Electromagnetics and Photonics Commons^™

Ellipsometric Characterization Of Silicon And Carbon Junctions For Advanced Electronics, Alexander G. Boosalis

Department of Electrical and Computer Engineering: Dissertations, Theses, and Student Research

Ellipsometry has long been a valuable technique for the optical characterization of layered systems and thin films. While simple systems like epitaxial silicon dioxide are easily characterized, complex systems of silicon and carbon junctions have proven difficult to analyze. Traditional model dielectric functions for layered silicon homojunctions, a system with a similar structure to modern transistors, often have correlated parameters during ellipsometric data analysis. Similarly, epitaxial graphene as grown from thermal sublimation of silicon from silicon carbide or through chemical vapor deposition, tend to have model dielectric function parameters that correlate with the optical thickness of the graphene due to …

Scaled Synthetic Aperture Radar System Development, Ryan K. Green

Master's Theses

Synthetic Aperture Radar (SAR) systems generate two dimensional images of a target area using RF energy as opposed to light waves used by cameras. When cloud cover or other optical obstructions prevent camera imaging over a target area, SAR can be substituted to generate high resolution images. Linear frequency modulated signals are transmitted and received while a moving imaging platform traverses a target area to develop high resolution images through modern digital signal processing (DSP) techniques. The motivation for this joint thesis project is to design and construct a scaled SAR system to support Cal Poly radar projects. Objectives include …

Tungsten Disulphide Based All Fiber Q-Switching Cylindrical-Vector Beam Generation, J. Lin, K. Yan, Yong Zhou, L. X. Xu, C. Gu, Qiwen Zhan

Electro-Optics and Photonics Faculty Publications

We proposed and demonstrated an all fiber passively Q-switching laser to generate cylindrical-vectorbeam, a two dimensional material,tungsten disulphide (WS2), was adopted as a saturable absorber inside the laser cavity, while a few-mode fiber Bragg grating was used as a transverse mode-selective output coupler. The repetition rate of the Q-switching output pulses can be varied from 80 kHz to 120 kHz with a shortest duration of 958 ns. Attributed to the high damage threshold and polarization insensitivity of the WS2 based saturable absorber, the radially polarized beam and azimuthally polarized beam can be easily generated in the Q-switchingfiber laser.

A Study Of Direct Digital Manufactured Rf/Microwave Packaging, John W.I. Stratton

USF Tampa Graduate Theses and Dissertations

Various facets of direct digital manufactured (DDM) microwave packages are studied. The rippled surface inherent in fused deposition modeling (FDM) fabricated geometries is modeled in Ansoft HFSS, and its effect on the performance of microstrip transmission lines is assessed via simulation and measurement. The thermal response of DDM microstrip transmission lines is analyzed over a range of RF input powers, and linearity is confirmed over that range.

Two IC packages are embedded into DDM printed circuit boards, and their performance is analyzed. The first is a low power RF switch, and the second is an RF front end device that …

Skin Effect Suppression In Infrared-Laser Irradiated Planar Multi-Walled Carbon Nanotube/Cu Conductors, Kamran Keramatnejad, Yang Gao, Yunshen Zhou, Hossein Rabiee Glogir, Mengmeng Wang, Yongfeng Lu

Department of Electrical and Computer Engineering: Dissertations, Theses, and Student Research

Skin effect suppression in planar multi-walled carbon nanotube (MWCNT)/Copper (Cu) conductors was realized at the 0-10 MHz frequency range through infrared laser irradiation of MWCNTs, which were coated on the surface of the Cu substrate via the electrophoretic deposition (EPD) method. The effect of laser irradiation and its power density on electrical and structural properties of the MWCNT/Cu conductors was investigated using a wavelength-tunable CO2 laser and then comparing the performance of the samples prepared at different conditions with that of pristine Cu. The irradiation at λ=9.219 μm proved to be effective in selective delivery of energy towards depths close …

Industry-University Collaboration: A University Of Dayton Model, Guru Subramanyam

Electrical and Computer Engineering Faculty Publications

This paper introduces industry-university collaboration activities currently in place at the University of Dayton's School of Engineering. These collaborations are important to prepare industry-ready graduates who excel in technical, entrepreneurial, and leadership skills. One of the key curricular components is the industry-sponsored multidisciplinary projects. Industry involvement in advisory committee, strategic research partnerships, and other forms are discussed.

