| Linear Transceiver Design for Interference Alignment: Complexity and Computation |
JUL 2010 |
19 pages |
| Authors:
Meisam Razaviyayn; Maziar S. Boroujeni; Zhi-Quan Luo; MINNESOTA UNIV MINNEAPOLIS DEPT OF ELECTRICAL AND COMPUTER ENGINEERING
|
 | Consider a MIMO interference channel whereby each transmitter and receiver are equipped with multiple antennas. The basic problem is to design optimal linear transceivers (or beamformers) that can maximize system throughput. The recent work [1] suggests that optimal beamformers should maximize the total degrees of freedom and achieve interference alignment in high SNR. In this paper we first consider the interference alignment problem in spatial domain and prove that the ... |
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| 3-dB Bandwidth Enhancement via the Gain-Lever Effect in Quantum-Dot Lasers |
JUL 2010 |
11 pages |
| Authors:
Y. Li; Nader A. Naderi; Luke F. Lester; Vassilios Kovanis; AIR FORCE RESEARCH LAB WRIGHT-PATTERSON AFB OH AEROSPACE COMPONENTS AND SUBSYSTEMS TECHNOLOGY DIVISION
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| We investigate the small-signal modulation response of two-section, gain-lever, quantum-dot semiconductor lasers. A three-pole modulation function is derived from a 3-D set of rate equations, and a 70% 3-dB bandwidth enhancement is computed and experimentally realized in an undoped quantum-dot gain-lever laser under extreme asymmetric-bias conditions. Finally, it is demonstrated that the 3-dB bandwidth is three times the free-running relaxation oscillation frequency in these types of laser structures, as opposed ... |
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| A Nonlinear Optimal Control Design using Narrowband Perturbation Feedback for Magnetostrictive Actuators |
Jul 2010 |
26 pages |
| Authors:
William S Oates; Rick Zrostlik; Scott Eichhorn; Ralph Smith; NORTH CAROLINA STATE UNIV AT RALEIGH CENTER FOR RESEARCH IN SCIENTIFIC COMPUTATION
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| Nonlinear optimal and narrowband feedback control designs are developed and experimentally implemented on a magnetostrictive Terfenol-D actuator. The nonlinear optimal control design incorporates a nonlinear and hysteretic ferromagnetic homogenized energy model within an optimal control formulation to reduce displacement tracking errors and increase bandwidth. Improvements in robustness in the steady-state regime are achieved by utilizing narrowband feedback. A narrowband filter is implemented by treating the nonlinear and hysteretic magnetostrictive constitutive ... |
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| Compressive Signal Processing |
30 Jun 2010 |
8 pages |
| Authors:
Richard G Baraniuk; RICE UNIV HOUSTON TX
|
| In this project, we explored the theory and applications of compressive sensing (CS), in which non-adaptive, linear projections are used to acquire an efficient representation of a compressible signal or image directly using just a few measurements. The signal is then reconstructed by solving a tractable inverse problem. CS offers a fresh approach to framing and solving a number of timely and challenging problems in signal processing that relate directly ... |
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| Experiments in Weight Design for a Sombrero Array Pattern |
25 Jun 2010 |
71 pages |
| Authors:
Kelly R McPhail; Jeffrey O Coleman; Dan P Scholnik; NAVAL RESEARCH LAB WASHINGTON DC ADVANCED RADAR SYSTEMS BRANCH
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| There is an interest in developing a transmit array taper that illuminates both a highly directive cluster of receive beams and a broad region of the sky at a level that can support a ubiquitous radar function. This report provides experimental optimization results of a sombrero-shaped amplitude array taper that can be used to implement two simultaneous functions of this type. The amplitude tapers are optimized in two ways: boresight ... |
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| Hybrid Cable Antenna for High Frequency Band |
09 Jun 2010 |
12 pages |
| Authors:
David A Tonn; DEPARTMENT OF THE NAVY WASHINGTON DC
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| A hybrid cable antenna includes a first cable antenna that is buoyant and unloaded for operation in a lower portion of the high frequency band. At least one second cable antenna is serially and electrically coupled to the first cable antenna. Each second cable antenna is buoyant and loaded for operation in a portion of the high frequency band that is above the lower portion of the high frequency band. ... |
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| An Examination of the Feasibility of Ultrasonic Communications Links |
Jun 2010 |
62 pages |
| Authors:
David Tofsted; Sean O'Brien; Sean D'Arcy; Edward Creegan; Scott Elliott; ARMY RESEARCH LAB WHITE SANDS MISSILE RANGE NM COMPUTATIONAL AND INFORMATION SCIENCE DIRECTORATE
