Electromagnetics and Photonics Commons^™

Characterizing Location-Based Electromagnetic Leakage Of Computing Devices Using Convolutional Neural Networks To Increase The Effectiveness Of Side-Channel Analysis Attacks, Ian C. Heffron

Theses and Dissertations

SCA attacks aim to recover some sort of secret information, often in the form of a cipher key, from a target device. Some of these attacks focus on either power-based leakage, or EM-based leakage. Neural networks have recently gained in popularity as tools in SCA attacks. Near-field EM probes with high-spatial resolution enable attackers to isolate physical locations above a processor. This enables attackers to exploit the spatial dependencies of algorithms running on said processor. These spatial dependencies result in different physical locations above a chip emanating different signal strengths. The strengths of different locations can be mapped using the …

Validation Of Bottom-Up Gnss Radio Occultation Method To Measure D- And E-Region Electron Density, Dylan J. Shaver

Theses and Dissertations

An in-depth validation of a new bottom-up approach using GNSS Radio Occultation (GNSS-RO) data to generate electron density profiles in the D- and E-region ionosphere. This comparison was completed using daytime ionosonde profiles when sporadic-E (E_s) was not present, and corresponding FIRI profiles. The average GNSS-RO profile is a few kilometers higher in altitude than the ionosonde profiles at the minimum frequency, f min. When the ionosonde profiles are shifted so that the altitudes match at f min, they are in good agreement up to the E-region peak altitude, hmE. Below f min, the …

The Electromagnetic Bayonet: Development Of A Scientific Computing Method For Aperture Antenna Optimization, Michael P. Ingold

Theses and Dissertations

The quiet zone of a radar range is the region over which a transmitted EM field approximates a uniform plane wave to within some finite error tolerance. Any target to be measured must physically fit within this quiet zone to prevent excess measurement error. Compact radar ranges offer significant operational advantages for performing RCS measurements but their quiet zone sizes are constrained by space limitations. In this work, a scientific computing approach is used to investigate whether equivalent-current transmitters can be designed that generate larger quiet zones than a conventional version at short range. A time-domain near-field solver, JefimenkoModels, was …

Magnetic Anomaly Mapping For Navigation, Luke T. Bergeron

Theses and Dissertations

Magnetic navigation (MagNav) has the potential to provide a global form of navigation that uses magnetic measurements of the Earth’s anomaly magnetic field and compares those measurements to a magnetic anomaly map in order to determine the user’s position. Widespread use of MagNav will require a database of fully-sampled, low-altitude magnetic anomaly maps. Existing magnetic anomaly map databases usually come from under- or poorly-sampled surveys. In this work, we provide an easy to follow MagNav anomaly map generation framework and set of survey collection metrics/requirements in an effort to help facilitate and standardize the creation of such a database. We …

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 …

Novel Photonic Structures And Materials, Samar Fawzy

Theses and Dissertations

Plasmonic materials provide the ability to confine light in metallic structures in the nanometre scale, enabling their use in a wide range of applications, including metamaterials, energy conversion, biomedical applications, and transformation optics. Conventional plasmonic materials such as Silver and Gold suffer from two problems: very large negative real permittivity (𝜀1), preventing their integration with low-permittivity dielectrics, and large losses associated with conduction electrons such as: electron-electron scattering, electron-phonon scattering or scattering by crystal defects. Therefore, the search for alternative structures and materials that overcome these obstacles is indeed an essential task. Metamaterials, three dimensional (3D) periodic subwavelength metallic/dielectric structures, …

High Power Microwave Operational Exposure Detection Using Thermoacoustic Wave Generation In Lossy Dielectric Polymers, James J. Frey

Theses and Dissertations

A feasibility analysis for the use of microwave-induced thermoacoustic (TA) wave generation in lossy dielectric media to detect pulsed high power microwave directed energy weapons in force health protection applications was conducted based on a series of empirical and computational investigations. A potential target volume material, carbon-loaded polytetrafluoroethylene, was identified for further study based on anticipated complex dielectric properties, with laboratory measurements of select electromagnetic (EM), thermal, and elastic material properties of relevance to the TA effect conducted to determine parameter values. A planar geometry TA-based signal chain model using thin film piezoelectric sensors was developed for both finite element …

