resonant infrared excitation of an organic microcavity system induces a transient response in the visible spectral range near the cavity polariton resonances. We show how these optical responses can be understood in terms of ultrafast heating of electrons in the metal cavity mirror, which modifies the effective refractive index and subsequently the strong …

Mimo Antenna For Fifth Generation Mm-Wave Applications: A Bibliometric Survey, Rajeshwari R. Malekar, Laxmikant K. Shevada, Hema D. Raut, Amruta S. Dixit, Sumit Kumar

Library Philosophy and Practice (e-journal)

Nowadays most discussed technology is mm-wave and 5G communication. The requirement of 5G technology is high bandwidth, high data rate, and low latency. To fulfil these requirements for the current growth in mobile communication multiple input multiple output antenna is used. This bibliometric paper throws light on the various methods used to improve mutual coupling between multiple antennas. Various mutual coupling reduction techniques that are used in MIMO antennas like Dielectric resonator antenna, Electromagnetic Bandgap Structure, Neutralization lines, Defected Ground Structures, Metamaterial, etc. are explained. Scopus database is used for this bibliometric review on mm-wave MIMO 5G technology from the …

A Bibliometric Survey On Ultra Wideband Multiple Input Multiple Output Antenna With Improved Isolation, Laxmikant K. Shevada, Hema D. Raut, Rajeshwari R. Malekar, Amruta S. Dixit, Sumit Kumar

Library Philosophy and Practice (e-journal)

Ultra wideband (UWB) technology remains a viable choice for very high speed data communication in future applications involving large bandwidth. For boosting the data communication efficiency and to mitigate the multipath fading issue faced by UWB system with existing narrowband systems, Multiple Input Multiple Output (MIMO) antenna system is used along with UWB. Mutual coupling which must be smaller in value plays a vital role in deciding the efficiency of MIMO antenna and hence it becomes as important aspect. The mutual coupling reduction techniques of various UWB MIMO antennas are surveyed in this bibliometric paper. The bibliometric survey aims to …

Towards Understanding Power Grid Resilience To Early-Time (E1) High-Altitude Electromagnetic Pulses, Rodrigo Elias Llanes

Electrical and Computer Engineering ETDs

Fast transient electromagnetic disturbances can occur in the atmosphere from natural occurrences such as lightning and solar flares as well as those from manmade events such as that associated with a nuclear bomb detonation. These radiated signals couple into the transmission lines and components within the electric power grid. This has prompted an increased interest in grid resilience to the Early-Time (E1) High-Altitude Electromagnetic Pulse (HEMP). Three activities were conducted which further grid resilience research. First, power substations in the United States were assessed to develop accurate layouts to be used in radiated transmission line coupling studies. Second, three pre-existing …

Conditional Generative Adversarial Network Demosaicing Strategy For Division Of Focal Plane Polarimeters, Garrett Sargent, Bradley M. Ratliff, Vijayan K. Asari

Electrical and Computer Engineering Faculty Publications

Division of focal plane (DoFP), or integrated microgrid polarimeters, typically consist of a 2 × 2 mosaic of linear polarization filters overlaid upon a focal plane array sensor and obtain temporally synchronized polarized intensity measurements across a scene, similar in concept to a Bayer color filter array camera. However, the resulting estimated polarimetric images suffer a loss in resolution and can be plagued by aliasing due to the spatially-modulated microgrid measurement strategy. Demosaicing strategies have been proposed that attempt to minimize these effects, but result in some level of residual artifacts. In this work we propose a conditional generative adversarial …

Improve The Prototype Of Low-Cost Near-Infrared Diffuse Optical Imaging System, Chen Xu, Mohammed Z. Shakil

Publications and Research

Diffuse Optical Tomography (DOT) and Optical Spectroscopy using near-infrared (NIR) diffused light has demonstrated great potential for the initial diagnosis of tumors and in the assessment of tumor vasculature response to neoadjuvant chemotherapy. The aims of this project are 1) to test the different types of LEDs in the near-infrared range, and design the driving circuit, and test the modulation of LEDs at different frequencies; 2) to test the APDs as a detector, and build the receiver system and compare efficiency with pre-built systems. In this project, we are focusing on creating a low-cost infrared transmission system for tumor and …

