Electromagnetics and Photonics Commons^™

Development Of Rigorous Electromagnetic Simulation Tools For Anisotropic Structures, Jose Luis Enriquez

Open Access Theses & Dissertations

Many times, mankind's creative nature has pushed the envelope beyond what was deemed physically possible at the time. People have engineered ways for us to fly, communicate across the globe in seconds, landed on the moon, and more recently discovered ways to make an object invisible. Unfortunately, there are times that this creativeness is hindered by funding, access to required tools or a combination of both. While this work cannot provide funding, it does provide a tool that one could use to model and simulate a variety of media. The media can vary from devices already being implemented to more …

The Development Of Near Field Probing Systems For Emc Near Field Visualization And Emi Source Localization, Hui He

Masters Theses

"The objectives of this research are to visualize the frequency dependent electromagnetic field distribution for electromagnetic compatibility (EMC) applications and the radiating source reconstruction on complex shaped electronic systems. This is achieved by combining near field probing with a system for automatically recording the probe position and orientation. Due to the complexity of the shape of the electronic systems of interest, and for utilizing the expertise of the user, the probe will be moved manually not robotically. Concurrently, the local near field will be recorded, associated with the location and displayed at near real time on the captured 3D geometry …

Modeling And Preliminary Characterization Of Passive, Wireless Temperature Sensors For Harsh Environment Applications Based On Periodic Structures, Diego Ivan Delfin Manriquez

Open Access Theses & Dissertations

Wireless temperature sensing has attained significant attention in recent years due to the increasing need to develop reliable and affordable sensing solutions for energy conversion systems and other harsh environment applications. The development of next generation sensors for energy production processing parameters, such as temperature and pressure, can result in better performance of the system. Particularly, continuous temperature monitoring in energy conversion systems can result in enhancements such as better system integrity, less pollution and higher thermal efficiencies. However, the conditions experienced in these system components hinder the performance of current solutions due to the presence of semi-conductor materials and …

Contactless Measurement Of Angular Velocity Using Circularly Polarized Antennas, Vit Sipal, Adam Narbudowicz, Max Ammann

Articles

An innovative method to measure the angular velocity using circularly polarized antennas is proposed. Due to the properties of circular polarization, the angular velocity is frequency modulated (FM) on a wireless carrier. This enables a low-cost precise continuous measurement of angular velocity using a standard FM demodulator. The hardware can be easily adapted for both high and low angular velocity values. The precise alignment angle between the antennas can be determined if the initial antenna orientation is known. The angular error is shown to be

Impact Of Hub Location On The Performance Of Wireless Body Area Networks For Fitness Applications, Vit Sipal, Domenico Gaetano, Patrick Mcevoy, Max Ammann

Articles

This letter compares the propagation properties of Wireless Body Area Networks for three different locations (head, foot and waist) of the hub/internet gateway on the human body. The wireless channels between the hubs and four nodes (chest, back, and upper arms) are measured on a female and a male subject performing push-ups and squats. A framework using spider plots is used for cumulative performance description. The results show that the best overall performance is for hub located on the left temple and the worst overall performance is achieved for a hub on the waist. These results are expected to stimulate …

Nanopulse Generators: Their Design And Application To Cancer Therapy Studies, Daniel P. Wernig

Senior Honors Theses

Effective nanopulse generators have become critical in recent decades concerning the study of subcellular affects in response to nanosecond pulsed electric fields. It has been observed that nanosecond duration electric pulses can target intracellular organelles, ultimately leading to cell apoptosis, suggesting the possibility of a new, minimally invasive, low risk cancer therapy methodology. The standard topology for developing a medical nanopulser is the Blumlein “transmission line” approach. This approach relies on the nearly infinitesimal, yet finite amount of time required for an electromagnetic field to propagate down a short transmission line. Prior to design, requirements and constraints must be defined …

Improved Performance Of Analog And Digital Acousto-Optic Modulation With Feedback Under Profiled Beam Propagation For Secure Communication Using Chaos, Fares S. Almehmadi, Monish Ranjan Chatterjee

Electrical and Computer Engineering Faculty Publications

Using intensity feedback, the closed-loop behavior of an acousto-optic hybrid device under profiled beam propagation has been recently shown to exhibit wider chaotic bands potentially leading to an increase in both the dynamic range and sensitivity to key parameters that characterize the encryption. In this work, a detailed examination is carried out vis-à-vis the robustness of the encryption/decryption process relative to parameter mismatch for both analog and pulse code modulation signals, and bit error rate (BER) curves are used to examine the impact of additive white noise.

