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Side Lobe Level Reduction And Array Thinning Of Concentric Circular Antenna Arrays, Alzahraa H. Nosier, Ahmed M. Elkhawaga, Mohamed E. Nasr, Nessim M. Mahmoud, Amr H. Hussein 2024 Electronics and Electrical Communications Engineering Dept., Faculty of Engineering, Tanta University, Tanta, Egypt.

Side Lobe Level Reduction And Array Thinning Of Concentric Circular Antenna Arrays, Alzahraa H. Nosier, Ahmed M. Elkhawaga, Mohamed E. Nasr, Nessim M. Mahmoud, Amr H. Hussein

Mansoura Engineering Journal

This paper presents a new beamforming technique based on the hybrid combination of the convolution algorithm (CA) and the genetic algorithm (GA) for reducing side lobe level (SLL) and array thinning of concentric circular antenna arrays (CCAA), which is denoted as C/GA technique. The CA determines the excitations of the elements, while the GA optimizes the radii of the circular arrays to adjust the half-power beamwidth (HPBW). For CCAA consisting of uniform feeding circular arrays, we assume that there are excitation coefficients that are distributed symmetrically around the array center and arranged in a vector. The excitation vector is convolved …


Reinventing Integrated Photonic Devices And Circuits For High Performance Communication And Computing Applications, Venkata Sai Praneeth Karempudi 2024 University of Kentucky

Reinventing Integrated Photonic Devices And Circuits For High Performance Communication And Computing Applications, Venkata Sai Praneeth Karempudi

Theses and Dissertations--Electrical and Computer Engineering

The long-standing technological pillars for computing systems evolution, namely Moore's law and Von Neumann architecture, are breaking down under the pressure of meeting the capacity and energy efficiency demands of computing and communication architectures that are designed to process modern data-centric applications related to Artificial Intelligence (AI), Big Data, and Internet-of-Things (IoT). In response, both industry and academia have turned to 'more-than-Moore' technologies for realizing hardware architectures for communication and computing. Fortunately, Silicon Photonics (SiPh) has emerged as one highly promising ‘more-than-Moore’ technology. Recent progress has enabled SiPh-based interconnects to outperform traditional electrical interconnects, offering advantages like high bandwidth density, …


Photoluminescence Switching In Quantum Dots Connected With Fluorinated And Hydrogenated Photochromic Molecules, Ephraiem S. Sarabamoun, Jonathan M. Bietsch, Pramod Aryal, Amelia G. Reid, Maurice Curran, Grayson Johnson, Esther H. R. Tsai, Charles W. Machan, Guijun Wang, Joshua J. Choi 2024 University of Virginia

Photoluminescence Switching In Quantum Dots Connected With Fluorinated And Hydrogenated Photochromic Molecules, Ephraiem S. Sarabamoun, Jonathan M. Bietsch, Pramod Aryal, Amelia G. Reid, Maurice Curran, Grayson Johnson, Esther H. R. Tsai, Charles W. Machan, Guijun Wang, Joshua J. Choi

Chemistry & Biochemistry Faculty Publications

We investigate switching of photoluminescence (PL) from PbS quantum dots (QDs) crosslinked with two different types of photochromic diarylethene molecules, 4,4'-(1-cyclopentene-1,2-diyl)bis[5-methyl-2-thiophenecarboxylic acid] (1H) and 4,4'-(1-perfluorocyclopentene-1,2-diyl)bis[5-methyl-2-thiophenecarboxylic acid] (2F). Our results show that the QDs crosslinked with the hydrogenated molecule (1H) exhibit a greater amount of switching in photoluminescence intensity compared to QDs crosslinked with the fluorinated molecule (2F). With a combination of differential pulse voltammetry and density functional theory, we attribute the different amount of PL switching to the different energy levels between 1H and 2F molecules which result in different potential barrier …


Series Aperture Coupled Fed Phased Array Antenna, Guang Yang 2023 Southern Methodist University