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| A study is performed to consider the feasibility of using the ultrasonic band just above the normal adult audio frequency range (20-25 kHz) for low data rate signaling. In this band several features of interest are explored and a potential application (Identification Friend-or-Foe [IFF]) is highlighted. A key finding is that the data transmission rate is restricted in the presence of multipathing effects. Data transmission rates in the 300-baud range ... |
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| Rare-earth Doped GaN - An Innovative Path Toward Area-scalable Solid-state High Energy Lasers Without Thermal Distortion (2nd year) |
Jun 2010 |
28 pages |
| Authors:
Michael Wraback; Mark Dubinskiy; ARMY RESEARCH LAB ADELPHI MD SENSORS AND ELECTRON DEVICES DIRECTORATE
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| In situ neodymium (Nd) doping of gallium nitride (GaN) and aluminum nitride (AlN) by plasma-assisted molecular beam epitaxy (PA-MBE) has been demonstrated for the first time. For GaN, Nd doping as high as 8 at.% has been demonstrated, with no evidence of phase segregation identified by x-ray diffraction (XRD) for Nd up to 1 at.%. The strongest roomtemperature luminescence was observed for a doping level between 0.1-1 at.%. The Stark ... |
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| Low-cost Electronically Scanning Antenna with Randomly Selected Delay Line Lengths |
Jun 2010 |
26 pages |
| Authors:
Geoffrey Goldman; ARMY RESEARCH LAB ADELPHI MD SENSORS AND ELECTRON DEVICES DIRECTORATE
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| A radar architecture that requires a single analog-to-digital converter and no active phase shifters was developed that can electronically search a three-dimensional (3-D) volume and provide range resolution and angular resolution proportional to the Rayleigh criterion for a given bandwidth and aperture size. The architecture is based on a frequency scanning antenna feed with delay lines whose lengths are randomly selected in combination with digital signal processing algorithms. I investigated ... |
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| Design and Measurements of a Hybrid RF-MEMS Reconfigurable Loop Antenna on a Flexible Substrate (PREPRINT) |
Jun 2010 |
7 pages |
| Authors:
Nelson Sepulveda; Rafael A Rodriguez-Solis; Dimitrios E Anagnostou; John L Ebel; PUERTO RICO UNIV MAYAGUEZ DEPT OF ELECTRICAL AND COMPUTER ENGINEERING
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| Reconfigurability in an antenna system is a desired characteristic that has been the focus of much research in recent years. In this work, a hybrid reconfigurable RF-MEMS loop antenna was designed, fabricated (on a flexible substrate) and measured. The design concepts and measurement results are presented and discussed. |
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| Predicting the Demand for Spectrum Allocation through Auctions (PREPRINT) |
Jun 2010 |
8 pages |
| Authors:
Y B Reddy; GRAMBLING STATE UNIV LA DEPT OF MATHEMATICS AND COMPUTER SCIENCE
|
| The projected rare resource spectrum generates high profits if utilized efficiently. The current static allocation lead the spectrum to underutilized with fixed income. Predicting the user requirement for spectrum and auctioning the spectrum helps to better serve the customers and at the same time increases the income. In this research we use the automated collaborative filtering model for predicting the customer requirement and then allocate the spectrum through auctions (bidding ... |
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| Multiple-Optimizing Dynamic Sensor Networks with MIMO Technology (PREPRINT) |
Jun 2010 |
13 pages |
| Authors:
Wei Chen; Miao He; Fletch Gregory; TENNESSEE STATE UNIV NASHVILLE
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| A Multiple-Input Multiple-Output (MIMO) transceiver provides extremely high spectral efficiencies by simultaneously transmitting multiple data streams in the same channel. Some research works have used MIMO technology to increase data rate or reduce energy consumption at communication links in wireless sensor networks. Since all layers of the protocol stack affect network performance, an efficient system should exploit the advantage of MIMO technology across all layers as well as the underlying ... |
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| High-Frequency Percussive Ventilation: Pneumotachograph Validation and Tidal Volume Analysis |
Jun 2010 |
8 pages |
| Authors:
Patrick F Allan; LANDSTUHL REGIONAL ARMY MEDICAL CENTER APO NEW YORK 09180 PULMONARY MEDICINE SERVICE
