Electromagnetics and Photonics Commons^™

Analysis Of Dual-Element Antenna Configurations, Grant J. Evans

College of Graduate Studies: Theses & Dissertations

Dual-dipole antennas have been extensively researched previously for their bandwidth enhancing effect on Yagi type antennas. In this thesis, dual-dipole antennas are fabricated and measured. These experimental measurement results are verified with simulated values. First, a standard dual-dipole antenna is investigated and found that the high magnitude, opposite current directions on the dipole arms are the reasoning behind the creation of a high gain mode. This pattern is similar to a Yagi antenna. Next, a dual-band implementation of the dual-dipole antenna is shown, with two distinct resonances in a lower band and an upper band. Both bandwidths exhibit a dipole …

Methods On Implementing Radar And Antenna Solutions To Defense And Biomedical Problems, Jalexis E. Vanga Guzman

College of Graduate Studies: Theses & Dissertations

Growing developments in antenna and radio frequency systems have created a strong incentive for researchers to study and apply electromagnetic (EM)-based solutions to modern defense and biomedical problems. The ability to transmit and receive EM waves using antenna systems has not only increased global connectivity, but also increased the need for innovation in antenna size reduction and development of radar systems.

Size reduction techniques have been extensively studied for antennas after the development of electrically small antennas (ESAs) which follow Chu’s limit. ESAs allow the implementation of antennas with much smaller foot-size than traditional full-sized designed while keeping the same …

Methodology For Analyzing Coupling Mechanisms In Rfi Problems Based On Peec, Xu Wang, Anfeng Huang, Wei Zhang, Reza Yazdani, Donghyun Kim, Takashi Enomoto, Taketoshi Sekine, Kenji Araki, Jun Fan, Chulsoon Hwang

Electrical and Computer Engineering Faculty Research & Creative Works

In This Article, a Method for Analyzing Coupling Mechanisms in Radio Frequency Interference (RFI) Problems is Proposed. the Partial Element Equivalent Circuit (PEEC) Method is First Used to Derive the Retarded Inductances and Capacitances between Different Mesh Cells. with the Introduction of a Novel Partitioning Algorithm, the Capacitive Coupling and Inductive Coupling between Arbitrary Layout Parts Can Be Quantified based on the Magnitude of the Displacement Current and Induced Voltage Drop. the Accuracy of the PEEC Models is Validated by Comparison with Different Commercial Tools. the Proposed Coupling Mechanism Analysis Flow Provides a Useful Prelayout Tool for RFI Risk Analysis.

Electromagnetic Transmit Array With Optical Control For Beamforming, Wei Zhang, Javad Meiguni, Yin Sun, Muqi Ouyang, Xin Yan, Xu Wang, Reza Yazdani, Daryl G. Beetner, Donghyun Kim, David Pommerenke

Electrical and Computer Engineering Faculty Research & Creative Works

This Proof-Of-Concept Paper Demonstrates the Feasibility of using a Slide Projector to Steer the Beam of a Transmit Array by Adding Solar Cells and Varactor Diodes to Each Unit Cell. by Irradiating Each Solar Cell with the Light of Different Intensities from a Slide Projector, the Measured Phase of the Wave Transmitted by the 4x4 Transmit Array Shifts within 92° at 4.26 GHz, While the Variation in Magnitude is Measured within 4 DB. Different Light Configurations Are Identified Via a Searching Algorithm to Achieve Peak/null Beamforming in a Particular Direction. the Beam of the Prototypical 4x4 Transmit Array Can Be …

The Effect Of The Width Of The Incident Pulse To The Dielectric Transition Layer In The Scattering Of An Electromagnetic Pulse — A Qubit Lattice Algorithm Simulation, George Vahala, Linda Vahala, Abhay K. Ram, Min Soe

Electrical & Computer Engineering Faculty Publications

The effect of the thickness of the dielectric boundary layer that connects a material of refractive index n₁ to another of index n₂is considered for the propagation of an electromagnetic pulse. A qubit lattice algorithm (QLA), which consists of a specially chosen non-commuting sequence of collision and streaming operators acting on a basis set of qubits, is theoretically determined that recovers the Maxwell equations to second-order in a small parameter ϵ. For very thin boundary layer the scattering properties of the pulse mimics that found from the Fresnel jump conditions for a plane wave - except that …

Microstrip Antenna Design Using Cst Optimized By Neural Network Algorithm, Hadeer. A Shoeab, Mohamed A.Mohamed, Marzouk El Said A, Ahmed. A. Kabeel

Mansoura Engineering Journal

In this paper, a general design procedure is suggested for the microstrip antennas using artificial neural networks and this is demonstrated using the rectangular patch geometry. The model was analyzed for 1733 data sets of input output parameters. 1300 samples for training and 433 samples for testing and 1500 epoch, learning rate from (0.003 to 0.005). Python was used to create and implement the ANN algorithm model. The mean error in detection of resonance frequencies (return loss peaks) was 0.144GHz on train set, and 0.116GHz on test set. The outputs of the radial basis function are optimized by varying the …

