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Special Report
Bradley Fellow/Scholar Alumni

 April 2001

 

Electromagnetics Research

Associated Laboratories and Centers:
Virginia Tech Antenna Group
ElectroMagnetic Interactions Laboratory (EMIL)
Fiber & Electro-Optics Research Center (FEORC)
Optical Image Processing Laboratory
Optical Sciences and Engineering Research Center (OSER)
Photonics Laboratory
Time Domain Laboratory

Electromagnetics research at Virginia Tech ranges from the fundamental to the very applied. Research topics include antennas, wireless applications, fiber optics, sensors and materials, propagation, optical image processing, upper atmospheric processes, scattering, transients, as well as microwave modeling, measurements, design, and materials.

Representative Research Projects in electromagnetics.

 

ElectroMagnetic Interactions Laboratory (EMIL)

ECE Faculty
Gary Brown, Director
Robert Adams
Bradley Davis

EMIL continues to work toward (a) obtaining a better understanding of how electromagnetic waves interact- with the natural environment and (b) how to best model this interaction. On the applications side, EMIL is assisting NASA Goddard Space Flight Center in trying to determine the source of anomalous data coming from the TOPEX/POSIEDON radar altimeter. This same sensor first detected the onset of El Niño. Preliminary indications are that the sources of the anomalous data are the relatively smooth patches on the ocean's surface that can frequently be seen from aircraft.

The problem that EMIL is primarily involved in is modeling the effect of these on the radar, and designing ways to circumvent their contamination of the radar data. On the fundamental side, EMIL has completed a study of scattering by wedge-like perturbations on a planar surface for the purpose of quantifying just how much the wedge tip contributes to the scattering of the incident em wave. Although the primary intent of this study was to improve models for propagation over rough surfaces for the U.S. Army, an unexpected auxiliary result was some new insight gained into the low grazing backscattering problem.

In particular, a new source of polarization dependant low grazing angle backscattering was found. EMIL is also conducting an investigation for the U.S. Air Force on predicting when a radar can penetrate a canopy of foliage, propagate down to a target on the surface, and scatter back up to the radar with an identifiable and a detectable signal level. EMIL has developed one model that is particularly amenable to "calibration" by comparing the model with actual radar data. Such "calibration" ensures that the parameters in the model are derived from (limited) actual data with the aim of using the model to predict penetration over other similar regions. In a program sponsored by the Office of Naval Research, EMIL has developed a model for low-grazing electromagnetic wave scattering by the ocean surface that includes the refraction in the atmosphere above the surface. The inclusion of both refractivity and surface roughness is done in an exact manner and is particularly important in ship self-defense.

Propagation in an urban environment with particular emphasis on wave diffraction in the off-specular direction by objects having sharp edges is a project being sponsored by the U.S. Army Research Office. EMIL researchers have also developed the only known model for the effects of roughness on diffraction of an electromagnetic wave by a rough knife-edge boundary. Finally, EMIL is conducting basic research on new models for wave scattering by two-dimensionally rough surfaces that are both robust in their range of applicability and fast in their implementation. These models build upon some unique mathematical capability that researchers in EMIL have developed for recasting conventional electromagnetic scattering problems into new forms that are much more amendable to efficient and robust solutions. This research is sponsored by the University of Delaware, under a U.S. Air Force MURI on Computational Electromagnetics.

 

The Fiber & Electro-Optics Research Center (FEORC)

ECE Faculty
Richard O. Claus, Director
Ira Jacobs
Roger Stolen

FEORC was founded at Virginia Tech by Virginia's Center for
Innovative Technology, primarily to provide university research to support development of the state's fiber optics industry. Over the past 15 years, the lightwave industry has spread across the entire state, including an area with a high concentration of businesses in the southwestern part of Virginia known as "Silica Valley." Since its inception, the Center has developed many intellectual properties that have been commercialized, including optical materials, devices, sensors and networks. FEORC developments during the past year include the incubation of a new research center on campus: the Optical Sciences and Engineering Research Center (OSER).