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| INTRODUCTION: High-frequency percussive ventilation (HFPV) is an increasingly used mode of mechanical ventilation, for which there is no proven real-time means of measuring delivered tidal volume (VT). OBJECTIVE: To validate a pneumotachograph for HFPV and then exploit flowsensor data to describe the behavior of both low-frequency and high-frequency breaths. METHODS: Sensor performance was gauged during changes in high-frequency and low-frequency rate and ratio, mean airway pressure, oxygen concentration, heated or ... |
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| High Terahertz Absorbing Nanoscale Metal Films for Fabrication of Micromechanical Bi-material THz Sensors |
Jun 2010 |
71 pages |
| Authors:
Christos Bolakis; NAVAL POSTGRADUATE SCHOOL MONTEREY CA
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| The terahertz (THz) region of the electromagnetic spectrum covers frequencies ranging from approximately 100 GHz to 10 THz. This region of the spectrum has not been fully utilized due to the lack of compact and efficient sources as well as detectors. The aim of the present research is to explore the use of thin metal films as high THz absorbing materials and determine their THz absorbing characteristics analytically as well ... |
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| Comparison of Gold/Platinum and Gold/Ruthenium Contacts on Piezoelectrically Actuated RF MEMS Switches |
Jun 2010 |
18 pages |
| Authors:
Robert Proie; Daniel Judy; Ronald G Polcawich; Jeffrey Pulskamp; ARMY RESEARCH LAB ADELPHI MD SENSORS AND ELECTRON DEVICES DIRECTORATE
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| Lead zirconate titanite (PZT) radio frequency (RF) microelectromechanical system (MEMS) switches developed at the U.S. Army Research Laboratory (ARL) were fabricated with half of the switches on each wafer-approximately 30 switches-using the typical gold/platinum contacts and using gold (Au)/ruthenium (Ru) contacts for the other half. We measured several important parameters using an Electroglass automated probe station, including contact resistance, actuation voltage, and bias current. The switches were cycled a number ... |
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| Frequency Domain Beamformer for a 3-D Sediment Volume Imaging Synthetic Aperture Sonar |
Jun 2010 |
5 pages |
| Authors:
Jonathan R Magoon; Matthew A Nelson; Daniel D Sternlicht; NAVAL SURFACE WARFARE CENTER PANAMA CITY FL
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| A frequency domain beamforming approach is described for 3-D sediment volume imaging synthetic aperture sonars (SAS). The beamformer, designed for systems with receiver arrays oriented transverse to the vehicle, performs standard delay and sum processing for each ping in the across-track direction followed by multi-ping synthetic aperture processing of elevation planes in the along-track direction. The beamformer can be run repeatedly with varying along-track squint angles revealing aspect-dependent target features. ... |
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| Multipath Cancellation Using a Maximum Likelihood Metric Space |
Jun 2010 |
5 pages |
| Authors:
John E Piper; NAVAL SURFACE WARFARE CENTER PANAMA CITY FL
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| Multipath signals occur in many sonar, radar, and communication applications. It is, of course, generally desirable to eliminate these unwanted signals. Traditional array signal processing techniques often have trouble eliminating these signals when only a small number of array elements are available. The maximum likelihood method explicitly models multiple signals in its mathematical construction. This feature effectively opens up a multidimensional space that allows the desired direct path signal to ... |
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| On the Satisfaction of Modulus and Ambiguity Function Constraints in Radar Waveform Optimization for Detection |
Jun 2010 |
164 pages |
| Authors:
Lee K Patton; WRIGHT STATE UNIV DAYTON OH
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| We consider the design of radar systems that are capable of using knowledge of their interference environment to dynamically design transmit waveforms that afford optimum signal-to-interference-plus-noise ratio while satisfying modulus and ambiguity function constraints. We begin by establishing the inextricable nature of modulus constraints in the waveform optimization problem. We then extend the state of the art in waveform optimization to accommodate these constraints. This is done by solving a ... |
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| Frequency Agile Lidar Receiver for Chem-Bio Sensing |
Jun 2010 |
5 pages |
| Authors:
Bogdan R Cosofret; Ian M Konen; Ankit H Patel; Patrick Cobler; Raphael P Moon; Jeffrey L Ahl; PHYSICAL SCIENCES INC ANDOVER MA
