Singh Center for Nanotechnology
Dartmouth College
California Polytechnic State University, San Luis Obispo
Georgia Southern University
University of Arkansas, Fayetteville
Missouri University of Science and Technology
University of Massachusetts Amherst
Emergence Of Coherent Backscattering From Sparse And Finite Disordered Media,
2022
Chapman University
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 …
A Low Profile Microstrip Patch Antenna Using A Polygon-Shaped Patch For Wireless Applications.,
2022
B.S.Abdur Rahman Crescent Institute of Science and Technology
A Low Profile Microstrip Patch Antenna Using A Polygon-Shaped Patch For Wireless Applications., Muthu Krishnan Ramar, Kannan G
International Journal of Electronics Signals and Systems
In this paper. a low profile microstrip patch antenna is presented. The FR4 substrate is chosen for the dielectric substrate with a height of 1.6 mm. The presented antenna employs a polygon-shaped patch as the radiator for operating at 2.4 GHz. Co-axial feed is selected to excite the resented antenna to retain the low profile property of the antenna. The simulated results of the proposed antenna were analyzed and the structure of the proposed antenna was validated through fabrication results. The vector network analyzer is used to measure the real-time return loss property of the presented antenna.
High Power Microwave Operational Exposure Detection Using Thermoacoustic Wave Generation In Lossy Dielectric Polymers,
2022
Air Force Institute of Technology
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 …
Golightly : A Gpu Implementation Of The Finite-Difference Time-Domain Method,
2022
Southern Methodist University
Golightly : A Gpu Implementation Of The Finite-Difference Time-Domain Method, S. David Lively
Electrical Engineering Theses and Dissertations
Traditionally, optical circuit design is tested and validated using software which implement numerical modeling techniques such as Beam Propagation, Finite Element Analysis and the Finite-Difference Time-Domain (FDTD) method. FDTD simulations require significant computational power. Existing installations may distribute the computational requirements across large clusters of high-powered servers. This approach entails significant expense in terms of hardware, staffing and software support which may be prohibitive for some research facilities and private-sector engineering firms. The application of modern programmable GPUs to problems in scientific visualization and computation has facilitated faster development cycles for a variety of industry segments including large dataset visualization, …
Algorithms For Exploration Of Advanced Electromagnetic Concepts,
2022
University of Texas at El Paso
Algorithms For Exploration Of Advanced Electromagnetic Concepts, Asad Ullah Hil Gulib
Open Access Theses & Dissertations
3D printing is revolutionizing the manufacturing industry and is now being considered in the electronics industry. The creation of the worldâ??s first 3D volumetric circuit has made a way to make circuits smaller, lighter, into unconventional form factors and exploit physics like anisotropy more effectively than planar geometries can. While this is exciting, many problems must be solved to make 3D volumetric circuits more efficient. One of these problems is electromagnetic interference and mutual coupling between the circuit components that are expected to increase in high-frequency 3D circuits. Spatially variant anisotropic metamaterials (SVAMs) could be a solution to overcome this …
Digital And Gradient Refractive Index Planar Optics By Nanoimprinting Porous Silicon,
2022
Clemson University
Digital And Gradient Refractive Index Planar Optics By Nanoimprinting Porous Silicon, Anna Hardison
All Theses
Due to the drawbacks of traditional refractive optics, the implementation of planar or nearly planar optical devices has been of research interest for over a century. Subwavelength gratings are a particularly promising option for creating flat optical devices; however, the implementation of subwavelength grating-based optics is limited by fabrication constraints. Recently, we implemented flat optical devices using the nanoimprinting of refractive index (NIRI) process, a process which was pioneered in a previous study but remained largely unproven in terms of device fabrication. The planar, gradient index microlenses we fabricated were found to possess an effective medium similar to a subwavelength …