Negative Index In A Lossy Chiral Metamaterial Under First-Order Material Dispersion Using A Drude Model, Tarig A. Algadey, Monish Ranjan Chatterjee

Electrical and Computer Engineering Faculty Publications

Using the Drude model for complex conductivity,phase and group velocities, and indices are calculated under first-order dispersion in chiral metamaterials. Conditions are derived for negative index, and the results compared with parametric analyses.

Translation Of Rabindranath Tagore's 'Ode To Africa', Monish Ranjan Chatterjee

Electrical and Computer Engineering Faculty Publications

During his illustrious lifetime, Rabindranath Tagore travelled extensively around the world, spreading inspiration and gaining veneration in most destinations as the emissary of the East and of a deeply futuristic Universalist philosophy. An assessment of the intellectuals and cultural icons of the world whom Tagore encountered, interacted with, and influenced, is both astonishing and indeed still waiting to be adequately evaluated. His exchanges with Einstein, Wells, Rolland, Gide, Freud, Durant, Yeats, Rothenstein, Andrews, Noguchi, Gandhi, Radhakrishnan, Nehru, Bose and numerous others are well-documented. Tagore's literary works and public life centered on rejoicing in and celebrating everything unique and artistic in …

Spectral And Performance Analysis For The Propagation And Retrieval Of Signals From Modulated Chaos Waves Transmitted Through Modified Von Karman Turbulence, Fathi H.A. Mohamed, Monish Ranjan Chatterjee

Electrical and Computer Engineering Faculty Publications

A transfer function formalism is applied to track propagation of modulated chaos waves through modified von Karman phase turbulence; the demodulated signal is examined vis-à-vis performance relative to turbulence strength in comparison with non-chaotic propagation.

Creation Of Identical Multiple Focal Spots With Prescribed Axial Distribution, Yanzhong Yu, Qiwen Zhan

Electro-Optics and Photonics Faculty Publications

We present a scheme for the construction of coaxially equidistant multiple focal spots with identical intensity profiles for each individual focus and a predetermined number and spacing. To achieve this, the radiation field from an antenna is reversed and then gathered by high numerical aperture objective lenses. Radiation patterns from three types of line sources, i.e., the electric current, magnetic current and electromagnetic current distributions, with cosine-squared taper are respectively employed to generate predominately longitudinally polarized bright spots, azimuthally polarized doughnuts, and focal spots with a perfect spherically symmetric intensity distribution. The required illuminations at the pupil plane of a …

Numerical Studies And Optimization Of Magnetron With Diffraction Output (Mdo) Using Particle-In-Cell Simulations, Alireza Majzoobi

Electrical & Computer Engineering Theses & Dissertations

The first magnetron as a vacuum-tube device, capable of generating microwaves, was invented in 1913. This thesis research focuses on numerical simulation-based analysis of magnetron performance. The particle-in-cell (PIC) based MAGIC software tool has been utilized to study the A6 and the Rising-Sun magnetron structures, and to obtain the optimized geometry for optimizing the device performance. The A6 magnetron is the more traditional structure and has been studied more often. The Rising-Sun geometry, consists of two alternating groups of short and long vanes in angular orientation, and was created to achieve mode stability.

The effect of endcaps, changes in lengths …

A Study On 2.45 Ghz Bandpass Filters Fabricated With Additive Manufacturing, Nicholas Christian Arnal

USF Tampa Graduate Theses and Dissertations

Square open loop resonator (SOLR) bandpass filters fabricated with additive manufacturing techniques are presented and studied. One filter contains novel 3D capacitive plates used to enhance resonator coupling. The filters are centered at 2.45 GHz and loaded with capacitors for miniaturization as low as 21% that of a conventional SOLR bandpass filter. The pass-band insertion loss of the filters ranges from 3.8 dB to 5.5 dB and the 3 dB bandwidth ranges from 180 MHz to 250 MHz. Also, degradation in the effective conductivity of printed ink as a function of substrate roughness is analyzed. Finally, a study of dielectric …

