Open Access. Powered by Scholars. Published by Universities.®

Electromagnetics and Photonics Commons

Open Access. Powered by Scholars. Published by Universities.®

2228 Full-Text Articles 2998 Authors 457895 Downloads 58 Institutions

All Articles in Electromagnetics and Photonics

Faceted Search

2228 full-text articles. Page 4 of 67.

Kasi: A Ka-Band And S-Band Cross-Track Interferometer, Gerard Ruiz Carregal 2017 University of Massachusetts Amherst

Kasi: A Ka-Band And S-Band Cross-Track Interferometer, Gerard Ruiz Carregal

Masters Theses

A dual-frequency system is needed to better understand natural processes that constitute the environment and seasonal cycles of the Earth. A system working at two different wavelengths acquiring data simultaneously will give a valuable dataset since the conditions on the ground will be exactly the same. Hence, elements such as wind, soil moisture or any other changes on the ground will not interfere in the mea- surements. This thesis explains how an S-band radar was built and tested. Moreover, the experiments done with a Ka-band radar used as a scatterometer are explained as well as the data processing and analysis ...


Analyses Of Densely Crosslinked Phenolic Systems Using Low Field Nmr, Jigneshkumar Patel 2017 University of Massachusetts, Amherst

Analyses Of Densely Crosslinked Phenolic Systems Using Low Field Nmr, Jigneshkumar Patel

Doctoral Dissertations

A uniform dispersion of reactants is necessary to achieve a complete reaction involving multi-components, especially for the crosslinking of rigid high-performance materials. In these reactions, miscibility is crucial for curing efficiency. This miscibility is typically enhanced by adding a third component, a plasticizer. For the reaction of the highly crystalline crosslinking agent hexamethylenetetramine (HMTA) with a strongly hydrogen-bonded phenol formaldehyde resin, furfural has been traditionally used as the plasticizer. However, the reason for its effectiveness is not clear. In this doctoral thesis work, miscibility and crosslinking efficiency of plasticizers in phenolic curing reactions are studied by thermal analysis and spectroscopic ...


Nist Microwave Blackbody: The Design, Testing, And Verification Of A Conical Brightness Temperature Source, Derek Anderson Houtz 2017 University of Colorado at Boulder

Nist Microwave Blackbody: The Design, Testing, And Verification Of A Conical Brightness Temperature Source, Derek Anderson Houtz

Aerospace Engineering Sciences Graduate Theses & Dissertations

Microwave radiometers allow remote sensing of earth and atmospheric temperatures from space, anytime, anywhere, through clouds, and in the dark. Data from microwave radiometers are high-impact operational inputs to weather forecasts, and are used to provide a vast array of climate data products including land and sea surface temperatures, soil moisture, ocean salinity, cloud precipitation and moisture height profiles, and even wind speed and direction, to name a few. Space-borne microwave radiometers have a major weakness when it comes to long-term climate trends due to their lack of traceability. Because there is no standard, or absolute reference, for microwave brightness ...


Suppression Of Magnetostructural Transition On Gdsige Thin Film After Thermal Cyclings, A. L. Pires, J. H. Belo, I. T. Gomes, Ravi L. Hadimani, Deborah L. Schlagel, Thomas A. Lograsso, David C. Jiles, A. M. L. Lopes, J. P. Araújo, A. M. Pereira 2017 Universidade do Porto

Suppression Of Magnetostructural Transition On Gdsige Thin Film After Thermal Cyclings, A. L. Pires, J. H. Belo, I. T. Gomes, Ravi L. Hadimani, Deborah L. Schlagel, Thomas A. Lograsso, David C. Jiles, A. M. L. Lopes, J. P. Araújo, A. M. Pereira

Ames Laboratory Publications

The influence of thermal cycling on the microstructure, magnetic phase transition and magnetic entropy change of a Gd5Si1.3Ge2.7 thin film up to 1000 cycles is investigated. The authors found that after 1000 cycles a strong reduction of the crystallographic phase responsible for the magnetostructural transition (Orthorhombic II phase) occurs. This is attributed to chemical disorder, caused by the large number of expansion/compression cycles that the Orthorhombic II phase undergoes across the magnetostructural transition. The suppression of the magnetostructural transition corresponds to a drastic decrease of the thin film magnetic entropy change. These results reveal the importance of ...


