Electromagnetics and Photonics Commons^™

Integration And Measurements Of A Ka-Band Interferometric Radar In An Airborne Platform, Rockwell B. Schrock

Masters Theses 1911 - February 2014

The Topographic Interferometry Mapping Mission (TIMMi) instrument is a unique millimeter wave interferometric radar system operating at 35 GHz (Ka-band). It was constructed in part to advance the technology readiness level of NASA’s Surface Water and Ocean Topography (SWOT) mission, a spaceborne platform that will globally map the altimetry of Earth’s water to gain insight into surface water interactions and dynamics. Previous ground deployments of TIMMi were successful in demonstrating the abilities of the system from a stationary platform. The next logical step was to move TIMMi closer to space by installing it on an airborne platform prove its capability …

A New Class Of Improved Bandwidth Planar Ultrawideband Modular Antenna (Puma) Arrays Scalable To Mm-Waves, John Logan

Masters Theses 1911 - February 2014

A new class of Planar Ultrawideband Modular Antenna (PUMA) arrays, termed PUMAv3, is introduced to offer improved performance and further meet demand needs for multifunctional systems. PUMAv3 extends the frequency scalability of PUMA arrays to mm-waves (approximately 50 GHz) and improves bandwidth by 50\% without the use of a matching network or external baluns. The major enabling technical innovation is the advent of a new common-mode mitigation mechanism that relies upon capacitively-loaded shorting vias to push broadside catastrophic resonances below the operating band without inhibiting low-end bandwidth performance. Ridged waveguide models are employed to explain the operational principles and accurately …

Implementation Of Dual-Polarization On An Airborne Scatterometer And Preliminary Data Quality, Jason Dvorsky

Masters Theses 1911 - February 2014

The Imaging Wind and RAin Profiler (IWRAP) is an airborne scatterometer system built and operated by University of Massachusetts Amherst's Microwave Remote Sensing Laboratory (MIRSL). The radar is seasonally deployed aboard one of the two National Oceanic and Atmospheric Administration (NOAA) WP-3D Orion ``Hurricane Hunter'' aircraft based out of MacDill AFB in Tampa, Florida. IWRAP is a dual-frequency, Ku- and C-band, scatterometer that uses two conically scanning antennas to estimate the ocean surface wind vectors as well as intervening rain profiles. Data that is gathered with IWRAP is used to improve current Geophysical Model Functions (GMF) or to help derive …

The Measurement Of Internal Temperature Anomalies In The Body Using Microwave Radiometry And Anatomical Information: Inference Methods And Error Models, Tamara V. Sobers

Masters Theses 1911 - February 2014

The ability to observe temperature variations inside the human body may help in detecting the presence of medical anomalies. Abnormal changes in physiological parameters (such as metabolic and blood perfusion rates) cause localized tissue temperature change. If the anatomical information of an observed tissue region is known, then a nominal temperature profile can be created using the nominal physiological parameters. Temperature-varying radiation emitted from the human body can be captured using microwave radiometry and compared to the expected radiation from nominal temperature profiles to detect anomalies. Microwave radiometry is a passive system with the ability to capture radiation from tissue …

The Radiation Quality Factor Of Vertically Polarized Spherical Antennas Above A Conducting Ground Plane, Hsieh-Chi Chang

Masters Theses 1911 - February 2014

The radiation quality factor of small vertically polarized antennas above a ground plane is investigated. Although the quality factor of small antennas in free space has been investigated extensively in the past, the exact effect of a conducting ground plane on the antenna bandwidth is not clearly understood. In this thesis, quality factors of vertically polarized antennas above a ground plane are computed and compared with their free-space counterparts. The theoretical results on quality factors are validated with simulations of electrically small spherical helix antennas.