Series Aperture Coupled Fed Phased Array Antenna, Guang Yang

Electrical Engineering Theses and Dissertations

Phased arrays are employed in a wide range of civil and Military contexts, including RADAR, cellular communications, and satellite communications. However, modern phased-array antennas require complex design and bulky structure at high costs, hindering their implementation in many applications. The critical aspect of a phased array design lies in power splitting with a proper phase to each radiating element. Conventional power splitters such as quarter-wavelength or Wilkinson power splitters suffer problems associated with complex array network and high power dissipation. Furthermore, popular phase shifters such as MEMS switch, ferrite-based or PIN diode have drawbacks of low power-handling capability, expensive packaging, …


Compact Vhf And Uhf Antennas For Integration With Saw Devices In Harsh Environment, Sri Lekha Srimat Kilambi 2023 University of Maine

Compact Vhf And Uhf Antennas For Integration With Saw Devices In Harsh Environment, Sri Lekha Srimat Kilambi

Electronic Theses and Dissertations

With increasing demand for harsh environment (HE) wireless sensor applications, the need for antennas capable of operating under temperatures up to 1000° C and under corrosive and erosive environments also increases. These environments place severe survivability, stability, and performance demands on antennas designed and fabricated to operate in such conditions.

This work focuses on the design, fabrication, simulation and performance investigation of a compact (~1/25th to 1/10th of a wavelength) combined helical and microstrip antenna design operating as a normal mode helical antenna structure (NMHAS) around 300MHz. The ground plane of the microstrip line also serves as a ground plane …


Fourier Analysis And Optimization Of Inductive Wireless Power Transfer For Electric Vehicle Charging, Andrew P. Foote 2023 University of Tennessee, Knoxville

Fourier Analysis And Optimization Of Inductive Wireless Power Transfer For Electric Vehicle Charging, Andrew P. Foote

Doctoral Dissertations

With the growth of electric vehicle (EV) popularity, different charging options to increase user convenience and reduce charging time such as high power wireless charging are increasingly being developed and researched. Inductive wireless power transfer (WPT) systems for EVs must meet specifications such as stray field, battery power and voltage operating range, efficiency, and ground clearance. The coil geometry and design have a large impact in meeting these constraints. Typical design approaches include iterative analysis of predetermined coil geometries to identify candidates that meet these constraints.

This work instead directly generates WPT coil shapes and magnetic fields to meet specifications …


Additive Manufacturing Of Magnetic Materials For Electric Motor And Generator Applications, Haobo Wang 2023 University of Tennessee, Knoxville

Additive Manufacturing Of Magnetic Materials For Electric Motor And Generator Applications, Haobo Wang

Doctoral Dissertations

This work details the research into the 3D Printing, also known as Additive Manufacturing (AM), of both impermanent and permanent magnets. This work also details the research in enabling such AM magnets in electrical machine applications, primarily motors and generators. The AM processes of many types of magnets are described in detail. The material properties of such AM magnets are also described. The two main types of AM magnets that are discussed in detail are AM NdFeB, and AM Silicon Steel. The implementation of AM NdFeB as rotor magnets, and the implementation of AM Silicon Steel as rotor and stator …


Gpu Based Monte Carlo Estimation Of Eddy Current Losses In Electromagnetic Coil-Core System, Adwaith Ravichandran 2023 Florida Institute of Technology

Gpu Based Monte Carlo Estimation Of Eddy Current Losses In Electromagnetic Coil-Core System, Adwaith Ravichandran

Theses and Dissertations

A novel parallelizable probabilistic approach to model eddy currents in AC electromagnets is presented in this research. Consequently, power loss associated with the formation of these eddy currents is estimated and validated using experimental data. Furthermore, predicting the effect of ferromagnetic alternating field enhancement on power loss in the source excitation winding has been an active area of research. Unlike a stationary field, an alternating sinusoidal field diffuses partially into the ferromagnetic material leading to a predictably sub-optimal field enhancement. To model these physics, finite element techniques employ nonlinear iterative solvers which are time consuming. A novel method is developed …