Carrier Transport Engineering In Wide Bandgap Semiconductors For Photonic And Memory Device Applications, Ravi Teja Velpula

Dissertations

Wide bandgap (WBG) semiconductors play a crucial role in the current solid-state lighting technology. The AlGaN compound semiconductor is widely used for ultraviolet (UV) light-emitting diodes (LEDs), however, the efficiency of these LEDs is largely in a single-digit percentage range due to several factors. Until recently, AlInN alloy has been relatively unexplored, though it holds potential for light-emitters operating in the visible and UV regions. In this dissertation, the first axial AlInN core-shell nanowire UV LEDs operating in the UV-A and UV-B regions with an internal quantum efficiency (IQE) of 52% are demonstrated. Moreover, the light extraction efficiency of this …

Emergence Of Coherent Backscattering From Sparse And Finite Disordered Media, Nooshin M. Estakhri, Nasim Mohammadi Estrakhri, Theodore B. Norris

Engineering Faculty Articles and Research

Coherent backscattering (CBS) arises from complex interactions of a coherent beam with randomly positioned particles, which has been typically studied in media with large numbers of scatterers and high opacity. We develop a first-principles scattering model for scalar waves to study the CBS cone formation in finite-sized and sparse random media with specific geometries. The current study provides insights into the effects of density, volume size, and other relevant parameters on the angular characteristics of the CBS cone emerging from sparse and bounded random media for various types of illumination, with results consistent with well-known CBS studies which are typically …

Orbital Angular Momentum Orthogonality-Based Crosstalk Reduction: Theory And Experiment, Unaiza Tariq

Electrical Engineering Theses and Dissertations

Full duplex communication systems allow a single channel to be used for simultaneous two-way communication, increasing spectral efficiency. However, full duplex communication systems suffer from the issue of self-interference between local transmitter and receiver antennas. Analog subtraction and signal processing methods have previously been used to reduce this problem. This dissertation proposes the use of waves carrying orbital angular momentum (OAM) to mitigate the problem of self-interference by offering a means of additional isolation between local antennas.

Orbital angular momentum has been widely studied both in the photonics and radio domain. The theoretically infinite orthogonal states of an OAM signal …

Development And Application Of A Design Flow For Photonic Integrated Circuits, Ifeanyi Achu

Electrical Engineering Theses and Dissertations

Silicon photonics allows for the fabrication of many optical elements on a single photonic integrated circuit (PIC). By taking advantage of the established foundry technology used in the CMOS and silicon’s high refractive index, high feature density manufacturing can be achieved in mass quantities. In CMOS fabrication, from conception of an electronic circuit to testing, the process of designing an electronic circuit is dictated by a design flow which has been developed over the course of decades. This flow includes circuit level design and simulation, layout of the circuit, layout and verification of the chip, fabrication, packaging, and testing. Given …

Void-Semiconductor Gaas Photonic Crystal Surface-Emitting Lasers By Epitaxial Regrowth And Single-Epitaxy Methods, Kevin James Reilly

Nanoscience and Microsystems ETDs

Monolithic semiconductor lasers including edge-emitting lasers (EELs) and vertical-cavity surface-emitting lasers (VCSELs) fail to realize simultaneous achievement of both high-power high-quality beams due to intrinsic limitations of their resonant cavity. Photonic crystal surface emitting lasers (PCSELs) address these structural limitations through employment of a two-dimensional photonic crystal (PC) cavity that creates feedback at a single wavelength for laterally scalable devices. This function of the PC allows PCSELs to power scale with area while maintaining single-mode emission required for diffraction-limited beams. In this way, PCSELs fulfill an industry demand for high-power high-quality lasing from a single chip.

Early PCSELs were fabricated …

Six-Dimensional Single-Molecule Imaging With Isotropic Resolution Using A Multi-View Reflector Microscope, Oumeng Zhang, Zijian Guo, Yuanyuan He, Tingting Wu, Michael D. Vahey, Matthew D. Lew

Electrical & Systems Engineering Publications and Presentations

Imaging of both the positions and orientations of single fluorophores, termed single-molecule orientation-localization microscopy, is a powerful tool for the study of biochemical processes. However, the limited photon budget associated with single-molecule fluorescence makes high-dimensional imaging with isotropic, nanoscale spatial resolution a formidable challenge. Here we realize a radially and azimuthally polarized multi-view reflector (raMVR) microscope for the imaging of the three-dimensional (3D) positions and 3D orientations of single molecules, with precisions of 10.9 nm and 2.0° over a 1.5-μm depth range. The raMVR microscope achieves 6D super-resolution imaging of Nile red molecules transiently bound to lipid-coated spheres, accurately resolving …

Optical Control System For Atmospheric Turbulence Mitigation, Martyn Lemon

All Theses

Propagation of laser light is distorted in the presence of atmospheric turbulence. This poses an issue for sensing, free-space optical communications, and transmission of power. With an ever-increasing demand for high-speed data communications, particularly between satellites, unmanned vehicles, and other systems that benefit from a point-to-point link, this issue is critical for the field. A variety of methods have been proposed to circumvent this issue. Some major categories include the manipulation of the light’s structure, an adaptive scheme at the optical receiver, scanning mirror systems, or a transmission of simultaneous signals with a goal to improve robustness.