Tailoring Optical Complex Field With Spiral Blade Plasmonic Vortex Lens, Guanghao Rui, Qiwen Zhan, Yiping Cui

Electro-Optics and Photonics Faculty Publications

Optical complex fields have attracted increasing interests because of the novel effects and phenomena arising from the spatially inhomogeneous state of polarizations and optical singularities of the light beam. In this work, we propose a spiral blade plasmonic vortex lens (SBPVL) that offers unique opportunities to manipulate these novel fields. The strong interaction between the SBPVL and the optical complex fields enable the synthesis of highly tunable plasmonic vortex. Through theoretical derivations and numerical simulations we demonstrated that the characteristics of the plasmonic vortex are determined by the angular momentum (AM) of the light, and the geometrical topological charge of …

Directional Ringlet Intensity Feature Transform For Tracking, Evan Krieger, Paheding Sidike, Theus H. Aspiras, Vijayan K. Asari

Electrical and Computer Engineering Faculty Publications

The challenges existing for current intensity-based histogram feature tracking methods in wide area motion imagery include object structural information distortions and background variations, such as different pavement or ground types. All of these challenges need to be met in order to have a robust object tracker, while attaining to be computed at an appropriate speed for real-time processing. To achieve this we propose a novel method, Directional Ringlet Intensity Feature Transform (DRIFT), that employs Kirsch kernel filtering and Gaussian ringlet feature mapping. We evaluated the DRIFT on two challenging datasets, namely Columbus Large Image Format (CLIF) and Large Area Image …

Vanadium Oxide Thin-Film Variable Resistor-Based Rf Switches, Kuanchang Pan, Weisong Wang, Eunsung Shin, Kelvin Freeman, Guru Subramanyam

Electrical and Computer Engineering Faculty Publications

Vanadium dioxide (VO2) is a unique phase change material (PCM) that possesses a metal-to-insulator transition property. Pristine VO2 has a negative temperature coefficient of resistance, and it undergoes an insulator-to-metal phase change at a transition temperature of 68°C. Such a property makes the VO2 thin-film-based variable resistor (varistor) a good candidate in reconfigurable electronics to be integrated with different RF devices such as inductors, varactors, and antennas. Series single-pole single-throw (SPST) switches with integrated VO2 thin films were designed, fabricated, and tested. The overall size of the device is 380 μm × 600 μm. The SPST switches were fabricated on …

Miniaturized Wideband Planar Soft Surfaces For Mutual Coupling Reduction Between Antenna Elements, Said A. Abushamleh

Theses and Dissertations

Miniaturized electromagnetic soft surfaces have promising applications in contemporary wideband portable wireless devices including, Multiple Input Multiple Output (MIMO) systems, dual frequency applications, and mutual coupling reduction among antennas in user terminals utilizing MIMO schemes such as in 4th generation Long-Term Evolution (4G-LTE). The use of textured metallic surfaces over grounded dielectric slab with vias for the suppression of electromagnetic wave propagation for applications including, but not limited to, mutual coupling reduction among closely-spaced antenna elements in antenna arrays, bandwidth enhancement, and gain enhancement has been extensively researched during the past two decades. In this dissertation, novel one-dimensional (1-D) periodic …

Experimental Design And Construction For Critical Velocity Measurement In Spin-Orbit Coupled Bose-Einstein Condensates, Ting-Wei Hsu, Yong P. Chen

The Summer Undergraduate Research Fellowship (SURF) Symposium

Quantum simulation using ultra-cold atoms, such as Bose-Einstein Condensates (BECs), offers a very flexible and well controlled environment to simulate physics in different systems. For example, to simulate the effects of spin orbit coupling (SOC) on electrons in solid state systems, we can make a SOC BEC which mimics the behavior of SOC electrons. The goal of this project is to see how the superfluid property of BECs change in the presence of SOC. In particular, we plan to measure the critical velocity of an 87Rb BEC with and without SOC by stirring it with a laser. This laser needs …

Simulation Design For Photovoltaics Using Finite Difference Time Domain And Quadratic Complex Rational Function Methods, Jacob R. Duritsch, Haejun Chung, Peter Bermel