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| Physical Sciences Inc. (PSI), in conjunction with its subcontractor, VTech Engineering Corp., developed an ultra low noise receiver module (RM) for direct detection LWIR LIDAR systems. The receiver module is compatible with emerging LWIR source technologies, e.g., optical parametric amplifier-based sources, as well as existing frequency-agile CO2 laser technology. In this paper we present RM performance attributes based on characterization experiments performed in the laboratory, as well as part of ... |
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| Correlation of In Situ Measurements of Plasma Irregularities with Ground-Based Scintillation Observations |
Jun 2010 |
7 pages |
| Authors:
P A Roddy; D E Hunton; J O Ballenthin; K M Groves; AIR FORCE RESEARCH LAB HANSCOM AFB MA
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| We present here the first comparison of in situ ion density fluctuations measured by the Planar Langmuir Probe on Communication Navigation Outage Forecasting System (C/NOFS) with coincident ground-based measurements of scintillation from the Scintillation Decision Aid (SCINDA) network and coherent scatter radar located on Christmas Island (3 N, 157 W) over a 15 month period from May 2008 through June 2009. The Planar Langmuir Probe on C/NOFS measures absolute ion ... |
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| Development of RF Sensor Based on Two Cell SQUID |
JUN 2010 |
13 pages |
| Authors:
Alexey Ustinov; Ming He; KARLSRUHE UNIV (GERMANY F R)
|
| In this project, we proposed to develop and investigate a sensitive microwave sensor based on a two-cell SQUID by imitating the operational principle of the fly's ears. The fly ormia shows astonishing localization ability with its tiny hearing organ. In this report, we show first measurement results based on several available Josephson junction (JJ) circuits. We investigated the current-voltage characteristics as a function of external magnetic field. We have also ... |
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| The TANAMI Program |
JUN 2010 |
5 pages |
| Authors:
Roopesh Ojha; Matthias Kadler; Moritz Boeck; Faith Hungwe; Cornelia Mueller; Joern Wilms; Eduardo Ros; NAVAL OBSERVATORY WASHINGTON DC
|
| The TANAMI (Tracking AGN with Austral Milliarcsecond Interferometry) program provides comprehensive VLBI monitoring of extragalactic gamma-ray sources south of declination -30 degrees. Operating at two radio frequencies (8 and 22 GHz), this program is a critical component of the joint quasi-simultaneous observations with the Fermi Gamma-ray Space Telescope and ground based observatories to discriminate between competing theoretical blazar emission models. We describe the TANAMI program and present early results on ... |
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| Compensating Losses in Optical Negative-Index Materials and New Frontiers in Nanophotonics |
30 May 2010 |
12 pages |
| Authors:
Alexander K Popov; WISCONSIN UNIV-STEVENS POINT
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| The possibilities of compensating losses in negative index metamaterials (NIMs) are shown without the requirements of population inversion. The approach relies on coherent nonlinear-optical energy transfer from the control optical field(s) to the NI signal through three- (TWM) and four-wave mixing (FWM) propagation processes. The feasibilities of tailoring the transparency of plasmonic slabs from strongly opaque through fully transparent to amplifying states with the control laser(s) as well as the ... |
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| All-Optically Transformable Broad-Band Transparency and Amplification in Negative-Index Films |
19 May 2010 |
4 pages |
| Authors:
Alexander K Popov; Sergey A Myslivets; WISCONSIN UNIV-STEVENS POINT DEPT OF PHYSICS AND ASTRONOMY
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| Negative-index metamaterials (NIMs) exhibit highly unusual optical properties and promise a great variety of unprecedented applications. However, strong optical absorption inherent to such materials imposes severe limitation on such applications. The possibility to overcome this obstacle was proposed based on the coherent energy transfer from the control field to the signal through three-wave mixing, which is accompanied by optical parametric amplification (OPA) in NIMs. It was shown that the transparency ... |
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| Complex Waves on 1D, 2D, and 3D Periodic Arrays of Lossy and Lossless Magnetodielectric Spheres |
16 MAY 2010 |
105 pages |
| Authors:
Robert A. Shore; Arthur D. Yaghjian; AIR FORCE RESEARCH LAB HANSCOM AFB MA ANTENNA TECHNOLOGY BRANCH