Directional Microwave Emission From Femtosecond-Laser Illuminated Linear Arrays Of Superconducting Rings, Thomas J. Bullard, Kyle Frische, Charlie Ebbing, Stephen J. Hageman, John Morrison, John Bulmer, Enam A. Chowdury, Michael L. Dexter, Timothy J. Haugan, Anil K. Patniak 2023 Air Force Research Laboratory

Directional Microwave Emission From Femtosecond-Laser Illuminated Linear Arrays Of Superconducting Rings, Thomas J. Bullard, Kyle Frische, Charlie Ebbing, Stephen J. Hageman, John Morrison, John Bulmer, Enam A. Chowdury, Michael L. Dexter, Timothy J. Haugan, Anil K. Patniak

Faculty Publications

We examine the electromagnetic emission from two photo-illuminated linear arrays composed of inductively charged superconducting ring elements. The arrays are illuminated by an ultrafast infrared laser that triggers microwave broadband emission detected in the 1–26 GHz range. Based on constructive interference from the arrays a narrowing of the forward radiation lobe is observed with increasing element count and frequency demonstrating directed GHz emission. Results suggest that higher frequencies and a larger number of elements are achievable leading to a unique pulsed array emitter concept that can span frequencies from the microwave to the terahertz (THz) regime.


Controlled Radiation Capsule For Precision And Rapid Cancer Treatment, Hoseon Lee, Zsolt Kollar, Bailey R. White, Junia Nguyen, David Roque, Sowjanya Palagani 2023 Kennesaw State University

Controlled Radiation Capsule For Precision And Rapid Cancer Treatment, Hoseon Lee, Zsolt Kollar, Bailey R. White, Junia Nguyen, David Roque, Sowjanya Palagani

Symposium of Student Scholars

This research aims to transform cancer treatment through the optimization of brachytherapy, with a focus on reducing treatment duration, setup complexities, and financial burdens, all while emphasizing patient safety. Patients living at a distance from radiation clinics, particularly those undergoing extended Low Dose Radiation brachytherapy, often struggle with the formidable financial challenges associated with securing nearby accommodations. In response to these issues, the research introduces a radiation capsule designed to condense the conventional six-month treatment period to approximately just one week, thereby significantly reducing the duration of required accommodations. This capsule is especially relevant considering the construction cost of $40 …


Uncertainties In Retrieval Of Remote Sensing Reflectance From Ocean Color Satellite Observations, Eder I. Herrera Estrella 2023 The Graduate Center, City University of New York

Uncertainties In Retrieval Of Remote Sensing Reflectance From Ocean Color Satellite Observations, Eder I. Herrera Estrella

Dissertations, Theses, and Capstone Projects

Ocean Color radiometry uses remote sensing to interpret ocean dynamics by retrieving remote sensing reflectance (𝑅𝑟𝑠) from satellite imagery at different scales and over different time periods. 𝑅𝑟𝑠 spectrum characterizes the ocean color that we observe, and from which we can discern concentrations of chlorophyll, organic and inorganic particles, and carbon fluxes in the ocean and atmosphere. 𝑅𝑟𝑠 is derived from the total radiance at the top of the atmosphere (TOA). However, it only represents up to ten percent of the total signal. Hence, the retrieval of 𝑅𝑟𝑠 from the total radiance at TOA involves the application of atmospheric correction …


Mathematical Model Of An Industrial Robot Built On The Basis Of Linear Motion Mechatron Modules, Matyokubov Nurbek Rustamovich, Rakhimov Temurbek Omonboyevich 2023 Tashkent state technical university named after Islom Karimov, Address: 2, University str., 100095, Tashkent, Uzbekistan. E-mail: nm85@mail.ru,

Mathematical Model Of An Industrial Robot Built On The Basis Of Linear Motion Mechatron Modules, Matyokubov Nurbek Rustamovich, Rakhimov Temurbek Omonboyevich