Electromagnetic Signal Feedback Control For Proximity Detection Systems, Adam K. Smith 2017 Michigan Technological University

Electromagnetic Signal Feedback Control For Proximity Detection Systems, Adam K. Smith

Dissertations, Master's Theses and Master's Reports

Coal is the most abundant fossil fuel in the United States and remains an essential source of energy. While more than half of coal production comes from surface mining, nearly twice as many workers are employed by underground operations.

One of the key pieces of equipment used in underground coal mining is the continuous mining machine. These large and powerful machines are operated in confined spaces by remote control. Since 1984, 40 mine workers in the U. S. have been killed when struck or pinned by a continuous mining machine. It is estimated that a majority of these accidents could ...


Advanced Liquid Crystal Displays With Supreme Image Qualities, Haiwei Chen 2017 University of Central Florida

Advanced Liquid Crystal Displays With Supreme Image Qualities, Haiwei Chen

Electronic Theses and Dissertations

Several metrics are commonly used to evaluate the performance of display devices. In this dissertation, we analyze three key parameters: fast response time, wide color gamut, and high contrast ratio, which affect the final perceived image quality. Firstly, we investigate how response time affects the motion blur, and then discover the 2-ms rule. With advanced low-viscosity materials, new operation modes, and backlight modulation technique, liquid crystal displays (LCDs) with an unnoticeable image blur can be realized. Its performance is comparable to an impulse-type display, like cathode ray tube (CRT). Next, we propose two novel backlight configurations to improve an LCD ...


Mode Evolution In Fiber Based Devices For Optical Communication Systems, Bin Huang 2017 University of Central Florida

Mode Evolution In Fiber Based Devices For Optical Communication Systems, Bin Huang

Electronic Theses and Dissertations

Space division multiplexing (SDM) is the most promising way of increasing the capacity of a single fiber. To enable the few mode fiber (FMF) or multi-mode fiber (MMF) transmission system, several major challenges have to be overcome. One is the urgent need of ideal mode multiplexer, the second is the perfect amplification for all spatial modes, another one is the modal delay spread (MDS) due to group velocity difference of spatial modes. The main subject of this dissertation is to model, fabricate and characterize the mode multiplexer for FMF transmission. First, we designed a novel resonant mode coupler (structured directional ...


High Dynamic Range Display Systems, Ruidong Zhu 2017 University of Central Florida

High Dynamic Range Display Systems, Ruidong Zhu

Electronic Theses and Dissertations

High contrast ratio (CR) enables a display system to faithfully reproduce the real objects. However, achieving high contrast, especially high ambient contrast (ACR), is a challenging task. In this dissertation, two display systems with high CR are discussed: high ACR augmented reality (AR) display and high dynamic range (HDR) display. For an AR display, we improved its ACR by incorporating a tunable transmittance liquid crystal (LC) film. The film has high tunable transmittance range, fast response time, and is fail-safe. To reduce the weight and size of a display system, we proposed a functional reflective polarizer, which can also help ...


Noise, Stability, And Linewidth Performance Of 10-Ghz Optical Frequency Combs Generated From The Nested Cavity Architecture, Kristina Bagnell 2017 University of Central Florida

Noise, Stability, And Linewidth Performance Of 10-Ghz Optical Frequency Combs Generated From The Nested Cavity Architecture, Kristina Bagnell

Electronic Theses and Dissertations

Optical frequency combs with wide mode spacing and low timing jitter are relied upon for both time domain and frequency domain applications. It has been previously demonstrated that surrounding a low-Q semiconductor laser chip with a long external fiber cavity and inserting a high finesse Fabry–Pérot etalon into this cavity can produce a mode-locked laser with the desired high repetition rate and narrow optical mode linewidths which are of benefit to applications like photonic analog-to-digital conversion and astronomical spectrograph calibration. With this nested cavity architecture, the quality factor of the resonator is effectively determined by the product of the ...