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| Complex waves propagating along the axes of 1D, 2D and 3D infinite periodic arrays of small lossless and lossy magnetodielectric spheres are investigated. The focus is on obtaining the kd-BETAd equations (diagrams) characterizing dipolar complex waves. The kd-BETAd (dispersion) equation for the complex propagation constants of a given array is obtained from the corresponding equation previously obtained for the real propagation constants by rewriting the real propagation dispersion equation in ... |
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| Coherent Distributed Radar for High-Resolution Through-Wall Imaging |
May 2010 |
4 pages |
| Authors:
van; Eric Doorn; Satya Ponnaluri; Xlangfeng Wang; INTELLIGENT AUTOMATION INC ROCKVILLE MD
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| We continued developing an overall plan for design of RF transceiver hardware for very accurate synchronization. Selection of key hardware components, such as a highly accurate reference clock has been narrowed down a few candidates. A meeting with the ONR client, and SAIC staff to kickoff the project was held. In this report we discuss progress in hardware design, synchronization algorithm, and definition of the final demonstration. In the previous ... |
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| Synthetic Aperture Radar Images of a Simple Room Based on Computer Models |
May 2010 |
62 pages |
| Authors:
Traian Dogaru; Calvin Le; Lam Nguyen; ARMY RESEARCH LAB ADELPHI MD SENSORS AND ELECTRON DEVICES DIRECTORATE
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| This report investigates the application of synthetic aperture radar (SAR) imaging techniques to sensing through the wall (STTW) scenarios based on radar data obtained through computer simulation of electromagnetic (EM) scattering problems using either the Finite Difference Time Domain (FDTD) method or Xpatch. We analyze the radar phenomenology for simple through-the-wall imaging scenarios and offer guidelines for a performance prediction and radar parameter trade-off. Our simulations show that, for these ... |
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| Application of the CLEAN Detector to Low Signal to Noise Ratio Targets |
May 2010 |
7 pages |
| Authors:
Terry L Foreman; NAVAL SURFACE WARFARE CENTER DAHLGREN VA ELECTROMAGNETIC AND SENSOR SYSTEMS DIV
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| This paper expands on the author's previous work by adapting the CLEAN algorithm to address low signal to noise (SNR) targets. The Reformulated CLEAN Detector is presented which is shown to allow the detection of low SNR targets in the presence of large targets. Performance results are presented that show how good performance can be attained by combining the correlator, CLEAN Deconvolver and Reformulated CLEAN Detector. |
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| Mitigation of Coupling in RF Tomography with Applications to Belowground Sensing |
May 2010 |
6 pages |
| Authors:
Lorenzo L Monte; Lee K Patton; Michael C Wicks; AIR FORCE RESEARCH LAB DAYTON OH
|
| In imaging applications based on RF Tomography coupling between transmitters and receivers is a principal technical challenge to be overcome. To mitigate the coupling, we propose to activate different transmitters simultaneously, and determine their respective current source distribution in order to create electric field nulls at desired points (e.g., the receivers). The current design problem must take into consideration physical and system constraints of the radiators. As such, the current ... |
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| Conjugate Gradient Parametric Adaptive Matched Filter |
May 2010 |
8 pages |
| Authors:
Chaoshu Jiang; Hongbin Li; Muralidhar Rangaswamy; AIR FORCE RESEARCH LAB HANSCOM AFB MA SENSORS DIRECTORATE
|
| The parametric adaptive matched filter (PAMF) detector for space-time adaptive processing (STAP) detection is re-examined in this paper. Originally, the PAMF detector was introduced by using a multichannel autoregressive (AR) parametric model for the disturbance signal in STAP detection. While the parametric approach brings in benefits such as significantly reduced training and computational requirements as compared with fully adaptive STAP detectors, the PAMF detector as a reduced-dimensional solution remains unclear. ... |
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| An Interpretation of Woodward's Ambiguity Function and Its Generalization |
May 2010 |
7 pages |
| Authors:
John E Gray; NAVAL SURFACE WARFARE CENTER DAHLGREN VA
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| We suggest a new interpretation of Woodward's ambiguity function as the expected value of an operator. The operator represents the physics of the interaction of the waveform with the object. This approach provides a new approach to understanding the return signal at the receiver and can reveal more detailed understanding of the underlying interactions within the return signal that are not usually brought out by standard signal processing techniques. |