Remote Human Vital Sign Monitoring Using Multiple-Input Multiple-Output Radar At Millimeter-Wave Frequencies,
2022
University of Tennessee, Knoxville
Remote Human Vital Sign Monitoring Using Multiple-Input Multiple-Output Radar At Millimeter-Wave Frequencies, Toan Khanh Vo Dai
Doctoral Dissertations
Non-contact respiration rate (RR) and heart rate (HR) monitoring using millimeter-wave (mmWave) radars has gained lots of attention for medical, civilian, and military applications. These mmWave radars are small, light, and portable which can be deployed to various places. To increase the accuracy of RR and HR detection, distributed multi-input multi-output (MIMO) radar can be used to acquire non-redundant information of vital sign signals from different perspectives because each MIMO channel has different fields of view with respect to the subject under test (SUT). This dissertation investigates the use of a Frequency Modulated Continuous Wave (FMCW) radar operating at 77-81 …
Fabrication Of Nb3Sn By Magnetron Sputtering For Superconducting Radiofrequency Application,
2022
Old Dominion University
Fabrication Of Nb3Sn By Magnetron Sputtering For Superconducting Radiofrequency Application, Md Nizam Sayeed
Electrical & Computer Engineering Theses & Dissertations
Particle accelerators are considered as an important device that has wide applications in cancer treatment, sterilizing waste, preserving foods, ion implantation in semiconductor industry, and in production of isotopes for medical applications. Superconducting radiofrequency (SRF) cavities are the building blocks of a linear particle accelerator. Current particle accelerators use niobium (Nb) superconductors as the sheet material to fabricate a single SRF cavity for particle acceleration. With better superconducting properties (critical temperature Tc ~ 18.3 K, superheating field Hsh~ 400 mT), Nb3Sn is considered a potential candidate in SRF technology. Magnetron sputtering is a promising deposition …
Design And Operation Of A Microwave Flow Cytometer For Single Cell Detection And Identification,
2022
Clemson University
Design And Operation Of A Microwave Flow Cytometer For Single Cell Detection And Identification, Jeffrey A. Osterberg
All Dissertations
Microwave dielectric sensing has become a popular technique in biological cell sensing for its potential in online, label-free, and real-time sensing. At microwave frequencies probing signals are sensitive to intracellular properties since they are able to penetrate cell membranes, making microwave flow cytometry a promising technology for label-free biosensing. In this dissertation a microwave flow cytometer is designed and used to measure single biological cells and micro particles. A radio frequency (RF)/microwave interferometer serves as the measurement system for its high sensitivity and tunability and we show that a two-stage interferometer can achieve up to 20 times higher sensitivity than …
Subwavelength Engineering Of Silicon Photonic Waveguides,
2022
Clemson University
Subwavelength Engineering Of Silicon Photonic Waveguides, Farhan Bin Tarik
All Dissertations
The dissertation demonstrates subwavelength engineering of silicon photonic waveguides in the form of two different structures or avenues: (i) a novel ultra-low mode area v-groove waveguide to enhance light-matter interaction; and (ii) a nanoscale sidewall crystalline grating performed as physical unclonable function to achieve hardware and information security. With the advancement of modern technology and modern supply chain throughout the globe, silicon photonics is set to lead the global semiconductor foundries, thanks to its abundance in nature and a mature and well-established industry. Since, the silicon waveguide is the heart of silicon photonics, it can be considered as the core …
Materials Design For Energy Applications Using Ab- Initio Calculations,
2022
University of Arkansas, Fayetteville
Materials Design For Energy Applications Using Ab- Initio Calculations, Hind Hemaidee Alqurashi
Graduate Theses and Dissertations
The structural, dynamical, electronic, and thermoelectric properties of rock-salt and wurtzite Cd1-xZnxO alloys, VTiRhZ (Al, Ga, In, Si, Ge, Sn) and ZrTiRhZ (Ge, Sn) quaternary Heusler alloys (QHAs) were investigated using density functional theory (DFT) and semi-classical Boltzmann transport theory. From these calculations, the alloys were identified as potential materials for future thermoelectric applications. Furthermore, the magnetic and spin-polarization properties of these QHAs were investigated. The total magnetic moments were found to be integer values for all QHAs. In addition, all studied QHAs except VTiRhAl possess a half-metallic behavior with a 100% spin-polarization. The half-metallic ferromagnetic behavior makes them promising …