Chemical Technology, Control and Management

The use of Industry 4.0 technologies in modern production serves to increase production efficiency. Robots and robotic complexes with innovative intelligent control are widely used in industrial production. However, studying their mechanical part, linear motion mechatronic modules and control system is a complex object. The variety and complexity of control methods and operating modes negatively affects the operator's working time and production productivity. In such cases, it is necessary to improve control methods and develop technologies used in industry, including robots and robotic manipulators, which allow to perform short movements with high accuracy and speed. In the article, the mathematical …


Boundary Integral Equation Methods For Superhydrophobic Flow And Integrated Photonics, Kosuke Sugita 2023 New Jersey Institute of Technology

Boundary Integral Equation Methods For Superhydrophobic Flow And Integrated Photonics, Kosuke Sugita

Dissertations

This dissertation presents fast integral equation methods (FIEMs) for solving two important problems encountered in practical engineering applications.

The first problem involves the mixed boundary value problem in two-dimensional Stokes flow, which appears commonly in computational fluid mechanics. This problem is particularly relevant to the design of microfluidic devices, especially those involving superhydrophobic (SH) flows over surfaces made of composite solid materials with alternating solid portions, grooves, or air pockets, leading to enhanced slip.

The second problem addresses waveguide devices in two dimensions, governed by the Helmholtz equation with Dirichlet conditions imposed on the boundary. This problem serves as a …


The Relaying Network In Free-Space Optical Communications Using Optical Amplifiers In Cascaded Configuration, Ucuk Darusalam, Arockia Bazil Raj, Fitri Yuli Zulkifli, Purnomo Sidi Priambodo, Eko Tjipto Rahardjo 2023 Department of Informatics, Universitas Siber Asia, Ragunan, Pasar Minggu 12550, Indonesia

The Relaying Network In Free-Space Optical Communications Using Optical Amplifiers In Cascaded Configuration, Ucuk Darusalam, Arockia Bazil Raj, Fitri Yuli Zulkifli, Purnomo Sidi Priambodo, Eko Tjipto Rahardjo

Makara Journal of Technology

Optical relaying is the best technique to implement free-space optical (FSO) communications as a terrestrial platform. However, atmospheric turbulence (AT) limits the optical-propagation path length. In this study, the implementation of some optical amplifiers (OAs) in cascaded configuration, namely, erbium-doped fiber amplifiers, semiconductor OAs, and Raman amplifiers (RAs), are investigated through simulation. This study aims to search for the maximum link distance of an optical propagation and enhance the FSO performance caused by each configuration of OAs. The optical relaying network consists of three nodes, with each node designed with a space of several kilometers under the influence of AT. …


Design And Fabrication Of A Trapped Ion Quantum Computing Testbed, Christopher A. Caron 2023 University of Massachusetts Amherst

Design And Fabrication Of A Trapped Ion Quantum Computing Testbed, Christopher A. Caron

Masters Theses

Here we present the design, assembly and successful ion trapping of a room-temperature ion trap system with a custom designed and fabricated surface electrode ion trap, which allows for rapid prototyping of novel trap designs such that new chips can be installed and reach UHV in under 2 days. The system has demonstrated success at trapping and maintaining both single ions and cold crystals of ions. We achieve this by fabricating our own custom surface Paul traps in the UMass Amherst cleanroom facilities, which are then argon ion milled, diced, mounted and wire bonded to an interposer which is placed …


Exploring Bistatic Scattering Modeling For Land Surface Applications Using Radio Spectrum Recycling In The Signal Of Opportunity Coherent Bistatic Simulator, Dylan R. Boyd 2023 Mississippi State University

Exploring Bistatic Scattering Modeling For Land Surface Applications Using Radio Spectrum Recycling In The Signal Of Opportunity Coherent Bistatic Simulator, Dylan R. Boyd