Novel Compact Mimo Antenna Array Structures For 5g, Wi-Fi 6 And Vehicular Applications, Sulaiman Tariq

Theses and Dissertations

Due to the fast development of wireless communication applications, the study of Multiple Input Multiple Output (MIMO) communication systems has lately gained comprehensive research interests since it can significantly increase the channel capacity and link reliability without sacrificing bandwidth and/or power transmitted. However, the user equipment is constantly shrinking in size to support more applications and satisfy aesthetic needs, which increases the need for more compact, high-performance antenna array designs. Many techniques are being constantly developed to combat the effects of mutual coupling that arise with the miniaturization of MIMO arrays. This dissertation focuses on designing, testing, and evaluating new …

Analysis And Implementation Of Low Fidelity Radar-Based Remote Sensing For Unmanned Aircraft Systems, Matthew Duck

Theses and Dissertations

Radar-based remote sensing is consistently growing, and new technologies and subsequent techniques for characterization are changing the feasibility of understanding the environment. The emergence of easily accessible unmanned aircraft system (UAS) has broadened the scope of possibilities for efficiently surveying the world. The continued development of low-cost sensing systems has greatly increased the accessibility to characterize physical phenomena. In this thesis, we explore the viability and implementation of using UAS as a means of radar-based remote sensing for ground penetrating radar (GPR) and polarimetric scatterometry. Additionally, in this thesis, we investigate the capabilities and implementations of low-cost microwave technologies for …

Magnetic Flux Channel Antenna Design In Conformal Applications, William J. Tremblay

Theses and Dissertations

Magnetic Flux Channels (MFC) and Magneto-Dielectric Wire Antennas (MDWA) are effective, and in some cases, superior alternatives to traditional metallic antennas, in conformal and electrically small applications at the cost of fabrication and feed complexity. The frequency dispersive nature of magnetic material constituent parameters imposes constraints on the antenna design process, which were not fully developed in prior art. This research quantifies the key differences between the operating regions of magneto-dielectric materials for antenna applications and demonstrates the effectiveness of numerical method augmented modal analysis in the design process, regardless of operating region. Modeling challenges associated with MDWAs are addressed …

Magnetic Anomaly Absolute Positioning For Hypersonic Aircraft, Alexander J. Mcneil

Theses and Dissertations

GPS has proven to be an extremely valuable asset for navigation, and timing. GPS has become the standard navigation system for all applications, but GPS has limitations. GPS is susceptible to jamming, spoofing, and in the case of hypersonic aircraft, is likely unavailable. When an aircraft is traveling at hypersonic speeds, there is a plasma sheath that surrounds the aircraft. This plasma sheath blocks electromagnetic waves, and is therefore responsible for a GPS blackout. GPS unavailability for hypersonic aircraft has prompted the research into the viability of alternate navigation systems for these aircraft. This paper seeks to explore the viability …

Malware Detection Using Electromagnetic Side-Channel Analysis, Matthew A. Bergstedt

Theses and Dissertations

Many physical systems control or monitor important applications without the capacity to monitor for malware using on-device resources. Thus, it becomes valuable to explore malware detection methods for these systems utilizing external or off-device resources. This research investigates the viability of employing EM SCA to determine whether a performed operation is normal or malicious. A Raspberry Pi 3 was set up as a simulated motor controller with code paths for a normal or malicious operation. While the normal path only calculated the motor speed before updating the motor, the malicious path added a line of code to modify the calculated …

Low Insertion-Loss Nanophotonic Modulators Through Epsilon-Near-Zero Material-Based Plasmon-Assisted Approach For Integrated Photonics, Mohammad Ariful Hoque Sojib