Arrayed Waveguide Lens For Beam Steering,
2022
CUNY Queens College
Arrayed Waveguide Lens For Beam Steering, Mostafa Honari-Latifpour, Ali Binaie, Mohammad Amin Eftekhar, Nicholas Madamopoulos, Mohammad-Ali Miri
Publications and Research
Integrated planar lenses are critical components for analog optical information processing that enable a wide range of applications including beam steering. Conventional planar lenses require gradient index control which makes their on-chip realization challenging. Here, we introduce a new approach for beam steering by designing an array of coupled waveguides with segmented tails that allow for simultaneously achieving planar lensing and off-chip radiation. The proposed arrayed waveguide lens is built on engineering the evanescent coupling between adjacent channels to realize a photonic lattice with an equi-distant ladder of propagation constants that emulates the continuous parabolic index profile. Through coupled-mode analysis …
Nonreciprocal Surface Waves On Gyrotropic Interfaces,
2022
University of Wisconsin-Milwaukee
Nonreciprocal Surface Waves On Gyrotropic Interfaces, Alexander Martin Holmes
Theses and Dissertations
In this dissertation, the properties of highly nonreciprocal (unidirectional) surface waves guided along the interface between free-space and various 2D and 3D gyrotropic continua are investigated using analytic, numerical, and experimental methods. From a classical electromagnetics perspective, nonreciprocity in the dispersion of surface wave modes supported by the interface is achieved by breaking both time-reversal and space-inversion symmetries in the collective response of the waveguide, which consists of the two interfaced materials. More recently, however, a connection to momentum space topology via the bulk-edge correspondence principle has been made for gyrotropic continua, providing additional insights into the underlying physics that …
Study Of Single-Photon Wave-Packets With Atomically Thin Nonlinear Mirrors,
2022
University of Arkansas, Fayetteville
Study Of Single-Photon Wave-Packets With Atomically Thin Nonlinear Mirrors, Christopher Klenke
Graduate Theses and Dissertations
A novel controlled phase gate for photonic quantum computing is proposed by exploiting the powerful nonlinear optical responses of atomically thin transition metal dichalcogenides (TMDs) and it is shown that such a gate could elicit a π-rad phase shift in the outgoing electric field only in the case of two incident photons and no other cases. Firstly, the motivation for such a gate is developed and then the implementation of monolayer TMDs is presented as a solution to previous realization challenges. The single-mode case of incident photons upon a TMD is derived and is then used to constrain the more …
Development Of Medium Power High Efficiency Multi-Level Buck-Boost Dc-Dc Converter,
2022
School of Electronics and Communication Engineering, Shri Mata Vaishno Devi University, Katra 182320, Jammu and Kashmir, India
Development Of Medium Power High Efficiency Multi-Level Buck-Boost Dc-Dc Converter, Yogesh Singh, Sunny Sharma, Sandeep Tuli
International Journal of Electronics Signals and Systems
Power DC/DC converters or regulators form the backbone of different portable electronic devices like cellular phones, laptops, portable electronic devices which are using batteries as their power supply. Portable devices usually comprise of several sub-circuits that should be supplied with different voltage levels, which are not the same as battery’s voltage level which is the main supply voltage. A new approach of buck-boost converter is presented in this paper, that automatically detects the zero-inductor current & compels the convertor to deliberately switch from Continuous Conduction Mode (CCM) to Discontinuous Conduction Mode (DCM), once the inductor current attempts towards negative values, …
A Study On Electromagnetic Topology Optimization Using Binary Particle Swarm Algorithm,
2022
University of New Mexico
A Study On Electromagnetic Topology Optimization Using Binary Particle Swarm Algorithm, Mohammad Sazzad Hossain
Electrical and Computer Engineering ETDs