Antenna Radiation Element Designs For 5g Applications, Zhijun Gui

Electrical Engineering Undergraduate Honors Theses

This thesis introduced the advantage of the fifth-generation network and gave examples to the three major classes of applications categorized by International Telecommunication Union-Radiocommunication Sector. In this work, a patch antenna and a board-band bow-tie antenna with microelectromechanical switch design were modified to meet 5G communication purposes. The revised patch antenna produced a minimum S11 of -57.92dB, a resonant frequency at the 28GHz, and bandwidth of 4.55GHz. The modified design meets the requirements for wireless communication purposes. During the duplication process of the board-band bow-tie antenna design, multiple discrepancies were found, and the proposed results were not able to achieve. …

Transfer-To-Transfer Learning Approach For Computer Aided Detection Of Covid-19 In Chest Radiographs, Barath Narayanan Narayanan, Russell C. Hardie, Vignesh Krishnaraja, Christina Karam, Venkata Salini Priyamvada Davuluru

Electrical and Computer Engineering Faculty Publications

The coronavirus disease 2019 (COVID-19) global pandemic has severely impacted lives across the globe. Respiratory disorders in COVID-19 patients are caused by lung opacities similar to viral pneumonia. A Computer-Aided Detection (CAD) system for the detection of COVID-19 using chest radiographs would provide a second opinion for radiologists. For this research, we utilize publicly available datasets that have been marked by radiologists into two-classes (COVID-19 and non-COVID-19). We address the class imbalance problem associated with the training dataset by proposing a novel transfer-to-transfer learning approach, where we break a highly imbalanced training dataset into a group of balanced mini-sets and …

Polarization-Selective Modulation Of Supercavity Resonances Originating From Bound States In The Continuum, Chan Kyaw, Riad Yahiaoui, Joshua A. Burrow, Viet Tran, Kyron Keelen, Wesley Sims, Eddie C. Red, Willie S. Rockward, Mikkel A. Thomas, Andrew M. Sarangan, Imad Agha, Thomas A. Searles

Electro-Optics and Photonics Faculty Publications

Bound states in the continuum (BICs) are widely studied for their ability to confine light, produce sharp resonances for sensing applications and serve as avenues for lasing action with topological characteristics. Primarily, the formation of BICs in periodic photonic band gap structures are driven by symmetry incompatibility; structural manipulation or variation of incidence angle from incoming light. In this work, we report two modalities for driving the formation of BICs in terahertz metasurfaces. At normal incidence, we experimentally confirm polarization driven symmetry-protected BICs by the variation of the linear polarization state of light. In addition, we demonstrate through strong coupling …

Electromagnetic Interference Estimation Via Conditional Neural Processing, Edgar E. Gomez

Theses and Dissertations

The goal of this thesis is to determine the efficacy of employing Machine Learning (ML) to solve Joint Urgent Operational Need (JUON) CC-0575, which aims to develop a Common Operating Picture (COP) of the Global Positioning System (GPS) Electromagnetic Interference (EMI) environment. With the growing popularity of Artificial Neural Networks (ANNs), ML solutions are quickly gaining traction in businesses, academia and government. This in turn allows for problem solutions that were previously inconceivable using the classical programming paradigm. This thesis proposes a method to develop a COP of the battlefield via ANN ingestion of multiple-source signals and sensors. We conduct …

Sparse Bases And Bayesian Inference Of Electromagnetic Scattering, John Lee

Theses and Dissertations

Many approaches in CEM rely on the decomposition of complex radiation and scattering behavior with a set of basis vectors. Accurate estimation of the quantities of interest can be synthesized through a weighted sum of these vectors. In addition to basis decompositions, sparse signal processing techniques developed in the CS community can be leveraged when only a small subset of the basis vectors are required to sufficiently represent the quantity of interest. We investigate several concepts in which novel bases are applied to common electromagnetic problems and leverage the sparsity property to improve performance and/or reduce computational burden. The first …

Development And Characterization Of Metal Contacts For Graded Composition Ingan Solar Cells, Reem E. Alhelais