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| A Probabilistic Model of the Radar Signal-to-Clutter and Noise Ratio for Weibull-Distributed Clutter |
May 2010 |
7 pages |
| Authors:
R W McMillan; Ira Kohlberg; ARMY SPACE AND MISSILE DEFENSE COMMAND REDSTONE ARSENAL AL
|
| We consider four effects relevant to the determination of the ratio of radar signal to clutter and noise. These effects are atmospheric turbulence, target fluctuations based on the Swerling models, zero-mean Gaussian background and receiver noise, and Weibull-distributed clutter. Radar return signal levels are affected by target fluctuations and atmospheric turbulence, characterized by target fluctuations according to the Swerling models and a lognormal distribution, respectively. Since these distributions are not ... |
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| Second-Harmonic Generation by Electromagnetic Waves at the Surface of a Semi-Infinite Metal |
May 2010 |
7 pages |
| Authors:
Frank Crowne; Christian Fazi; ARMY RESEARCH LAB ADELPHI MD SENSORS AND ELECTRON DEVICES DIRECTORATE
|
| Reference [1], which appears in the Proceedings of the RADAR'09 Conference at Bordeaux in October 2009, describes nonlinear currents generated by an electromagnetic wave incident on a metal surface. This paper supplements the results of [1] with a full calculation of the RCS per unit area for second harmonic generation. These results verify that the level of such emission from a metal surface is anomalously low. |
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| Tight Bounds on the Ergodic Capacity of Cooperative Analog Relaying with Adaptive Source Transmission Techniques |
May 2010 |
7 pages |
| Authors:
A Annamalai; Bhuvan Modi; Ramesh Palat; John Matyjas; PRAIRIE VIEW A AND M UNIV TX DEPT OF ELECTRICAL AND COMPUTER ENGINEERING
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| Tight bounds for the Shannon capacity of amplify-and-forward cooperative diversity networks are derived for three different adaptive source transmission policies in a myriad of fading environments: (1) constant power with optimal rate adaptation (ORA); (2) optimal joint power and rate adaptation (OPRA); and (3) fixed rate with truncated channel inversion (TCIFR). Our unified framework based on the moment-generating function (MFG) approach allows us to gain insights as to how fad ... |
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| Acoustic Holography with a Concentric Rigid and Open Spherical Microphone Array |
May 2010 |
5 pages |
| Authors:
Abhaya Parthy; Craig Jin; Andre van Schaik; SYDNEY UNIV (AUSTRALIA) SCHOOL OF ELECTRICAL AND INFORMATION ENGINEERING
|
| We present a new method and performance data related to volumetric acoustic intensity imaging using a spherical microphone array (SMA) that consists of a dual, concentric rigid and open SMA. The dual, concentric array was designed to improve the frequency range of a standard SMA. We apply standard techniques associated with interior spherical near-field acoustic holography (NAH) and, in particular, consider issues related to the optimal use of information from ... |
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| Demonstration and Validation of an Improved Airborne Electromagnetic System for UXO Detection and Mapping |
May 2010 |
60 pages |
| Authors:
ENVIRONMENTAL SECURITY TECHNOLOGY CERTIFICATION PROGRAM OFFICE (DOD) ARLINGTON VA
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| In September 2008, Battelle completed construction of a new airborne, time-domain electromagnetic system for mapping and detecting unexploded ordnance (UXO). This system was developed with corporate funds on the basis of successful evaluation of a prototype system under Environmental Security Technology Certification Program (ESTCP) Project 200101. This system has been developed to address shortcomings of magnetometer-based systems where the presence of basalt flows or other iron-bearing soils and rocks impede ... |
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| High Power, Pulsed, RF Generation from Nonlinear Lumped Element Transmission Lines (NLETLs) |
30 Apr 2010 |
263 pages |
| Authors:
Jamie Darling; Paul W Smith; OXFORD UNIV (UNITED KINGDOM) DEPT OF ENGINEERING SCIENCE
|
| This research project studies the generation of high power bursts of solitons/nonlinear oscillations at radio frequencies from nonlinear lumped element transmission lines (NLETLs) where the nonlinear elements are ferroelectric capacitors or metallised tiles of ferroelectric ceramic. This work leads on from an existing programme where nonlinear tuning diodes or varactors have been used in NLETLs to study and model these phenomena. Earlier work in our laboratories has already demonstrated the ... |
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| Evaluation of the LWVD Luminosity for Use in the Spectral-Based Volume Sensor Algorithms |