Theses and Dissertations

The potential for high spatio-temporal resolution microwave measurements has urged the adoption of the signals of opportunity (SoOp) passive radar technique for use in remote sensing. Recent trends in particular target highly complex remote sensing problems such as root-zone soil moisture and snow water equivalent. This dissertation explores the continued open-sourcing of the SoOp coherent bistatic scattering model (SCoBi) and its use in soil moisture sensing applications. Starting from ground-based applications, the feasibility of root-zone soil moisture remote sensing is assessed using available SoOp resources below L-band. A modularized, spaceborne model is then developed to simulate land-surface scattering and delay-Doppler …


Characteristics Of Refractivity And Sea State In The Marine Atmospheric Surface Layer And Their Influence On X-Band Propagation, Douglas Matthew Pastore 2023 Coastal Carolina University

Characteristics Of Refractivity And Sea State In The Marine Atmospheric Surface Layer And Their Influence On X-Band Propagation, Douglas Matthew Pastore

Electronic Theses and Dissertations

Predictions of environmental conditions within the marine atmospheric surface layer (MASL) are important to X-band radar system performance. Anomalous propagation occurs in conditions of non-standard atmospheric refractivity, driven by the virtually permanent presence of evaporation ducts (ED) in marine environments. Evaporation ducts are commonly characterized by the evaporation duct height (EDH), evaporation duct strength, and the gradients below the EDH, known as the evaporation duct curvature. Refractivity, and subsequent features, are estimated in the MASL primarily using four methods: in-situ measurements, numerical weather and surface layer modeling, boundary layer theory, and inversion methods.

The existing refractivity estimation techniques often assume …


Tunable Linewidth Chip-Level Lasers Using Hybrid Integration Methods, Charles Porter 2023 Clemson University

Tunable Linewidth Chip-Level Lasers Using Hybrid Integration Methods, Charles Porter

All Theses

Photonic integrated circuits (PICs) have significant value in today’s world of research. They enable devices to experience large reductions in size, weight, operation power, and cost (SWAPc), making photonic technology more accessible than ever. The functionality of PICs is greatly enhanced due to the realization of both active and passive devices within a single device structure. This is made possible through hybrid integration, which utilizes various coupling methods to transfer light from an active chip to a passive chip. Hybrid integration technology tremendously expands the capabilities of PICs, leading to a plethora of applications. One significant application is that of …


Design And Fabrication Of An Optical Blade Tip Timing Sensor, Nick Tomlinson 2023 Clemson University

Design And Fabrication Of An Optical Blade Tip Timing Sensor, Nick Tomlinson

All Theses

Electricity is a vital energy source that powers modern technology. Turbines are heavily relied on in the electric power industry for the conversion of natural energy sources into electricity. These turbines operate under harsh conditions which increase the likelihood of blade damage. Structural health monitoring of a turbine’s blades is important to detect problems before a blade experiences failure. The blade tip timing method can be used to monitor blade vibrations and determine if damage has occurred. An optical blade tip timing sensor is designed and fabricated to advance the field of sensing in the power industry.


Miniature, Submersible Electromagnetic Pumps Of Molten Lead And Sodium For Gen-Iv Nuclear Reactors Development, Ragai M. Altamimi 2023 University of New Mexico - Main Campus

Miniature, Submersible Electromagnetic Pumps Of Molten Lead And Sodium For Gen-Iv Nuclear Reactors Development, Ragai M. Altamimi

Nuclear Engineering ETDs

Heavy metals and alkali Liquid Metals are suitable coolants for Generation IV terrestrial nuclear reactors for operating at elevated temperatures for achieving plant thermal efficiency more than 40% and the thermochemical generation of hydrogen fuel. In addition, the low vapor pressure of these liquids eliminates the need for a pressure vessel and instead operates slightly below ambient pressure. A primary issue with the uses of these coolants is their compatibility with nuclear fuel, cladding and core structure materials at elevated temperatures more than 500oC. Therefore, in pile and out-of-pile test loops have been constructed or being considered for quantifying the …


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