A5016932012- Optical Coatings and Gratings
- Advanced Antenna and Metasurface Technologies
- Photonic and Optical Devices
- Microwave Engineering and Waveguides
- Photonic Crystals and Applications
- Antenna Design and Analysis
- Electromagnetic Simulation and Numerical Methods
- Electromagnetic Scattering and Analysis
- Metamaterials and Metasurfaces Applications
- Additive Manufacturing and 3D Printing Technologies
- Near-Field Optical Microscopy
- Cardiac Arrhythmias and Treatments
- Advanced optical system design
- Terahertz technology and applications
- Cardiac electrophysiology and arrhythmias
- Atrial Fibrillation Management and Outcomes
- Energy Harvesting in Wireless Networks
- Ultrasound and Hyperthermia Applications
- Cardiac pacing and defibrillation studies
- Optical Polarization and Ellipsometry
- Ocean Waves and Remote Sensing
- Plasmonic and Surface Plasmon Research
- Advanced Materials and Mechanics
- Underwater Acoustics Research
- Antenna Design and Optimization
University of Delaware
2016-2025
South College
2019
Naval Surface Warfare Center
2004-2016
Catholic University of America
2001-2010
University of America
2000-2009
University of Pennsylvania
1992-2003
Allegheny College
2001
This study analyzed the influence of electrode geometry, tissue-electrode angle, and blood flow on current density temperature distribution, lesion size, power requirements during radio-frequency ablation. The authors used validated three-dimensional finite element models to perform these analyses. They found that use an electrically insulating layer over junction between catheter body reduced chances charring coagulation. a thermistor at tip ablation electrodes did not affect distribution....
We apply boundary integrals to the analysis of diffraction from both conductive and dielectric diffractive optical elements. Boundary integral uses form wave equation describe induced surface distributions over a element. The are used determine diffracted fields anywhere in space. In contrast other vector techniques, methods not restricted infinitely periodic structures but extend finite aperiodic as well. element method solve equations validate its implementation by comparing with...
BACKGROUND This study was designed to examine the bulk electrical properties of myocardium and their variation with evolution infarction after coronary occlusion. These may be useful in distinguishing between normal, ischemic, infarcted tissue on basis electrophysiological parameters. METHODS AND RESULTS The impedance myocardial studied a sheep model infarction. animal involved one-stage ligation left anterior descending second diagonal arteries at point 40% distance from apex base. By use...
We demonstrate a new method for realizing Luneburg lens antennas with nearly continuously graded permittivity profiles in three dimensions. The combines fused filament fabrication, ubiquitous additive manufacturing technique, an effective media approach that employs space-filling curves. experimentally validate our design methodology by fabricating and characterizing two lenses designed to operate at separate frequency bands (26-40 GHz 70-110 GHz) antenna gains of 20 24 dBi, respectively....
Abstract The gradient-index (GRIN) Luneburg lens antenna offers significant benefits, e.g. high aperture efficiency, low-power, minimal cost, wide beam scanning angle and broad bandwidth, over phased array antennas reflector antennas. However, the spherical shape of geometry complicates integration standard planar feed sources poses implementation challenge. To eliminate mismatch problem, quasi-conformal transformation optics (QCTO) method can be adopted to modify lens’ surface into a one....
In this paper, we present a numerical model for evaluating tissue heating during magnetic resonance imaging (MRI). Our method, which included detailed anatomical of human head, calculated both the electromagnetic power deposition and associated temperature elevations an MRI head examination. Numerical studies were conducted using realistic birdcage coil excited at frequencies ranging from 63 to 500 MHz. The was validated experimentally analytically. experimental validation performed MR test...
ABSTRACT This study presents the development of a novel leaky wave antenna (LWA) that utilizes broad impedance modulation range. was achieved through introduction Rogers Corporation's Radix UV‐curable resin, which offers controlled dielectric constant and low electromagnetic loss. Optimized for Digital Light Processing with Fortify three‐dimensional printer, this resin enabled fabrication metasurface modulated surface via two parameters: conductive patch dimension substrate thickness. LWA...
A new method for synthesizing broadband antireflective (AR) surfaces at microwave and millimeter wave frequencies is demonstrated. The AR surface, we call an inverse motheye, was formed by machining a multi-layer grating of subwavelength circular holes into non-absorptive dielectric. This created low reflected energies (<; - 30 dB) over reasonably large bandwidths incidence angles. An optimization algorithm, based on direct pattern search, integrated with rigorous electromagnetic model used...
A low-profile antenna that includes an integrated artificial magnetic conducting (AMC) ground plane is presented and fully fabricated using multi-material additive manufacturing. It shown combining standard fused deposition modelling with conductive micro-dispensing printing enable one to realise mechanically robust systems contain spatially variable dielectric properties intricate three-dimensional networks. To illustrate this capability, a designed, fabricated, experimentally validated,...
Abstract We demonstrate a new method for realizing modified Luneburg lens antennas with nearly continuously graded permittivity profiles in three‐dimensions. The used quasi‐conformal transformation optics (QCTO) approach to modify the geometry and of spherical have flat surface convenient integration antenna feeds. was then fabricated using Fused Deposition Modeling (FDM) printing an effective media that employs space‐filling curves. validated by designing fabricating designed operate...
A conformal metasurface antenna exhibiting a pencil beam radiation pattern at 10.0 GHz has been designed using the Voronoi partition approach and fabricated on Kahu uninhabited aerial system (UAS) fuselage. Two manufacturing methods are presented compared. The first utilized three-axis Trotec fiber laser to etch flattened geometry in copper foil. etched was then "stretched" over UAS geometry. second 6-axis nScrypt (retrofitted with an IDS aerosol jetting tool) conformally print directly An...
The electrocatalytic oxygen evolution reaction (OER) is important for many renewable energy technologies. Developing cost-effective electrocatalysts with high performance remains a great challenge. Here, we successfully demonstrate our novel interface catalyst comprised of Ni3Fe1-based layered double hydroxides (Ni3Fe1-LDH) vertically immobilized on two-dimensional MXene (Ti3C2Tx) surface. Ni3Fe1-LDH/Ti3C2Tx yielded an anodic OER current 100 mA cm–2 at 0.28 V versus reversible hydrogen...
We present an optimization-based synthesis algorithm for the design of diffractive optical elements (DOE's) that are finite in extent, have subwavelength features, and aperiodic. The nature DOE's precludes use scalar diffraction theory, their extent aperiodic prevents coupled-wave analysis. To overcome these limitations, we apply boundary element method (BEM) as propagation model algorithm. However, computational costs associated with conventional implementation BEM prevent realistic...
An analytical method for determining the optimal reflection phase of an electromagnetic band gap (EBG) ground plane to match a low profile dipole antenna is introduced. Image theory used incorporate near field coupling between and plane. The main contribution this paper show that EBG can be determined at discrete frequencies where theoretically perfect return loss occurs. then obtained over wider frequency interest related antenna's given feed impedance height above EBG. resulting as...
Many applications require the ability to image a scene in several different narrow spectral bands simultaneously. Conventional multi-layer dielectric filters control of film thickness change resonant wavelength. This makes it difficult fabricate mosaic multiple band transmission monolithically. We adjusted filter by drilling periodic array subwavelength holes through stack. Multi-band photonic crystal were modeled and optimized for specific case filtering six optical on single substrate....