Theses and Dissertations

Electro-optic/absorption Modulators (EOM/EAMs) encode high-frequency electrical signals into optical signals. With the requirement of large packing density, device miniaturization is possible by confining light in a sub-wavelength dimension by utilizing the plasmonic phenomenon. In plasmon, energy gets transferred from light to the form of oscillation of free electrons on a surface of a metal at an interface between the metal and a dielectric. Plasmonic provides increased light-matter interaction (LMI) and thus making the light more sensitive to local refractive index change. Plasmonic-based integrated nanophotonic modulators, despite their promising features, have one key limiting factor of large Insertion Loss (IL) which …

Characterization Of Anisotropic Materials Using Scattered Field Measurements, Hirsch M. Chizever

Theses and Dissertations

This research uses monostatic far-zone scattered field measurements to estimate the permittivity of biaxial materials at X-Band. Utilizing Radar Cross Section (RCS) measurement techniques, this effort examines the efficacy of whole-sample TEM illumination in the estimation of anisotropic permittivity, in contrast with traditional subsample illumination methods. The research examines the impact that dielectric supports have on measurement error and uncertainty in permittivity estimates. Following an incremental approach, the research first demonstrates successful estimation of permittivity for isotropic spheres followed by a Teflon isotropic cube. Finally, the method is applied to uniaxial and biaxial cubes whose anisotropic permittivity is validated through …

On-Chip Nanoscale Plasmonic Optical Modulators, Abdalrahman Mohamed Nader Abdelhamid

Theses and Dissertations

In this thesis work, techniques for downsizing Optical modulators to nanoscale for the purpose of utilization in on chip communication and sensing applications are explored. Nanoscale optical interconnects can solve the electronics speed limiting transmission lines, in addition to decrease the electronic chips heat dissipation. A major obstacle in the path of achieving this goal is to build optical modulators, which transforms data from the electrical form to the optical form, in a size comparable to the size of the electronics components, while also having low insertion loss, high extinction ratio and bandwidth. Also, lap-on-chip applications used for fast diagnostics, …

Cross-Junction Based Metasurfaces: A Roadmap To Fano Resonances, Mirna Soliman

Theses and Dissertations

The first part of the thesis presents a summary of the classification of materials, followed by the development of metamaterials and their salient role. Then, a study of metamaterials and the evolution of these 3D structures to 2D, known as metasurfaces, have been discussed. Moreover, the physics and practical interest behind Fano resonance have been discussed. Furthermore, the physical fundamentals guiding the performance of both the metamaterials and metasurfaces, including the temporal coupled-mode theory and the generalized laws of reflection and refraction, have been intensely investigated, along with some of the outstanding properties of the metamaterials. Then, a comparison between …

Modeling Aircraft Disturbance Fields For Magnetic Navigation Using Dense Anns And The Novel Manntl Architecture, Kyle A. Emery

Theses and Dissertations

The ability to use GPS for navigation is becoming increasingly limited in certain areas of the world. Knowing this, the Air Force Research Labs is constantly looking for ways to improve alternate navigation methods such as magnetic navigation. In the interest of making advancements in aircraft disturbance field modelling, Lieutenant Emery recreates models from previous works to prove results. Lieutenant Emery also introduces a novel model architecture that attempts to mix the filtering properties of Tolles-Lawson with the non-linear capabilities of an artificial neural network. The introduction of this model could present better aircraft disturbance field modelling and in turn, …

Studying The Conditions For Magnetic Reconnection In Solar Flares With And Without Precursor Flares, Seth H. Garland

Theses and Dissertations

Forecasting of solar flares remains a challenge due to the limited understanding of the triggering mechanisms associated with magnetic reconnection, the primary physical phenomenon connected to these events. Consequently, methods continue to rely on the climatology of solar flare events as opposed to the underlying physics principles. Models of magnetic reconnection in the solar atmosphere places the null point of the reconnection within the corona. Though as of now the coronal magnetic field cannot be directly measured, the field is tied to the photospheric magnetic field, which can be. This study utilized data from the Solar Dynamics Observatory Helioseismic and …