29 Apr 2010 |
30 pages |
| Authors:
Daniel A Steinhurst; Jeffrey C Owrutsky; NOVA RESEARCH INC ALEXANDRIA VA
|
| Prototype. An integrated sensor suite and local data fusion algorithms are being designed as the Volume Sensor Detection Suite (VSDS). As an example of potential inter-component data fusion for the VSDS, the Long Wavelength Video Detection (LWVD) Component Luminosity was investigated as a substitute for the near-infrared (NIR) sensor element in the Spectral-Based Volume Sensor (SBVS) component of the VSDS. The LWVD Luminosity data stream can be used to produce ... |
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| Globally Convergent Inverse Reconstruction Algorithm for Detection of IEDs via Imaging of Spatially Distributed Dielectric Constants using Microwave |
27 APR 2010 |
41 pages |
| Authors:
Michael V. Klibanov; Michael A. Fiddy; NORTH CAROLINA UNIV AT CHARLOTTE DEPT OF MATHEMATICS
|
| This grant was given for the period of nine months. The goal of this funding was to verify experimentally the ability of a quantifiable imaging of dielectrics by the new globally convergent inverse algorithm of the PI. The latter activity is supported by the ARO grant W911NF-08-1-0470. This funding was used as a leverage for the reported activity. The desired confirmation was achieved. It is of importance that BLIND imaging ... |
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| SQIF Array Dynamics |
20 Apr 2010 |
31 pages |
| Authors:
Stanford P Yukon; AIR FORCE RESEARCH LAB HANSCOM AFB MA SENSORS DIRECTORATE/ELECTROMAGNETICS TECHNOLOGY DIV
|
| An analytic perturbation solution is developed for a single cell SQUID and for multi-cell rows with random cell sizes (constrained by having a mirror symmetry about the center junction). The response of a single SQUID to an external RF signal is determined in terms of correlation functions between the phase of the inline effective junction and the circulating current. This yields an RF phase shift that can be calculated as ... |
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| Differential Frequency Hopping (DFH) Modulation for Underwater Acoustic Communications and Networking |
19 Apr 2010 |
11 pages |
| Authors:
Geoffrey S Edelson; Dianne E Egnor; BAE SYSTEMS NASHUA NH
|
| The primary technical objective of this effort is to realize theoretical DFH performance in the doubly spread underwater acoustic channel. To do so, we need to develop demodulation schemes that are robust to various aspects of the environment. Variations in water depth, bottom type, sound speed profile, and source/receiver location call provide for wide ranges of multi-path interference (resulting in time spread). Different wind and surface wave conditions in combination ... |
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| Fundamental Physics and Practical Applications of Electromagnetic Flow Control in High Speed Flows |
05 APR 2010 |
17 pages |
| Authors:
Graham V. Candler; MINNESOTA UNIV MINNEAPOLIS
|
| There are two overall objectives of the proposed research program. The first objective is to perform fundamental studies of microwave and combined microwave/laser energy deposition. The studies include characterization of the new microwave coaxial resonator at the University of Illinois, and development of kinetic-gasdynamic models for microwave and combined microwave/laser energy deposition in air. The second objective is to investigate practical applications of microwave and combined microwave/laser energy deposition for ... |
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| Results of Bare Die Probing for RF Booster Chip at 450, 915, and 2400 MHz |
Apr 2010 |
110 pages |
| Authors:
Gregory Mitchell; John Penn; ARMY RESEARCH LAB ADELPHI MD
|
| Low-power radio frequency (RF) transceivers have been used for low-cost, high volume commercial applications that do not always meet the needs of critical Army systems. In low-power applications, a tradeoff between transmit range and battery life exists. A simple means of extending transmit range would be to add a custom integrated circuit (IC) between the transceiver and antenna. Using appropriate technologies, a tradeoff in size, efficiency, and performance is achievable. ... |
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| Radio Frequency (RF) Propagation Along Single Cylindrical Conductors |
Apr 2010 |
10 pages |
| Authors:
D Clint Friedman; Harris Goldman; ARMY ARMAMENT RESEARCH DEVELOPMENT AND ENGINEERING CENTER PICATINNY ARSENAL NJ
|
| This report examines the transmission of 10 GHZ radio frequency (RP) waves among single cylindrical conductors. Intent is to determine attenuation as a function of distance and conductivity in order to enhance understanding of phenomena related to attachment and transmission of RF to a laser generated plasma filament(s). Attenuation is shown to be highly dependent on conductivity as well as diameter of conductor in some cases providing significant gain over ... |