For several years, FEORC has collaborated with the Center for Transportation Research on the communications network for Virginia's "Smart Road." This multimillion-dollar testbed highway is finally a reality, and well equipped for many ITS (intelligent transportation systems) applications.

FEORC is currently involved in several new multidisciplinary programs including a university-sponsored ASPIRES program with the College of Veterinary Medicine for the optical detection of biological functions, and an industry- and government-sponsored program to develop new nanostructured electro-optic materials.

The Center's mission within the university community is to teach graduate and undergraduate students about optical materials and devices, instrumentation and communications systems through research projects and formal classroom and laboratory teaching. FEORC has the largest fiber optics research and instructional program in the United States.

Currently the Center has 20 full-time research staff members and more than 30 graduate students. Each year approximately 300 students take fiber optics related courses, such as fiber optics communications, networks and systems, polymer optoelectronic devices, fiber optic applications, and electrical theory, taught by three primary faculty members.

The Center's efforts to provide support to industry in the state have been successful and, over the years, have included cooperative efforts with more than 250 Virginia companies and providing the impetus for the establishment of 17 spin-off firms in Virginia and one in Minnesota.

 

Optical Image Processing Laboratory
T.-C. Poon, Director

The Optical Image Processing (OIP) Laboratory creates an
environment for progressive, practical scholarship in all aspects of hybrid (optical/electronic/digital) information processing technology. Its comprehensive academic research and education program complements the growing need for photonic instrumentation and the economic development of the electro-optics industry. The OIP Laboratory supports research in the areas of acousto-optics, optical scanning holography, 3-D microscopy, optical 3-D coding and decoding, 3-D display, and optical recognition of 3-D objects. Equipment includes two large vibration isolation optical tables with associated optical, mechanical, and electronic instrumentation. Specialized equipment includes an electron-beam-addressed spatial light modulator and an optically addressed spatial light modulator (long-term partnership loan from Hamamatsu Photonics K.K., Japan), and x-y optical scanning systems. The program of the OIP Laboratory actively encourages mutual collaboration with other research institutes. Typical sponsors include Army Research Office, Hamamatsu Corporation, National Science Foundation, NASA, National Institutes of Health, and the U.S. Navy.

Optical Sciences and Engineering Research Center (OSER)
Richard Claus, Associate Director

The Optical Sciences & Engineering Research Center (OSER) conducts research and engineering activities involving optics and other disciplines to create knowledge and technology to benefit the medical, biomedical and veterinary fields, while supporting the practical goals of improving services and reducing the costs of health care.

Established in 2000, OSER investigates advanced laser surgery optics, biocompatible material for implants, and diagnostic patches and other diagnostic and drug delivery tools. The Center employs optics to provide new biological research tools for visualization, measurement, analysis and manipulation. The Optical Sciences and Engineering Research center (OSER) is part of a unique collaboration among Virginia Tech, the Carilion Health System and the University of Virginia. The umbrella organization for this partnership is the Carilion Biomedical Institute in Roanoke, Virginia. The institute is primarily responsible for prototype development, commercialization and the spin-off of technology created by its supporting research centers at the two universities: OSER at VT and the Medical Automation Research Center (MARC) at UVa.

Research center activities range from basic biomedical research to experimental device development and laboratory demonstrations. Results of center R&D activities are transferred to the institute for prototype and product development leading to new biotechnology start-up companies and the creation of new jobs in Virginia.

Photonics Laboratory
http://photonics.ece.vt.edu/

ECE Faculty
Anbo Wang, Director
Ahmad Safaai-Jazi
Russell May

The Photonics Laboratory, created in 1997, is dedicated to education and research in photonics, the technology of generating, harnessing, and manipulating light to perform useful functions. The 8,000 square ft. office and laboratory space and more than $2 million annual external funding supports research in fiber optics for sensing, communications, and biophotonics.

The Photonics Laboratory is currently the largest university optical fiber sensor research group in the country. The research in this area is focused on innovative sensors for harsh environment applications where conventional measurement devices are difficult to apply. The research covers all the major aspects concerning fiber sensors, including materials, new sensing mechanisms, fiber modifications, advanced packaging, optoelectronic signal processing, and instrumentation systems. The research has recently yielded a number of successful new sensors capable of operation at temperatures as high as 1700°C. Research also includes investigation of various methods for multiplexing of thousands of sensor elements along a fiber for distributed measurement.