Polymer Waveguide Manufacturing And Printed Circuit Board Integration, Brandon Swatowski 2017 Michigan Technological University

Polymer Waveguide Manufacturing And Printed Circuit Board Integration, Brandon Swatowski

Dissertations, Master's Theses and Master's Reports

In this age of ever increasing data rates in communication systems, optics are becoming more commonplace for long length (>10m) signal transmission in High Performance Computing (HPC) systems due to their bandwidth capabilities which are higher than their electrical counterparts. In these optical based communication systems, Vertical Cavity Surface Emitting Lasers (VCSELs) are the most commonly used communications lasing medium for multimode fiber applications. These lasers are active in the 850 nm region, with speeds commonly at 10 Gbps/channel. VCSEL vendors are now commercializing lasers at 25 Gbps/channel as well, with research groups actively pursuing rates beyond 40 ...


A Physics-Based Approach For Power Integrity In Multi-Layered Pcbs, Biyao Zhao 2017 Missouri University of Science and Technology

A Physics-Based Approach For Power Integrity In Multi-Layered Pcbs, Biyao Zhao

Masters Theses

"Developing a power distribution network (PDN) for ASICs and ICs to achieve the low-voltage ripple specifications for current digital designs is challenging with the high-speed and low-voltage ICs. Present methods are typically guided by best engineering practices for low impedance looking into the PDN from the IC. A pre-layout design methodology for power integrity in multi-layered PCB PDN geometry is proposed in the thesis. The PCB PDN geometry is segmented into four parts and every part is modelled using different methods based on the geometry details of the part. Physics-based circuit models are built for every part and the four ...


Engineering Of Photo-Rechargeable Energy Storage, Ashim Gurung 2017 South Dakota State University

Engineering Of Photo-Rechargeable Energy Storage, Ashim Gurung

Theses and Dissertations

Solar photovoltaics (PV) is a very promising renewable energy technologies as it is abundant and pollution-free. However, the major drawback of PV power is its intermittency. Integration of batteries with solar modules can reduce overall PV system costs and increase the practicality of PV power. Integration of the photovoltaic cells with supercapacitor storage proved feasibility of combined photovoltaic energy generation and storage but the supercapacitors had low energy storage capacity. Photovoltaic cells with integrated Li-ion batteries as energy storage were demonstrated but had a complex structure due to multiple PV cells; low efficiency due to a mismatch between the PV ...


Study And Implementation Of Wideband Bow-Tie Antennas, Md Rakibul Islam 2017 Georgia Southern University

Study And Implementation Of Wideband Bow-Tie Antennas, Md Rakibul Islam

Electronic Theses & Dissertations

Demand for multifunctional electronic devices is increasing in modern wireless communication systems. As the antenna plays a vital role in wireless communication, the need to design antennas which will provide better performance and more reliable communication is growing. In this thesis, innovative designs for antennas with wideband characteristic have been proposed to meet the demands of current multi-functional wireless communication systems. First, this thesis explores the design of a wideband pattern reconfigurable antenna with steady realized gain over the operating bandwidth. Another novel design of this thesis work is a highly directive wideband Yagi antenna. Finally, a two-planar structured CPLPDA ...


Development Of Active Microwave Thermography For Structural Health Monitoring, Ali Foudazi 2017 Missouri University of Science and Technology

Development Of Active Microwave Thermography For Structural Health Monitoring, Ali Foudazi

Doctoral Dissertations

"Active Microwave Thermography (AMT) is an integrated nondestructive testing and evaluation (NDT&E) method that incorporates aspects of microwave NDT and thermography techniques. AMT uses a microwave excitation to generate heat and the surface thermal profile of the material or structure under test is subsequently measured using a thermal camera (or IR camera). Utilizing a microwave heat excitation provides advantages over traditional thermal excitations (heat lamps, etc.) including the potential for non-contact, selective and focused heating. During an AMT inspection, two heating mechanisms are possible, referred to as dielectric and induction heating. Dielectric heating occurs as a result of the ...


Modal Based Bga Modeling In High-Speed Package, Shuai Jin 2017 Missouri University of Science and Technology

Modal Based Bga Modeling In High-Speed Package, Shuai Jin

Doctoral Dissertations

"In the Section 1, the improved "Root-Omega" method for extracting dielectric properties from fabricated multilayer printed circuit boards is proposed. Based on the electrical properties of fabricated transmission lines, the improved "Root-Omega" method applied to cases with smooth and rough conductors is validated using simulations. Error sensitivity analysis is performed to demonstrate the potential errors in the original "Root-Omega" procedure and the error sensitivity is significantly reduced by the proposed improvements.