Topology optimization is a state-of-the-art tool for detecting the best material layout in a physical space to obtain certain goals. Initially developed as a structural engineering tool, it has been recently used in electromagnetics and has shown immense potential. The aim of this work is to build a framework for applying the topology optimization method in electromagnetics using a modified binary particle swarm optimization (BPSO) algorithm. In this thesis, a very classic problem of coax to waveguide transition has been considered, and a novel solution has been given using topology optimization. The steps to implementing topology optimization using BPSO have …
Nystrom Methods For High-Order Cq Solutions Of The Wave Equation In Two Dimensions,
2022
New Jersey Institute of Technology
Nystrom Methods For High-Order Cq Solutions Of The Wave Equation In Two Dimensions, Erli Wind-Andersen
Dissertations
An investigation of high order Convolution Quadratures (CQ) methods for the solution of the wave equation in unbounded domains in two dimensions is presented. These rely on Nystrom discretizations for the solution of the ensemble of associated Laplace domain modified Helmholtz problems. Two classes of CQ discretizations are considered: one based on linear multistep methods and the other based on Runge-Kutta methods. Both are used in conjunction with Nystrom discretizations based on Alpert and QBX quadratures of Boundary Integral Equation (BIE) formulations of the Laplace domain Helmholtz problems with complex wavenumbers. CQ in conjunction with BIE is an excellent candidate …
Sub-Nyquist Optical Pulse Sampling For Photonic Blind Source Separation,
2022
Rowan University
Sub-Nyquist Optical Pulse Sampling For Photonic Blind Source Separation, Taichu Shi, Yang Qi, Weipeng Zhang, Paul Prucnal, Jie Li, Ben Wu
Henry M. Rowan College of Engineering Faculty Scholarship
We propose and experimentally demonstrate an optical pulse sampling method for photonic blind source separation. The photonic system processes and separates wideband signals based on the statistical information of the mixed signals, and thus the sampling frequency can be orders of magnitude lower than the bandwidth of the signals. The ultra-fast optical pulses collect samples of the signals at very low sampling rates, and each sample is short enough to maintain the statistical properties of the signals. The low sampling frequency reduces the workloads of the analog to digital conversion and digital signal processing systems. In the meantime, the short …
Design Of An Offner-Chrisp Imaging Spectrometer For A Planetary Fluorescence Instrument,
2022
Washington University in St. Louis
Design Of An Offner-Chrisp Imaging Spectrometer For A Planetary Fluorescence Instrument, Tristan Wells Carlson
McKelvey School of Engineering Theses & Dissertations
Spectrometers have been an integral part of space exploration in the late 20th and 21st centuries and will continue to provide quantitative measurements to answer exciting questions like, “Is or was there life on other planets?” PERISCOPE, Probe for Exploring Regolith and Ice by Subsurface Classification of Organics, Polycyclic aromatic hydrocarbons, and Elements, is a next generation spectrometer designed to explore icy worlds like Europa. It uses time-resolved ultraviolet (UV) fluorescence spectroscopy, a technique that identifies organic molecules, polycyclic aromatic hydrocarbons (PAH), and rare earth elements (REE). Photon wavelength discrimination is very important for this technique and is accomplished by …
Mutual Coupling Reduction Techniques For Multi-Band Base Station Antennas,
2022
Syracuse University
Mutual Coupling Reduction Techniques For Multi-Band Base Station Antennas, Evan Christopher Wayton
Dissertations - ALL
This dissertation proposes antenna design techniques which suppress mutual coupling in densely populated dual-polarized broadband multi-band base station antenna (BSA) arrays for improved radiation characteristics. Array face densification without the proposed techniques leads to undesirable interactions between arrays and radome cover. This research is supported by extensive full-wave electromagnetic simulations, characteristic mode analysis, equivalent circuit models, and array theory. The results are validated through measurements of the radiation patterns and scattering parameters of fabricated prototypes.Upon excitation of a mid-band (MB) array, an electrically long low-band (LB) parasitic, necessary for broadband matching of the baseline LB dipole, exhibits dipole-like induced currents …