The Summer Undergraduate Research Fellowship (SURF) Symposium

Photovoltaics (PV) can in principle supply enough renewable energy to offset a great deal of fossil fuel usage. To achieve this transition, it is critical to develop improved PV cells with decreased material costs and improved efficiencies. This goal can be greatly facilitated by a tool simulating the absorption and efficiency of experimentally relevant 3-D PV designs made of realistic materials, including those that have not yet been discovered. By incorporating the quadratic complex rational function algorithm (QCRF) with the finite difference time domain methods (FDTD), simulations can include frequency response and optical properties, while allowing full customization of tandem …

Mass-Positioning Of Nanodiamonds Using Squeegee Technique, Ran Cui, Mikhail Y. Shalaginov, Vladimir M. Shalaev

The Summer Undergraduate Research Fellowship (SURF) Symposium

Fluorescent color centers in diamond nanocrystals have recently become the focus of researchers because of their potential applications in quantum information processing, nano-sensing, biomarking, and bioimaging. One of the biggest challenges in working with nanodiamonds is how to position them precisely and efficiently to create strong interaction with nanoscale photonic structures. The most popular methods to position nanodiamonds are spin-coating and transporting via scanning probe microscope tip. On the one hand, spin-coating, where nanodiamonds are randomly located, is not precise; on the other hand, the tip-based technique, where a single nanodiamond is picked and dropped, is tedious and time-consuming. Hence, …

Simplified Generation Of The Input Models Of Object Oriented Micromagnetic Framework (Oommf), Jinyang Yu, Rafatul Faria, Supriyo Datta, Tanya A. Faltens

The Summer Undergraduate Research Fellowship (SURF) Symposium

Object Oriented MicroMagnetic Framework (OOMMF) is a micromagnetic simulation tool. It takes a memory initialization file (MIF) as the input and outputs various forms of data such as data table, graph and magnetic configuration plots. It is accurate and fast compared to other existing tools such as MATLAB. Few experimentalists used it in the past, however, due to two main reasons. First, OOMMF requires a specific version of programming environment on the local computer which is difficult to be installed. Second, MIF file is very complicated to code and it also requires users to read a lengthy guidelines. Our solution …

Creation Of Carbon Nanotube Based Biosensors Through Dielectrophoretic Assembly, Nilan S. Mani, Steve Kim, Kaushik Annam, Danielle Bane, Guru Subramanyam

Electrical and Computer Engineering Faculty Publications

Due to their excellent electrical, optical, and mechanical properties, nanosized single wall carbon nanotubes (SWNTs) have attracted significant attention as a transducing element in nano-bio sensor research. Controlled assembly, device fabrication, and bio-functionalization of the SWNTs are crucial in creating the sensors. In this study, working biosensor platforms were created using dielectrophoretic assembly of single wall carbon nanotubes (SWNTs) as a bridge between two gold electrodes. SWNTs in a commercial SDS surfactant solution were dispensed in the gap between the two gold electrodes, followed by applying an ac voltage across the two electrodes. The dielectrophoresis aligns the CNTs and forms …

Automatic Registration Of Optical Aerial Imagery To A Lidar Point Cloud For Generation Of City Models, Bernard Olushola Abayowa, Alper Yilmaz, Russell C. Hardie

Electrical and Computer Engineering Faculty Publications

This paper presents a framework for automatic registration of both the optical and 3D structural information extracted from oblique aerial imagery to a Light Detection and Ranging (LiDAR) point cloud without prior knowledge of an initial alignment. The framework employs a coarse to fine strategy in the estimation of the registration parameters. First, a dense 3D point cloud and the associated relative camera parameters are extracted from the optical aerial imagery using a state-of-the-art 3D reconstruction algorithm. Next, a digital surface model (DSM) is generated from both the LiDAR and the optical imagery-derived point clouds. Coarse registration parameters are then …

Dna Based Electrolyte/Separator For Lithium Battery Application, Jitendra Kumar, Fahima Ouchen-Bouchendouka, Devin A. Smarra, Guru Subramanyam, James Grote

Electrical and Computer Engineering Faculty Publications

In this study, we demonstrated the use of DNA-CTMA (DC) in combination with PolyVinylidene Fluoride (PVDF) as a host matrix or separator for Lithium based electrolyte to form solid polymer/gel like electrolyte for potential application in Li-ion batteries.