Graduate Theses and Dissertations

There is an increasing demand for high-power electronic components and optoelectronic devices with low-loss and high efficiency. III-nitride semiconductor materials have demonstrated great potential for high-power, high-frequency, and high-temperature applications because of their remarkable and wide-ranging electronic and physical properties. These material systems, including alloys of AlN, GaN, and InN, are currently being explored for their potential to develop efficient photovoltaic cells. They can potentially achieve higher efficiency because of their very high direct wide band edge, absorption coefficients, and resistance to defects. The compositionally graded Group III-nitride alloy allows access to a large range of energies by varying the …

Review Of The Emc Aspects Of Internet Of Things, Jiyu Wu, Yihong Qi, Guang Gong, Jun Fan, Miao Miao, Wei Yu, Jianhua Ma, James L. Drewniak

Electrical and Computer Engineering Faculty Research & Creative Works

Wireless devices are the largest part of the Internet-of-Things (IoT) units. Radiated, such as specific absorption rate and spurious related issues are regulated by the standards bodies. The functionality performance will greatly influence IoT system stability, user experience, and cost. Radio receiver desensitization and coexistence aspects of IoT devices are discussed in this article. Measurement technologies are briefly reviewed for transmit/receive mode only of single-input single-output (SISO), and multiple-input multiple-output (MIMO) devices, to provide a means of device performance evaluation and electromagnetic interference troubleshooting. An understanding of the electromagnetic compatibility aspects of the IoT and its measurement methods can help …

Simulation Of An Sp8t 18 Ghz Rf Switch Using Smt Pin Diodes, Andre De Souza Vigano

Master's Theses

Radio frequency (RF) and microwave switches are widely used in several different applications including radar, measurement systems, telecommunications, and other areas. An RF switch can control a radar’s transmit vs. receive mode, select the operating band, or direct an RF signal to different paths. In this study, a single pole eight throw (SP8T) switch using only Surface Mount (SMT) components is designed and simulated in Keysight’s Advanced Design System (ADS). Single pole eight throw is defined as one input and eight possible outputs. A star network configuration with series-shunt PIN diode switches is used to create the 8-way RF switch. …

Detailed Modeling Of The Flash Hydrolysis Of Algae For Biofuel-Production In Comsol Multiphysics, Noah Joseph Legrand

Mechanical & Aerospace Engineering Theses & Dissertations

Algae-derived biofuels are being commercialized as an important renewable energy source. Like any new technology, conversion improvements are desired, including reductions in process complexity and better utilization of the entire microalgae feedstock. The Old Dominion Biomass Laboratory has focused on flash hydrolysis for algae biofuel production. That process involves rapidly heating algae and water mixed as a slurry to a subcritical state. Results from small-scale bench tests are promising, but process scale up is a challenge. Currently there exists a pilot laboratory scale system utilizing induction heating in order to reach controlled reaction temperatures with a reaction duration of 10 …

An Analysis Of The Benefits And Difficulties Of Aerial Magnetic Vector Navigation, Aaron J. Canciani, Christopher J. Brennan

Faculty Publications

Recent successful flight tests have demonstrated scalar magnetic anomaly navigation to be a viable GPS-alternative navigation system. These flight tests matched magnetic field measurements to maps of the Earth's crustal magnetic field in order to navigate. Scalar magnetic navigation uses only the magnetic field intensity, not direction, in order to navigate. While it appears obvious to extend aerial magnetic navigation to use the full vector field, in practice there are substantial obstacles to doing so. This article explores the key challenges of magnetic vector navigation including current sensor limitations, lack of high frequency magnetic vector maps of the Earth's crust, …

Fourier Transform Infrared Spectroscopy For The Measurement Of Gesn/(Si)Gesn, Solomon Opeyemi Ojo

Graduate Theses and Dissertations

Photoluminescence (PL) and Electroluminescence (EL) characterization techniques are important tools for studying the optical and electrical properties of (Si)GeSn. Light emission from these PL and EL measurements provides relevant information on material quality, bandgap energy, current density, and device efficiency. Prior to this work, the in-house PL set-up of this lab which involves the use of a commercially-obtained dispersive spectrometer was used for characterizing both GeSn thin film and fabricated devices, but these measurements were limited by issues bordering on low spectral resolution, spectral artifacts, and poor signal-to-noise ratio (SNR) thereby resulting in the possible loss of vital information and …