| Nanomagnet Arrays for Patterned Magnetic Media and Magnonic Crystal Applications |
31-Aug-2009 |
11 pages |
| Authors:
Manish Sharma; INDIAN INST OF TECH NEW DELHI
|
 | In this project, we have fabricated arrays of nanomagnets and characterized them for use as patterned media for high-density magnetic storage and as magnonic crystals in the microwave range. The nanomagnet arrays have been formed by electrodeposition in templates with feature sizes in the sub-100nm range using an electrodeposition system bought as part of this project. We have modelled the dynamic switching of the magnetizations in these arrays, and also ... |
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| Control and Optimization of Coherence of a Nano-Sized Spin-Torque Microwave Oscillator for Military Nano-Electronics |
30-Nov-2008 |
27 pages |
| Authors:
G Gerhart; E Bankowski; V S Tiberkevich; A N Slavin; ARMY RESEARCH DEVELOPMENT AND ENGINEERING COMMAND WARREN MI
|
| Passage of an electric current through a multilayered magnetic nano structure can lead to the excitation of a persistent magnetization precession in the thinner (free) magnetic layer of the structure. The frequency of the excited auto oscillations is close to the ferromagnetic resonance frequency and typically lies in the microwave frequency range. This effect can be used for the development of a novel class of fully metallic microwave nano sized ... |
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| Demonstration and Modeling of Material Responses Achieved Through Contradirectional Coupling |
14 MAY 2008 |
19 pages |
| Authors:
Anthony Grbic; MICHIGAN UNIV ANN ARBOR DEPT OF ELECTRICAL ENGINEERING AND COMPUTER SCIENCE
|
| This report describes the development of broadband and reduced-loss negative permeability and negative refractive index metamaterials at microwave frequencies. The reported structures exhibit fractional bandwidths that are greater than 40%. Simulation and experimental results are described which confirm the electromagnetic properties of the proposed structures. Analytical modeling of the proposed structures is also discussed. |
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| Quantum Computation with Superconducting Quantum Devices |
14 APR 2008 |
17 pages |
| Authors:
Terry P. Orlando; MASSACHUSETTS INST OF TECH CAMBRIDGE RESEARCH LAB OF ELECTRONICS
|
| This project has experimentally characterized the coherent quantum nature of the superconducting persistent current qubits which were fabricated in the trilayer niobium technology. The quantum levels of these qubits have been mapped out using both standard microwave frequency spectroscopy as well as a new technique of amplitude spectroscopy. Important to the future implementation of these qubits for quantum computing applications is the demonstration of microwave sideband cooling of the qubits ... |
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| Interchannel Crosstalk Reduction in an Analog Fiber Link Using Dispersion Management |
15 FEB 2008 |
4 pages |
| Authors:
Brian S. Marks; Curtis R. Menyuk; Anthony L. Campillo; Frank Bucholtz; MARYLAND UNIV BALTIMORE
|
| It has previously been shown that dispersion compensation can dramatically affect the interchannel crosstalk in a multichannel analog fiber transmission link. In this work, we use a genetic algorithm to find five-segment dispersion maps that yield low crosstalk levels over two octaves of microwave-frequency bandwidth when amplitude modulation is used. The genetic algorithm suggests that optimal dispersion maps have low residual dispersion. Despite the genetic algorithm's ability to optimize dispersion ... |
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| Numerical Modeling of the Airborne Radar Signature of Dismount Personnel in the UHF-, L-, Ku-, and Ka-Bands |
DEC 2007 |
30 pages |
| Authors:
Calvin Le; Traian Dogaru; ARMY RESEARCH LAB ADELPHI MD SENSORS AND ELECTRON DEVICES DIRECTORATE
|
| This technical report presents numeric computations of the radar cross section (RCS) of a human body placed on top of a ground plane, as seen by an airborne radar. The simulated data was collected in four frequency bands, at low microwave frequencies (UHF- and L-bands), and high microwave frequencies (Ku- and Ka-bands). For the low frequency bands we used the Finite Difference Time Domain (FDTD) modeling technique, whereas for the ... |
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| Angular Dependence of the Microwave-Generation Threshold in a Nanoscale Spin-Torque Oscillator |
20-Jul-2007 |
5 pages |
| Authors:
G Gerhart; E Bankowski; G A Melkov; V S Tiberkevich; A N Slavin; ARMY TANK-AUTOMOTIVE RESEARCH AND DEVELOPMENT COMMAND WARREN MI
|
| It is shown that in a spin-torque microwave oscillator based on a magnetic nanocontact, the nature of the microwave spin wave mode generated at the threshold critically depends on the angle between the external bias magnetic field and the plane of the free layer. When the external bias field is rotating from normal to in-plane orientation, an abrupt transition from a propagating cylindrical wave with the frequency higher than the ... |
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| Analysis of an Optical Channelization Technique for Microwave Applications |
27 JUN 2007 |
20 pages |
| Authors:
Matthew S. Rogge; Vincent J. Urick; Frank Bucholtz; NAVAL RESEARCH LAB WASHINGTON DC OPTICAL SCIENCES DIV
|
| Increasing electrical bandwidth combined with improved optical filtering allow for a new class of optical channelizers for use in radiofrequency, microwave, and millimeter-wave applications. After a brief review of existing channelization technology, an optical channelizer that uses optical local oscillators and optical filters is analyzed. Linearity and other limitations of the scheme show a strong dependence on the linearity of the optical modulator. The optical modulator is explored in both ... |
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| Study of Properties of the Microwave Streamer Discharge in a High-Speed Flow of Gas and in Two-Phase Medium |
01 AUG 2006 |
102 pages |
| Authors:
Kirill V. Khodataev; FEDERAL STATE UNITARY FIRM MOSCOW RADIO-TECHNICAL INST (RUSSIA)
|
| This report results from a contract tasking Federal State Unitary Firm 'MRTI' of RAS as follows: The contractor will investigate the use of undercritical streamer microwave discharges for ignition of fuel-air mixtures. The system of microwave radiation initiated spark filaments can uniformly fill a volume with streamers of several thousand degrees Kelvin. Thus, quick ignition of fuel-air mixtures over the whole cross-section of the discharge is anticipated. Experimental and theoretical ... |
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| Electronic Properties and Device Applications of III-V Compound Semiconductor Native Oxides |
02 MAR 2006 |
67 pages |
| Authors:
Douglas C. Hall; Patrick J. Fay; Thomas H. Kosel; Bruce A. Bunker; Russell D. Dupuis; NOTRE DAME UNIV IN DEPT OF ELECTRICAL ENGINEERING
|
| Notre Dame has demonstrated the first gallium arsenide (GaAs)-based metal-oxide-semiconductor field-effect-transistor (MOSFET) utilizing a native oxide gate dielectric which has excellent microwave frequency performance and, due to its low gate leakage, promises both low-power operation and potential for superior power amplifier devices. We have shown that the wet-thermal native oxides of the compound semiconductor indium aluminum phosphide (InAlP) can be scaled to thicknesses required for devices (10- 20 nm) and ... |
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| A Novel Superconducting Device to Isolate, Entangle and Read Out Flux Qubits |
21 FEB 2006 |
17 pages |
| Authors:
John Clarke; CALIFORNIA UNIV BERKELEY SPONSORED PROJECTS OFFICE
|
| Experiments are described in which the quantum states of two flux qubits were read out by a dc SQUID (Superconducting QUantum Interference Device). Observations of the linewidths of microwave-induced peaks. Ramsey fringes and flux echoes on a single qubit yielded values of the decoherence times T(sub 2)', T(sub 2)* and T(sub 2). respectively. Within the experimental errors, the values satisfied the prediction 1/T(sub 2)* =1/T(sub 2)' + 1/T(sub 2). Spectroscopic ... |
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| Hurricane Wind Vector Estimates from WindSat Polarimetric Radiometer |
25 JUL 2005 |
5 pages |
| Authors:
Ian S. Adams; Christopther C. Hennon; W. L. Jones; Khalil Ahmad; MICROWAVE REMOTE SENSING CONSULTANTS COCOA BEACH FL
|
| WindSat is the world's first microwave polarimetric radiometer, designed to measure ocean vector winds. In late 2004, the first preliminary oceanic wind vector results were released, and this paper presents the first evaluation of this product for several Atlantic hurricanes during the 2003 season. Both wind speed and wind direction comparisons will be made with surface wind analysis (H*Wind) developed by the NOAA Hurricane Research Division (HRD) and provided by ... |
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| Low Phase Noise Fiber Optics Links for Space Applications |
13 JUL 2005 |
9 pages |