The simulations with profiled input beams are shown to produce a stronger encryption …

Split-Step Approach To Electromagnetic Propagation Through Atmospheric Turbulence Using The Modified Von Karman Spectrum And Planar Apertures, Monish Ranjan Chatterjee, Fathi H.A. Mohamed

Electrical and Computer Engineering Faculty Publications

The impact of atmospheric phase turbulence on Gaussian beam propagation along propagation paths of varying lengths is examined using multiple random phase screens. The work is motivated by research involving generation and encryption of acousto-optic chaos, and the interest in examining propagation of such chaotic waves through atmospheric turbulence. A phase screen technique is used to simulate perturbations to the refractive index of the medium through the propagation path. A power spectral density based on the modified von Karman spectrum model for turbulence is used to describe the random phase behavior of the medium.

In recent work, results for the …

Photoelectric Characterization Of Bacteriorhodopsin Reconstituted In Lipid Bilayer Membrane, Joel Kamwa

Graduate Theses and Dissertations

The objective of this work was to conduct basic research in biologically inspired energy conversion solutions. A photosynthetic protein (Bacteriorhodopsin) was reconstituted in a bi-layer membrane. Then, when a laser beam was shined on the membrane, the photon energy was used by the protein to pump protons across the membrane. The translocation of protons across the membrane was measured as photocurrent. For this purpose, a system was built to characterize the lipid bilayer membranes and to measure the photocurrent. The lipid bilayer membrane was characterized by its capacitance and resistance. A picoampere photocurrent was observed when Bacteriorhodopsin protein was present …

Life Cycle Assessment Projection Of Photovoltaic Cells: A Case Study On Energy Demand Of Quantum Wire Based Photovoltaic Technology Research, Shilpi Mukherjee

Graduate Theses and Dissertations

With increasing clean-energy demand, photovoltaic (PV) technologies have gained attention as potential long-term alternative to fossil fuel energy. However, PV research and manufacture still utilize fossil fuel-powered grid electricity. With continuous enhancement of solar conversion efficiency, it is imperative to assess whether overall life cycle efficiency is also being enhanced. Many new-material PV technologies are still in their research phase, and life cycle analyses of these technologies have not yet been performed. For best results, grid dependency must be minimized for PV research, and this can be accomplished by an analytical instrument called Life Cycle Assessment (LCA).

LCA is the …

Shaping The Axial-Ratio Footprint Of Crossed-Dipole Antennas, Adam Narbudowicz, Max Ammann, Janusz Przewocki

Conference papers

A method is proposed to adaptively change the axial-ratio beam of simple circularly-polarized antennas. It is shown, that by varying the phase shift between two orthogonal elements the axial-ratio beam shape can be dynamically adjusted. This allows control of the direction of minimum axial-ratio and the ability to increase or decrease the beamwidth in one of two planes. The method is intended for satellite navigation systems: it can improve the rejection of reflected signals in varying propagation conditions (e.g. urban canyons), while using simple and low-cost circularly-polarized antennas.

Microwave Chemical Sensing Using Overmoded T-Line Designs And Impact Of Real-Time Digitizer In The System, Yu-Ting Huang

Open Access Dissertations

Microwave spectrometers have unique advantages in the ability to determine high resolution features that are specific to a given chemical. Very sharp lines which correspond to quantum states of the chemical allow for unique identification of the chemical. Recent advances have shown the possibility of room temperature microwave spectroscopy analysis in which the data is collected in a short amount of time using broadband chirp pulse Fourier transform microwave (CP-FTMW) spectroscopy. In this report, we explore the design of reduced size spectrometers focusing on the reduction as well as expansion of operation frequency of the microwave analysis cell, where the …

Nuclear Magnetic Resonance Studies On Lithium And Sodium Electrode Materials For Rechargeable Batteries, Tetiana Nosach

Dissertations, Theses, and Capstone Projects

In this thesis, Nuclear Magnetic Resonance (NMR) spectroscopic techniques are used to study lithium and sodium electrode materials for advanced rechargeable batteries. Three projects are described in this thesis. The first two projects involve 6Li, 7Li and 31P NMR studies of two cathode materials for advanced rechargeable batteries. The third project is a study of sodium titanate cathode materials for Na-ion batteries, where 1H, 7Li, and 23Na static and magic angle spinning NMR were used in order to obtain detailed information on the chemical environments.