In communications, the research is concentrated on special fibers and passive fiber components for long-haul and metro systems. Representative work in special fibers includes large effective area fiber for nonlinearity reduction, hermetic fiber for long-term 'dry' operation, lateral-to-longitudinal coupling fiber for off-axis broadband signal transmission, and photonic crystal (holey) fibers for better control of dispersion and modal characteristics. In components, the work is directed toward the design and development of low-cost devices for metro systems based on fiber modifications, thermal fusion and/or thin film technology.

In biophotonics, the work covers 3-D topographic mapping, surface temperature measurement, and early-stage identification of molecular signatures of cancers. The center has developed various key technologies for 3-D surface mapping, including PM fiber pigtailed high power diode laser systems, miniaturized light illumination modules for generation of structured light patterns, fiber-based self-calibrated mapping systems, and image processing algorithms. 3-D thermal imaging is also demonstrated based on the combination of commercially available thermal imaging devices with the developed 3-D mapping technology. Currently the center is collaborating with Virginia Tech's Veterinary School to demonstrate a new method for identification of molecular signatures of cancers for non-invasive early cancer detection and diagnosis.

Photonics Laboratory researchers have joined the fight against cancer. Visiting scholar Bing Qi showed that the Raman peaks corresponding to the resonance of b-carotene have significantly different levels in healthy people and in those with cancer. In order to develop a blood serum test based on this work, the Photonics Laboratory is developing the Raman spectrometer necessary for sera measurement, along with a signal acquisition and analysis unit so that data can be processed on a personal computer.

Time Domain & RF Measurement Laboratory

Sedki M. Riad, Director

The laboratory's main research interest is in wideband measurements and characterization problems using time domain and frequency domain techniques. This includes the development of the measurement techniques; the characterization and modeling of devices, networks, or materials; the development of the necessary signal processing and data reduction methods; and the design and construction of related measurement instrumentation and setups. The laboratory contains facilities for wideband measurements from DC into the microwave and millimeter wave (70 GHz) frequency regions. This facility enables wideband measurements in both the time domain and the frequency domain.

Virginia Tech Antenna Group (VTAG)
http://antenna.ece.vt.edu

ECE Faculty
William A. Davis, Acting Director
Ahmad Safaai-Jazi
Sanjay Raman
Warren L. Stutzman
VTAG Affiliates
Northrop Grumman
Turbowave

The Antenna Group performs research on new antenna geometries, analysis methods, and measurement techniques, working closely with industry and government to meet their needs. Several new antennas have been developed and are being used on a variety of applications. The recent advances in antenna research include:

· VTAG, in cooperation with MPRG, produced significant results for two smart antenna experiment systems. The smart handheld terminal test bed investigated antenna diversity and beamforming with up to four antennas. It was found that significant signal improvement and interference rejection is possible with a compact antenna configuration.

· The second smart antenna experiment uses a base station on the roof of Whittemore Hall. Three forms of antenna diversity (spatial, polarization, and angle) were investigated simultaneously with a mobile transmitter operating at points on campus. All three diversity techniques were found to be very effective in reducing signal fading.

· Wideband antenna research sponsored by the Navy and Harris Corp. resulted in the invention and patent disclosure for the Fourpoint Antenna. This antenna is capable of 3:1 bandwidth in a low-profile, compact package. The application being pursued is for dual polarized base station antennas that cover from cellular through and above PCS frequencies in a single antenna. This reduces costs and hardware mounted on the tower.

· A patent disclosure was filed for a new antenna for handsets. The Wideband Compact PIFA Antenna has up to 50% bandwidth with a size that fits inside handheld terminals. This antenna can support multiple frequency bands.

The laboratory continues to expand its technology base and facilities. Efforts currently include new measurement systems and methods, evaluation of large electromagnetic codes, and a new emphasis on embedded antennas for use in handsets and mobile radio applications. In 2000, the Group began full use of its new $500,000 tapered anechoic chamber. The chamber includes both far-field and near-field measurement equipment. VTAG continues to use its roof top antenna range also.