In the Section 2, a fast modal-based approach is developed to accurately and efficiently capture the proximity effect. Image theory is also applied in the proposed approach to reduce ...


Generating Fast And Accurate Compliance Reports For Various Data Rates, Srinath Penugonda 2017 Missouri University of Science and Technology

Generating Fast And Accurate Compliance Reports For Various Data Rates, Srinath Penugonda

Masters Theses

"As the demands on the industry data rates have increased there is a need for interoperable interfaces to function flawlessly. Added to this complexity, the number of I/O data lines are also increasing making it more time consuming to design and test. This in general leads to creating of compliance standards to which interfaces must adhere. The goal of this theses is to aid the Signal Integrity Engineers with a better and fast way of rendering a full picture of the interface compliance parameters.

Three different interfaces at various data rates were chosen. They are: 25Gbps Very Short Reach ...


Literature Review On Organic Materials For Third Harmonic Optical And Photonic Applications., Sreeramana Aithal, Shubhrajyotsna Aithal 2016 Selected Works

Literature Review On Organic Materials For Third Harmonic Optical And Photonic Applications., Sreeramana Aithal, Shubhrajyotsna Aithal

P. Sreeramana Aithal

The third harmonic optical applications such as optical phase conjugation, image processing, optical
switching, and optical limiting in Photonics requires efficient nonlinear optical materials to be used with low
power laser beams. During the last three decades, organic molecules have attracted the attention of many
researchers due to their high nonlinear optical susceptibility and the possibility of tailoring their properties
suitable to be used to protect optical detection components and devices such as human eyes and optical sensors,
by controlling the output energy on the image plane below the desired level. Extensive studies have been
performed and reported for the ...


Scatterometry Of 50 Nm Half Pitch Features, ruichao zhu 2016 university of new mexico

Scatterometry Of 50 Nm Half Pitch Features, Ruichao Zhu

Optical Science and Engineering ETDs

Metrology technologies are an essential adjunct to Integrated Circuit (I.C.) Semiconductor manufacturing. Scatterometry, an optical metrology, was chosen to measure 50 nm half pitch feature structures. A bread-board scatterometry system has been assembled to provide a non-contact, non-destructive, accurate and flexible measurement. A real-time, on-line scatterometry system has also been demonstrated and proven to provide a high throughput measurement.

Three different types of samples have been measured using the scatterometry setup. The wire-grid polarizer (WGP) sample has been made by Jet and Flash Nanoimprint Lithography with ~100 nm pitch and ~50 nm wide ~200 nm tall Al gratings on ...


Effects Of Position, Orientation, And Metal Loss On Ground Penetrating Radar Signals From Structural Rebar, David J. Eisenmann, Frank J. Margetan, Chien-Ping T. Chou, Shelby Ellis 2016 Iowa State University

Effects Of Position, Orientation, And Metal Loss On Ground Penetrating Radar Signals From Structural Rebar, David J. Eisenmann, Frank J. Margetan, Chien-Ping T. Chou, Shelby Ellis

David Eisenmann

Past experimental work on a highway bridge in central Iowa [1] suggested that ground penetrating radar (GPR) signals could possibly be used to differentiate intact rebar from those having substantial metal loss due to corrosion. That study made use of the amplitudes of GPR signals reflected by rebar, as obtained using a commercial instrument operated in pulse/echo mode. Many factors can contribute to the strength of the echo seen from a given rebar, including the rebar’s length, its distance from and tilt angle relative to the antenna, and the location and size of the metal-loss region. In this ...


Data Logging System For A Synthetic Aperture Radar Unit, Nicholas J. Testin, Philip Davis, Ian Dorell, Alexander Gillespie 2016 Kennesaw State University

Data Logging System For A Synthetic Aperture Radar Unit, Nicholas J. Testin, Philip Davis, Ian Dorell, Alexander Gillespie

Honors College Capstones and Theses

A small, existing radar unit lacked the ability to automatically store the data it was receiving, which made its use clunky and cumbersome. A system was constructed to allow an on-board microprocessor to track distance traveled, and automatically store the data output from the radar unit to a portable memory unit for later data processing. Distance traveled is determined using a specially designed mobile cart, which electronically converts the rotation of a wheel into an electrical signal while also providing stability for taking accurate radar measurements. The output data from the radar unit is stored as a properly-formatted sound file ...


Digital Commons powered by bepress