Real-Time Aerial Magnetic And Vision-Aided Navigation, Daniel J. Clarke

Theses and Dissertations

Aerial magnetic navigation has shown to be a viable alternative navigation method that has the potential for world-wide availability, to include over oceans. Obtaining GPS-level accuracy using magnetic navigation alone is challenging, but magnetic navigation can be combined with other alternative navigation methods that are more posed to obtaining GPS-level accuracy in their current state. This research presents an aerial navigation solution combining magnetic navigation and vision-aided navigation to aid an inertial navigation system (INS). The navigation solution was demonstrated in real-time playback using simulated magnetic field measurements and flight-test captured visual imagery. Additionally, the navigation solution was flight-tested on …

Computational Electromagnetic Modeling Of Metasurface Optical Devices With Defect Study, Carlos D. Diaz

Theses and Dissertations

One of the first fabricated metasurface optical devices, the in-plane V-antenna lenses, were plagued by a fundamental transmission limit (<25 >). Two distinct sets of Out-of-Plane phase elements were designed with improved transmission (~60 ). These were fabricated as beamsteerers and characterized in terms of their Bidirectional Transmittance Distribution Function measured as a function of scatter angle. Experimental data from the beamsteerers was analyzed via simulations using a finite element method (FEM). The measurements showed the designed beamsteering, but also a strong zero-order diffraction not present in the simulations, which motivated this study to understand what was causing these differences. …

Linear And Nonlinear Optical Effects In High Carrier Concentration Oxides And Nitrides At Epsilon-Near-Zero, Ray Secondo

Theses and Dissertations

Nonlinear optics has been an important method for achieving ultrafast light manipulation. Recently, ENZ material have gained interest due to inherent advantages such as slow light, improved confinement, and ideal relaxation times, the nonlinear response of these materials, such as the intensity-dependent-refractive-index, are ultra-large yet remain ultra-fast. This experimental discovery of epsilon-near-zero enhancement has thus opened new avenues in nonlinear optics research in recent years, and while experiments have continued to progress a theoretical understanding of the processes and origins of nonlinear optical enhancement at epsilon-near-zero has lagged.

To fill this gap, the work herein focuses on uncovering the mechanisms …

Sparse Bases And Bayesian Inference Of Electromagnetic Scattering, John Lee

Theses and Dissertations

Many approaches in CEM rely on the decomposition of complex radiation and scattering behavior with a set of basis vectors. Accurate estimation of the quantities of interest can be synthesized through a weighted sum of these vectors. In addition to basis decompositions, sparse signal processing techniques developed in the CS community can be leveraged when only a small subset of the basis vectors are required to sufficiently represent the quantity of interest. We investigate several concepts in which novel bases are applied to common electromagnetic problems and leverage the sparsity property to improve performance and/or reduce computational burden. The first …

Electromagnetic Interference Estimation Via Conditional Neural Processing, Edgar E. Gomez

Theses and Dissertations

The goal of this thesis is to determine the efficacy of employing Machine Learning (ML) to solve Joint Urgent Operational Need (JUON) CC-0575, which aims to develop a Common Operating Picture (COP) of the Global Positioning System (GPS) Electromagnetic Interference (EMI) environment. With the growing popularity of Artificial Neural Networks (ANNs), ML solutions are quickly gaining traction in businesses, academia and government. This in turn allows for problem solutions that were previously inconceivable using the classical programming paradigm. This thesis proposes a method to develop a COP of the battlefield via ANN ingestion of multiple-source signals and sensors. We conduct …

Dynamic Micromechanical Fabry-Perot Cavity Sensors Fabricated By Multiphoton Absorption Onto Optical Fiber Tips, Jeremiah C. Williams

Theses and Dissertations

This research leveraged two-photon polymerization microfabrication to integrate dynamic mechanical components with Fabry-Perot resonators onto the ends of low-loss optical fibers to prototype 3 micro-optic devices. The first device featured a multi-positional mirror that enabled thin-film deposition onto cavities of any length with mirrors of significant curvature, for refractive index sensing. The second device combined an FP cavity with a spring body featuring easily scalable stiffness for pressure sensing. The third device presented a high-speed rotating micro-anemometer for measuring a wide range of gas flows. All devices represent a significant reduction in size and weight over commercially available devices.