 

Representative Research Projects in Electromagnetics

Advanced Propagation Modeling for Military Communications
EM Scatter Modeling in Support of Space Sensing
MURI95: Mathematical and Numerical Methods for Analysis and Design of EM Fields
FOPEN Modeling for Target Detection
Airborne Radar Waveform Returns from Foliage Covered Terrain
System Study of Optical Fiber Use in Automobiles
Analysis, Design, and Performance Evaluation of Optical Fiber Spectrum-Sliced
Twisted-Pair Cable Measurements for Computer Networks
Computer Networks Loop Reconstruction Using Time Domain Reflectometry
Characterization and Applications of Substrate Material Systems and Fabrication Technologies
Three-dimensional Optical Pattern recognition
Study of Spatial Light Modulators with Applications to 3-D Image Projection and Display
3D Imaging by Novel Annular Illumination
REU Supplement: 3-D Optical Pattern Recognition
Microwave Reprocessing of Thermal Runaway Materials
Theoretical and Simulation Studies of Stimulated Radiation During Ionospheric Heating
Theoretical and Simulation Studies of Expanding Ionospheric Dust Clouds
Research into Signal Recovery Algorithms in Support of Spectral Spatial Interference Cancellation Systems (SSICS): Phase II Research Effort
NAVCIITI Multifunctional Antennas
Sensors for Harsh Environments
Optical Fiber Strain Sensor Instrumentation for High Temperature Aerospace Structural Monitoring
Optical Fiber Sensor Technologies for Efficient Economic Oil Recovery
High-Temperature Optical Fiber Sensor Instrumentation for Gas Flow Monitoring in Gas Turbine Engines
Optical Fiber Sensor Technologies for Efficient and Economical Oil Recovery
Further Investigation of PD Detection Using Fiber Optic SCIIB Acoustic Sensors
Single-Crystal Sapphire Optical Fiber Sensor Instrumentation
Optical Fiber Sensor-Based Techniques for On-Line Detection and Location of Partial Discharges in Transformers
Optical Fiber Sensors for Infrasound Detection
High Temperature Optical Fiber Sensor Research
AASERT Program Support for Air Force Smart Metallic Structures Program
Fabrication of High-Nonlinearity Lead Iridium Phosphate Glass Optical Fibers
Fiber Gratings for High Power Laser Applications
Raman Amplification in Optical Fibers
Electrostatically Self-Assembled Multifunctional Materials and Structures
Bulk Optic Magnetic Field Sensors
ESA Processes for Fabrication of MEMS Materials and Devices
Feasibility Study of Self-Assembling Retinal Protein-Based Optoelectronic Devices
Data Driven Device Fabrication by ESA Processing
Integrated Water Quality Monitoring System
NLO Thin films and Photonic Devices
Electrostatically Self-Assembled Multifunctional Materials and Structures
Linear and Nonlinear Optical Thin Films and Devices
Thin Film Coating Products for Spectacle lenses
Fiber Optic Model Force Balance System for Wind tunnels
Optical Materials and Device Testing Program
Molecular Nanocluster Synthesis
NAVCIITI Multifunctional Optical Display
ESA Processes for Synthesis of Electro-Optic Crystal Devices
Self Assembled Advanced Materials
High Performance Fiber-based Meteorological Sensors
Self-Assembled Coatings with Tailorable Optical Properties
Synthesis, Fabrication and Evaluation of Thin Film Materials by Self-Assembly
Self-Assembled Adaptive Optical Components
Optical Sciences Research
Fuel Analyzer for Multi-Fuel Engine Optimization
NLO Thin Films and Photonic Devices
Underwater Procurable Adhesive attachment System Development and Characterization
AASERT Optical Fiber Interconnects and Sensors for Power Electronic Building Blocks
Polarized, Kilowatt Level Fiber Lasers
Navy Collaborative Integrated Information Technology Initiative (NAVCIITI)

 

The Bradley Department
of Electrical and Computer Engineering
Virginia Tech


Last Updated, July 15, 2001
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