The addition of DC provided a better thermal stability of the composite electrolyte as shown by the thermos-gravimetric analysis (TGA). The AC conductivity measurements suggest that the addition of DC to the gel electrolyte had no effect on the overall ionic conductivity of the composite. The obtained films are flexible with high mechanical stretch-ability as compared to the gel type electrolytes only.

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).

Secure Transmission And Retrieval Of Images In Conjunction With Steganography Using Chaos In Nonlinear Acousto-Optic Feedback, Monish Ranjan Chatterjee, Fares S. Almehmadi

Electrical and Computer Engineering Faculty Publications

Digital images are encrypted onto a chaotic carrier in a Bragg cell under hybrid nonlinear feedback and secure data is embedded into the system via steganography. System robustness (with and without channel noise) is analyzed vis-a-vis information security.

Towards Circularly Polarized Reconfigurable Huygens Source, Adam Narbudowicz, Max Ammann, Dirk Heberling

Conference papers

The paper investigates an array of two reconfigurable circularly-polarized antennas with omnidirectional radiation pattern. The results are based on a previously reported antenna, which offers a steerable dipolelike radiation pattern. Its capabilities allow reception of a signal from practically any direction with steering realized by rotation of the pattern around a single axis. In this paper we propose to extend this functionality by forming an array of two such antennas oriented as a Huygens source. Simulations demonstrate six distinctive radiation patterns, each illuminating a different sector of the surrounding sphere. This allows increased antenna gain and simplification of the steering …

Planar Dual-Mode Mimo Antenna With Enhanced Bandwidth, Adam Narbudowicz, Slawomir Koziel, Max Ammann, Dirk Heberling

Conference papers

The paper proposes a dual-port pa MIMO applications, optimized using optimization techniques. The antenna uses two (TM100 and TM200) to generate two indep patterns. To enhance the bandwidth of TM200 ground plane was realized as a meshed surfac approach provides 97 MHz of bandwidth, while profile of 1.5 mm between the patch and the g 3.5). The numerical optimization involved 12 adj parameters.

Fabrication Of Sub-10 Nm Metallic Structures Via Nanomasking Technique For Plasmonic Enhancement Applications, Stephen Joseph Bauman

Graduate Theses and Dissertations

One area of nanoscience that has become popular in recent years is the study of optics at the nanoscale. Due to enhanced fabrication techniques, new geometries and improved dimensional resolutions have been allowing the creation of nanostructures for use in this area. Nanoscale geometries cause unique optical effects such as enhancement of the signal’s electric field strength at the surface of a substrate. Specifically, structures separated by nanogaps (10 nm and smaller) have been shown to exhibit strong field enhancement within the gaps. This has opened up the potential for surface enhanced spectroscopies, enhanced absorption for photovoltaics, and improved sensing …

Numerical Simulation Of Terahertz Wave Interaction With Breast Cancer Tumor Tissue Sections, Abayomi Omotola Omolewu

Graduate Theses and Dissertations

This thesis presents numerical simulation of terahertz (THz) wave interaction with breast cancer tumor tissue sections. The obtained results are expressed in THz images of heterogeneous material that mimics the excised breast cancer tissue sections. The finite-element software package ANSYS High Frequency Structural Simulator (HFSS) was used in this work. HFSS is a full wave frequency domain three-dimensional (3D) electromagnetic simulation package. In this work, four breast cancer tissue models based on pathology images were simulated and images of the models were obtained at 1 THz. An incident Gaussian beam was raster scanned over tissue model configurations and the reflected …

The Effects Of Strain And Vacancies On The Electric And Vibrational Properties Of Ferroelectric Batio3 From First-Principles, Aldo Serge Michael Raeliarijaona

Graduate Theses and Dissertations

The studies of ferroelectricity (FE) are of technological significance because of the multitude of applicable properties that ferroelectric materials exhibit. The mastery, and control of these properties necessitate the knowledge of the fundamental physics governing these insulating materials.

In this dissertation I present the results of first-principles investigations of the behavior of the fundamental ferroelectric properties under strain, and in the presence of vacancies. In the first part I introduce the important FE properties, their common behavior, and their numerous valuable applications. Following this background on FEs, a review of theoretical methods is presented with topics such as: Density Functional …