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| Enhanced Photophysical Processes in Controlled Electromagnetic Nanoenvironments |
Apr 2010 |
13 pages |
| Authors:
Surbhi Lal; Naomi Halas; RICE UNIV HOUSTON TX DEPT OF ELECTRICAL AND COMPUTER ENGINEERING
|
| The objectives of this grant Enhanced Photophysical Processes in Controlled Nanoenvironments were to investigate the role of electromagnetic nanoenvironments on fundamental photophysical processes in molecular species. By systematically designing tunable plasmonic nanostructures such as nanoshell dimers, small clusters, extended monolayer arrays of nanoparticles, and other hybridized structures, controlled electromagnetic environments can be created. The enhanced fields generated in these environments is then used to study photophysical processes such as surface ... |
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| Coupled Ocean/Atmospheric Mesoscale Prediction System (COAMPS), Version 5.0 (User's Guide) |
30 Mar 2010 |
82 pages |
| Authors:
Travis A Smith; TImothy J Campbell; Richard A Allard; Suzanne N Carroll; NAVAL RESEARCH LAB STENNIS SPACE CENTER MS OCEANOGRAPHY DIV
|
| The Coupled Ocean/Atmospheric Mesoscale Prediction System (COAMPS) Version 5.0 is a fully coupled, data assimilative model which consists of both COAMPS Version 3 and the Navy Coastal Ocean Model (NCOM) Version 4. Coupling of the two models is accomplished via the Earth System Modeling Framework (ESMF) in which surface fluxes of momentum and moisture are exchanged across the air-sea interface. This version of the user's manual (1.0) includes instructions to ... |
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| Wavelet Spectral Finite Elements for Wave Propagation in Composite Plates with Damages |
24 Mar 2010 |
21 pages |
| Authors:
S Gopalakrishnan; INDIAN INST OF SCIENCE BANGALORE (INDIA)
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| For the Current Year (2009-2010), a new spectral plate element (SPE) for laminated composite using Daubechies compactly supported wavelet basis functions is developed to analyze wave propagation in an anisotropic laminated composite media. The element is based on the Classical Laminated Plate Theory (CLPT). The element is formulated using the recently developed methodology of spectral finite element formulation based on the solution of a Polynomial Eigenvalue Problem (PEP). By virtue ... |
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| Basic Studies in Microwave Sciences |
22 Mar 2010 |
11 pages |
| Authors:
Pingshan Wang; Chunrong Song; Hanqiao Zhang; Yongtao Geng; Huan Zou; CLEMSON UNIV SC
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| This project studies (i) DI water properties under high-electric field stress, and (ii) CMOS circuits to capture and analyze short electrical pulses. For the first task, microwave microfluidic channels are fabricated with 260 nm channel heights. DC voltages up to 38 V are applied to DI water with its dielectric permittivity measured up to 16 GHz. Significant water permittivity reduction is observed when the applied field is 1 MV/cm. A ... |
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| Scattering of Electromagnetic Waves in the Presence of Wave Turbulence Excited by a Flow with Velocity Shear |
19 Mar 2010 |
32 pages |
| Authors:
Vladimir Sotnikov; Jean-Noel Leboeuf; Saba Mudaliar; NEVADA UNIV RENO DEPT OF PHYSICS
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| It is well-known that an incompressible sheared flow with an inflection point in the velocity profile will result in the formation of turbulent vortices. In the case of compressible plasma flow with velocity shear ion acoustic fluctuations in addition to vortices will be generated. We present a detailed analysis of the excitation of such low frequency oscillations in a compressible plasma flow with velocity shear. To examine the process of ... |
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| Frequency Extension of the Negative Index Materials (FENIM) |
15 Mar 2010 |
8 pages |
| Authors:
Eleftherios N Economou; FORTH/IACM HERAKLION (GREECE)
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| This report results from a contract tasking Foundation for Research and Technology, Hellas (FORTH) as follows: The expected results include full understanding of the role of the periodicity on the negative index behavior. Exploitation of this understanding for optimization of Left Handed Materials (LHM) for different functionalities. (b) Negative Index Materials (NIM) operating in the THz regime and upwards. Determination of the frequency limits of the NIM behavior and understanding ... |
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Radiofrequency Wave Propagation