Numerical Studies Of The A6 Relativistic Magnetron Using Particle-In-Cell Simulations, Vineetha Jujjavarapu

Electrical & Computer Engineering Theses & Dissertations

The magnetron became a major component in radar systems around the time of the World War II. More recent radar techniques require short microwave pulses (with nanosecond pulse-widths for ultra wideband operations) and high peak power in the Giga-Watt range. In order to achieve these specifications for the military, the magnetron needs to have both a fast start and the rapid growth rate of oscillations in order to serve as a microwave source for the short-pulse applications. These two factors depend on the geometry of the cathode. Other requirements include high conversion efficiency and low leakage current (in order to …

Hyperfine Interactions In The Electron Paramagnetic Resonance Spectra Of Point Defects In Wide-Band-Gap Semiconductors, Eric M. Golden

Theses and Dissertations

The focus of this research was to acquire definitive experimental data on predominant point defects in three important wide-band-gap semiconductors. Hyperfine interactions in electron paramagnetic resonance spectra were used to characterize the neutral nitrogen acceptor in zinc oxide, to identify a silicon interstitial impurity in titanium dioxide, and to determine the electronic structure of the singly ionized sulfur vacancy in stannous hexathiohypodiphosphate (SPS). Research on the basic properties of these technologically important materials plays a crucial role in the development of advanced optical and electronic systems. Zinc oxide is an electro-optic material with the potential to produce high performance electronics …

Hybrid Silicon Mode-Locked Laser With Improved Rf Power By Impedance Matching, Bassem M. Tossoun

Master's Theses

The mode-locked laser diode (MLLD) finds a lot of use in applications such as ultra high-speed data processing and sampling, large-capacity optical fiber communications based on optical time-division multiplexing (OTDM) systems. Integrating mode-locked lasers on silicon makes way for highly integrated silicon based photonic communication devices. The mode-locked laser being used in this thesis was built with Hybrid Silicon technology. This technology, developed by UC Santa Barbara in 2006, introduced the idea of wafer bonding a crystalline III- V layer to a Silicon-on-insulator (SOI) substrate, making integrated lasers in silicon chips possible.

Furthermore, all mode-locked lasers produce phase noise, which …

First Demonstration Of Ultra-Thin Sige-Channel Junctionless Accumulation-Mode (Jam) Bulk Finfets On Si Substrate With Pn Junction-Isolation Scheme, Donghyun Kim, Tae Kyun Kim, Young Gwang Yoon, Byeong Woon Hwang, Yang-Kyu Choi, Byung Jin Cho, Seok-Hee Lee

Electrical and Computer Engineering Faculty Research & Creative Works

A SiGe-channel junctionless-accumulation-mode (JAM) PMOS bulk FinFETs were successfully demonstrated on Si substrate with PN junction-isolation scheme for the first time. The JAM bulk FinFETs with fin width of 18 nm exhibits excellent subthreshold characteristics such as subthreshold swing of 64 mV/decade, drain-induced barrier lowering (DIBL) of 40 mV/V and high I_on/I_off current ratio ( > 1 x 10⁵). The change of substrate bias from 0 to 5 V leads to the threshold voltage shift of 53 mV by modulating the effective channel thickness. When compared to the Si-channel bulk FinFETs with fin width of 18 …

Health Risks Caused By Wireless Technologies, Durreeshahwar Zafarahmed, Qurrat-Ul-Ain Zafarahmed

Journal of Undergraduate Research at Minnesota State University, Mankato

There are many health issues related to the use of cellular phones, wireless local area networks, and other devices that emit electromagnetic radiation (EMR). Some of these systems have become a part of our daily lives and many of us are in direct or indirect contact for extended period of times with these devices. However, the general public is unaware of the health risks associated with the use of these devices. Our research covers studies done by individuals as well as organizations on the harmful effects on the health of people from these devices and their claims. We also present …

Optical Resonators And Fiber Tapers As Transducers For Detection Of Nanoparticles And Bio-Molecules, Huzeyfe Yilmaz

McKelvey School of Engineering Graduate Student Theses & Dissertations

In recent years, detection of biological interactions on single molecule level has aspired many researchers to investigate several optical, chemical, electrical and mechanical sensing tools. Among these tools, toroidal optical resonators lead the way in detection of the smallest particle/molecule with the real time measurements. In this work, bio-sensing capabilities of toroidal optical resonators are investigated. Bio-sensing is realized via measuring the analyte-antigen interaction while the antigen is immobilized through a novel functionalization method.

Not long ago, detection of single nanoparticles using optical resonators has been accomplished however the need for cost-effective and practical transducers demands simpler tools. A tapered …

Simulation Of Plasmonic Waveguides Based On Long-Range Surface Plasmon Polaritons, Yugang Jing, Alexandra Boltasseva, Nathaniel Kinsey

The Summer Undergraduate Research Fellowship (SURF) Symposium

The demand for faster and smaller computing devices is growing larger and larger. In the recent decade, research has proven that plasmonic devices have exciting characteristics and performance for next generation on‑chip structures. However, most of these devices contain noble metals and are not CMOS compatible. This work numerically investigates the performance of plasmonic waveguide designs made of TiN, a CMOS compatible material with optical properties similar to gold. Through our work, we demonstrate that TiN nanophotonic devices can be useful for inter-chip connections. A series of simulations using COMSOL Multiphysics were performed to test the performance of these structures. …