Characterization And Sensitivity Analysis Of 6 Meter Cassegrain Antenna, James L. Harris

Theses and Dissertations

This paper will characterize a 6 meter in diameter cassegrain antenna. The cassegrain antenna is a special form of a dual reflector antenna which uses a main reflector following a parabolic curve and a sub reflector which follows a hyperbolic curve. Cassegrain style antennas have multiple parameters which can be tuned to achieve specific design goals. Performing a sensitivity analysis will establish relationships between design parameters, directivity, side lobe levels, and effects of strut geometry. The initial design parameters will be assumed based on typical values. Results from the sensitivity analysis will be used to provide a performance band for …

Focused Beam System Biaxial Material Characterization, Nicholas A. O'Gorman

Theses and Dissertations

Electromagnetic material characterization is the process of determining the constitutive parameters (complex permittivity and permeability) of given a sample. Due to the large number of unknowns involved, multiple unique measurements are required for material property extraction. Many measurement methods, such as waveguides and striplines, possess a rigid internal structure that the sample being measured must adhere to. This rigidity limits these methods to samples that fit within the device and inhibits oblique sample orientations, limiting the number of independent measurements that can be obtained. A focus beam system, due to being an open system with greater freedom in sample size …

Improving Aeromagnetic Calibration Using Artificial Neural Networks, Mitchell C. Hezel

Theses and Dissertations

The Global Positioning System (GPS) has proven itself to be the single most accurate positioning system available, and no navigation suite is found without a GPS receiver. Even basic GPS receivers found in most smartphones can easily provide high quality positioning information at any time. Even with its superb performance, GPS is prone to jamming and spoofing, and many platforms requiring accurate positioning information are in dire need of other navigation solutions to compensate in the event of an outage, be the cause hostile or natural. Indeed, there has been a large push to achieve an alternative navigation capability which …

Measurement Of The 160Gd(P,N)160Tb Excitation Function From 4 18 Mev, Using A Stacked Foil Technique, Ryan K. Chapman

Theses and Dissertations

A stack of thin Gd, Ti, and Cu foils were irradiated with an 18 MeV proton beam at Lawrence-Berkeley National Laboratory's 88-Inch Cyclotron to investigate the ¹⁶⁰Gd(p,n)¹⁶⁰Tb nuclear reaction for nuclear forensics applications. This experiment will improve knowledge of ¹⁶⁰Tb production rates, allowing ¹⁶⁰Tb to be efficiently created in a foil stack consisting of other proton induced isotopes for forensics applications. A set of 15 measured cross sections between 4-18 MeV for ¹⁶⁰Gd(p,n)¹⁶⁰Tb were obtained using a stacked foil technique. The foil stack consisted of one stainless steel, one iron, fifteen gadolinium, …

Neutron Displacement Damage In Germanium Tin Photodiodes, Nathan J. Gale

Theses and Dissertations

GeSn is a promising material for photodiodes in the near-to-mid infrared (IR) spectrum because of new growth methods that enable integration with complementary metal oxide semiconductor (CMOS) technology. While natural germanium has a threshold wavelength of 1800 nm, 6.9 Sn content extends the threshold wavelength to 2700 nm based on a Sn content dependent bandgap. Also, unlike other semiconductors that require liquid nitrogen cooling to act as an IR sensor, GeSn can be operated at room temperature, enabling a wide variety of applications. In this study, photodiodes ranging from 0 to 6.9 tin content were subjected to 1 MeV (Si) …

Detection Of Reconnection Signatures In Solar Flares, Taylor R. Whitney

Theses and Dissertations

Solar flare forecasting is limited by the current understanding of mechanisms that govern magnetic reconnection, the main physical phenomenon associated with these events. As a result, forecasting relies mainly on climatological correlations to historical events rather than the underlying physics principles. Solar physics models place the neutral point of the reconnection event in the solar corona. Correspondingly, studies of photospheric magnetic fields indicate changes during solar flares -- particularly in relation to the field helicity -- on the solar surface as a result of the associated magnetic reconnection. This study utilizes data from the Solar Dynamics Observatory (SDO) Helioseismic and …