There is an …

Oam-Based Wavelets In A High Speed Optical Probing System For Measuring The Angular Decomposition Of The Environment, Justin Free

All Theses

This thesis presents the theoretical development of orbital angular momentum (OAM) based wavelets for the analysis of localized OAM information in space. An optical probing system for generating and detecting these wavelets is demonstrated; individual wavelets can scan the environment in 10µs or less. The probing system was applied to a three-dimensional atmospheric turbulence distribution to obtain a continuous wavelet transform of the angular information of the turbulent propagation path about a fixed radius. An entire continuous wavelet transform was measured in 3.8ms; the measurements are much faster than the turbulence and give insight into the short time scale of …

Data-Driven Deep Learning-Based Analysis On Thz Imaging, Haoyan Liu

Graduate Theses and Dissertations

Breast cancer affects about 12.5% of women population in the United States. Surgical operations are often needed post diagnosis. Breast conserving surgery can help remove malignant tumors while maximizing the remaining healthy tissues. Due to lacking effective real-time tumor analysis tools and a unified operation standard, re-excision rate could be higher than 30% among breast conserving surgery patients. This results in significant physical, physiological, and financial burdens to those patients. This work designs deep learning-based segmentation algorithms that detect tissue type in excised tissues using pulsed THz technology. This work evaluates the algorithms for tissue type classification task among freshly …

Processes & Toolchain For Automation Of Hybrid Direct-Write 3d Printing, Gilbert Thomas Carranza

Open Access Theses & Dissertations

Hybrid 3D printing has evolved from a means to rapidly prototype devices to a fully viable means of manufacturing final products. In particular, electronic and electromagnetic devices have been a focus of hybrid 3D printing multi material structures. However, while the hardware capabilities have been around for years, the software capabilities have only begun to catch up. A process and toolchain for hybrid 3D printing is critically needed.This work details a process and toolchain for hybrid 3D printing metal dielectric structures. In it, a basic slicing algorithm is shown along with off-axis printing and conformal printing for arbitrary curvatures. These …

Pioneering Concepts For 3d Electromagnetics, Cesar Valle

Open Access Theses & Dissertations

This work introduces two paradigm changing concepts that will push electromagnetics (EM) to the third dimension. The first of that work involves the introduction of the conformal Spatially Variant Lattice (SVL) algorithm that can conform any periodic structure onto arbitrary curvature. The algorithms robustness is confirmed by conforming a frequency selective surface (FSS) onto an extreme paraboloid, proving the algorithms robustness on high sloping surfaces. Three FSSs were made in total; a standard flat FSS, a projected FSS, and a FSS made through the conformal SVL algorithm. Measured results are shown and match well to simulation.Secondly, in the world of …

Reliability Enhancing Control Algorithms For Two-Stage Grid-Tied Inverters, Yuheng Wu

Graduate Theses and Dissertations

In the photovoltaic (PV) generation system, two types of grid-tied inverter systems are usually deployed: the single-stage grid-tied inverter system and the two-stage grid-tied inverter system. In the single-stage grid-tied inverter system, the input of the inverter is directly connected to the PV arrays, while an additional dc-dc stage is inserted between the PV arrays and the dc-ac inverter in the two-stage design. The additional dc-dc stage could provide a stable dc-link voltage to the inverter, which also enables new design possibilities, including the multi-MPPT operation and solar-plus-storage application. Thus, the two-stage grid-tied inverter has been widely used in the …

Effects Of A Non-Uniform Magnetic Field On The Current Flow Of Silicon Photodiodes And Solar Cells, Jason J. Buranich

Theses and Dissertations

This research investigates an approach to improve efficiency of low-cost devices by applying an external arched magnetic field to p-n junction devices to observe the effect such a magnetic field would have on the flow of charge carriers. Electro-optic p-n junction devices of photodiodes and solar cells were designed and fabricated to incorporate the dimensions of commercially available neodymium magnets. The devices were placed in the magnetic fields created by the magnets then current and voltage characteristics were measured via a 4-point probe setup. These measurements were compared to measurements taken from the same devices when not in the magnetics …

A Patient-Specific Algorithm For Lung Segmentation In Chest Radiographs, Manawaduge Supun De Silva, Barath Narayanan Narayanan, Russell C. Hardie

Electrical and Computer Engineering Faculty Publications

Lung segmentation plays an important role in computer-aided detection and diagnosis using chest radiographs (CRs). Currently, the U-Net and DeepLabv3+ convolutional neural network architectures are widely used to perform CR lung segmentation. To boost performance, ensemble methods are often used, whereby probability map outputs from several networks operating on the same input image are averaged. However, not all networks perform adequately for any specific patient image, even if the average network performance is good. To address this, we present a novel multi-network ensemble method that employs a selector network. The selector network evaluates the segmentation outputs from several networks; on …