Terahertz Imaging For Cancer Detection, Benjamin A. St. Peter

Masters Theses 1911 - February 2014

This project evaluates the ability of terahertz (THz) radiation to differentiate cancerous from non-cancerous human breast lumpectomy and mastectomy tissue. This is done by aiming a narrow-band THz beam at medical samples and measuring reflected power. THz images of specimens from Breast Conservation Surgery (BCS) were created using a gas laser source and mechanical scanning. The design and characterization of this system is discussed in detail. The images were correlated with optical histological micrographs of the same specimens and discrimination values of more than 70% were found for five of the six samples using Receiver Operating Characteristic (ROC) analysis.

On The Retrieval Of The Beam Transverse Wind Velocity Using Angles Of Arrival From Spatially Separated Light Sources, Shiril Tichkule

Masters Theses 1911 - February 2014

For optical propagation through the turbulent atmosphere, the angle of arrival (AOA) cross-correlation function obtained from two spatially separated light sources carries information regarding the transverse wind velocity averaged along the propagation path. Two methods for the retrieval of the beam transverse horizontal wind velocity, v_t, based on the estimation of the time delay to the peak and the slope at zero lag of the AOA cross-correlation function, are presented. Data collected over a two week long experimental campaign conducted at the Boulder Atmospheric Observatory (BAO) site near Erie, CO was analyzed. The RMS difference between 10 s estimates of …

Inversion Of Marine Radar Imagery To Surface Realizations And Dual-Polarization Analysis, Brian Paulsen

Masters Theses 1911 - February 2014

The ocean influences global weather patterns, stores and transports heat, and supports entire ecosystems. An area of interest is the relationship between the observed backscattered power received by a surface-based marine radar and the ocean surface topography. Current methods for obtaining surface elevation maps involve either in situ devices, which only provide point measurements, or an interferometric radar, which can be costly. During the late 1990's and early 2000's a radar was built at UMass, called the Focused Phased Array Imaging Radar II (FOPAIR II), and deployed at a several locations. A method is discussed to determine a transfer function …

Development, Deployment, And Characterization Of A Ku-Band Interferometer, Anthony Swochak

Masters Theses 1911 - February 2014

Space-borne radar interferometry provides a global vantage point to understand climate change, global weather phenomenon, and other Earth dynamics. For climate change observations, space-borne interferometers can be utilized to relate ocean topography to temperature, thus providing a global map of ocean temperatures. Since the oceans are in constant motion, a single-pass interferometer is needed to successfully make these measurements of ocean height. The feasibility of a single-pass measurement is dependent on the physical size of the instrument, hence it is cheaper and more practical to launch a small, light weight instrument into space. Since instrument size scales inversely with operating …

Terahertz Radiation From Single Walled Carbon Nanotubes, Martin M. Muthee

Masters Theses 1911 - February 2014

The Terahertz region of the electromagnetic spectrum is the region between microwaves and infra-red, dubbed the terahertz 'gap' due to its relative underdevelopment in terms of technology. This region is marked by expensive and inconvenient sources that are bulky or that require cryogenic cooling for normal operation, therefore creating a need for cheap and easy to use terahertz sources.

Carbon nanotubes have received considerable attention since their discovery due to their unique physical and electronic properties. Many applications have been proposed using especially Single-Walled Carbon Nanotubes (SWCNTs), and a number of commercial technologies exist. In this work, we have proposed …

Transmission-Line Metamaterial Design Of An Embedded Line Source In A Ground Recess, Caglar D. Emiroglu

Masters Theses 1911 - February 2014

A transmission-line metamaterial design of a material-embedded electric line source radiating inside a ground recess is investigated. The media embedding the recessed line source are designed such that the embedded current creates the same radiation pattern as a line source over a flat conducting ground plane. Transmission-line metamaterial unit cell designs for the embedding media obtained from the transformation electromagnetics design technique are shown. The metamaterial design of the overall embedded source configuration is numerically tested using circuit simulations. It is shown that the embedded-source design creates the same radiation characteristics as the line source above a flat ground plane …

Resonant Antennas Based On Coupled Transmission-Line Metamaterials, Christopher S. Merola

Masters Theses 1911 - February 2014

A novel microstrip patch antenna topology is presented for achieving a dual-band response with arbitrarily closely spaced resonances. This topology is based on a coupled transmission line structure in order to take advantage of the separation in propagation constants for parallel (even-mode) and anti-parallel (odd-mode) current modes. Applying a metamaterials inspired design approach, periodic reactive load­ings are used to design the underlying transmission line to have specific propagation constants necessary to realize a desired separation between two resonant frequencies. Using a single probe feed for a finite coupled line segment, both even-and odd-mode resonances can be excited to radiate efficiently …

Electromagnetic Modeling Of Photolithography Aerial Image Formation Using The Octree Finite Element Method, Seth A. Jackson

Masters Theses 1911 - February 2014

Modern semiconductor manufacturing requires photolithographic printing of subillumination wavelength features in photoresist via electromagnetic energy scattered by complicated photomask designs. This results in aerial images which are subject to constructive and destructive wave interference, as well as electromagnetic resonances in the photomask features. This thesis proposes a 3-D full-wave frequency domain nonconformal Octree mesh based Finite Element Method (OFEM) electromagnetic scattering solver in combination with Fourier Optics to accurately simulate the entire projection photolithography system, from illumination source to final image intensity in the photoresist layer. A rapid 1-irregular octree based geometry model mesher is developed and shown to perform …

Calibration Of The Umass Advanced Multi-Frequency Radar, Matthew Mclinden

Masters Theses 1911 - February 2014

The Advanced Multi-Frequency Radar is a three-frequency system designed and built by the University of Massachusetts Microwave Remote Sensing Lab (MIRSL). The radar has three frequencies, Ku-band (13.4 GHz), Ka-band (35.6 GHz), and W-band (94.92GHz). The additional information gained from additional frequencies allows the system to be sensitive to a wide range of atmospheric and precipitation particle sizes, while increasing the ability to derive particle microphysics from radar retrievals.

This thesis details the calibration of data from the Canadian CloudSat/CALIPSO Validation Project (C3VP) held during January 2007 in Ontario, Canada. The calibration used internal calibration path data and was confirmed …

Fast Parameter-Space Sweep Of Wideband Electromagnetic Systems Using Bt-Pod, Wei Wang

Masters Theses 1911 - February 2014

Modeling and design of high frequency electronic systems such as antennas and microwave devices require the rigorous numerical solution of Maxwell’s equa- tions. The frequency-domain (time-harmonic) tangential vector finite element method (TVFEM) for Maxwell equations results in a second-order dynamical electromagnetic model that must be repeatedly solved for multiple frequencies, excitation or material parameters each design loop. This leads to extremely long design turnaround that often is not optimal. This work will propose an accurate, error controllable and ef- ficient multi-parametric model order reduction scheme that significantly accelerate these parameters sweep. At the core of this work is the proper …

Design And Development Of A Ka-Band Interferometer For Cryospheric Applications, Harish K. Vedantham

Masters Theses 1911 - February 2014

Topographic maps of the earth are essential to geographic and earth science studies. In particular, mapping and estimating physical parameters of the earth’s water and ice cover are critical to global climate studies. Among these, snow, ocean and fresh water topography, snow wetness and water equivalent are of immediate interest to the scientific community.

Challenges in the instrument development and deployment posed by these required measurements are twofold. Firstly, these measurements are required to have global coverage, yet maintain stringent spatial resolution and accuracy margins. Secondly, snow topography measurement requires minimal electromagnetic wave penetration through snow, hence requiring the use …

A Study Of A Reimaging System For Correcting Large-Scale Phase Errors In Reflector Antennas, Eugene F. Lauria

Masters Theses 1911 - February 2014

This thesis investigates a new approach for dealing with the adverse effects of large-scale deformations in the main reflector of large Cassegrain antennas. In this method, the incident aperture distribution is imaged onto a tertiary focal plane. This is accomplished by using an optical imaging system consisting of a lens mounted behind the Cassegrain focus of the antenna. The lens forms a real image of the product of the incident aperture distribution and the pupil function of the antenna. The pupil function describes the profile of the main reflector of the antenna. If the incident aperture distribution is a plane …