| Authors:
Bertrand Onillon; Stephanie Constant; Gianandrea Quardi; Benoit Benazet; Olivier Llopis; CENTRE NATIONAL DE LA RECHERCHE SCIENTIFIQUE TOULOUSE (FRANCE) LAB DE METALLURGIE PHYSIQUE
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| This paper summarises the results obtained on different systems dedicated to the optical distribution of high spectral purity RF and microwave signals in a satellite payload or towards the elements of an active antenna. First, the interest of the photo-oscillator receiver for these applications in the RF frequency range is pointed out. Then, different emitter configurations are investigated in the microwave range . Finally, an application of these low phase ... |
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| Technology Disruptions in Future Communication Payloads (Technologies de rupture pour futures charges utiles de telecommunications) |
13 JUL 2005 |
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| Authors:
Jean-Didier Gayrard; ALCATEL SPACE TOULOUSE (FRANCE)
|
 | The future market of satellite telecommunications will be shaped by four main trends: democratization, regionalization, digitalization, and the use of higher frequency bands. To cope with the economic and technical demands of the market and to compete with terrestrial networks, operators and manufacturers will need to upgrade their satellites. The evolution of satellite communications could go one of three ways: gigantism, adaptation, or modularity. Any of these ways will require ... |
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| Fabrication of Organic Radar Absorbing Materials: A Report on the TIF Project |
MAY 2005 |
|
| Authors:
Paul Saville; Trisha Huber; Darren Makeiff; DEFENCE RESEARCH AND DEVELOPMENT ATLANTIC DARTMOUTH (CANADA)
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| The fabrication of microwave absorbing materials requires the ability to make materials with well-controlled properties such as shape, thickness, permittivity and permeability. The ability to measure the permittivity and permeability is an essential requirement for designing an optimised absorber. And good optimisations codes are required in order to achieve the best possible absorber designs. In this report, the results from a Technology Investment Funded project on the fabrication of organic ... |
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| Finite Difference Time Domain (FDTD) Analysis of a Leaky Traveling Wave Microstrip Antenna |
21 MAR 2005 |
158 pages |
| Authors:
Gregory M. Zelinski; AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH DEPT OF ELECTRICAL AND COMPUTER ENGINEERING
|
| This thesis provides the groundwork that will enable the development of a lightweight, inexpensive, aerodynamic, and broadband antenna. Whether for radar or communication, an antenna with these properties would be a force multiplier for the smaller, limited payload air vehicles the United States Air Force will pursue in the coming years. Several microstrip antennas using the first higher order mode were simulated with the Finite-Difference Time-Domain (FDTD) method. The propagation ... |
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| Characterization of Meta-Materials Using Computational Electromagnetic Methods |
JAN 2005 |
5 pages |
| Authors:
Manohar Deshpande; Joon Shin; NATIONAL AERONAUTICS AND SPACE ADMINISTRATION HAMPTON VA LANGLEY RESEARCH CENTER
|
| An efficient and powerful computational method is presented to characterize a meta-material in terms of its specified electromagnetic properties. Using the periodicity of meta-materials, the Finite Element Methodology (FEM) is developed to estimate reflection and transmission through the meta-material structure for a normal plane wave incidence. For efficient computations of reflection and transmission through a meta-material over a wideband frequency range, a Finite Difference Time Domain (FDTD) approach is developed. ... |
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| Single-Receptor Interfaces for Real-Time Kinetics |
2005 |
9 pages |
| Authors:
Daniel van der Weide; Robert Blick; WISCONSIN UNIV-MADISON DEPT OF ELECTRICAL AND COMPUTER ENGINEERING
|
| The purpose of this research is to develop a label-free, field- deployable electronic interface to membrane proteins used as biosensing elements. We developed and demonstrated a new method for single-molecule electrophysiology, measuring changes in microwave-frequency transmission through a pore in a planar lipid bilayer simultaneously with conventional single-channel DC recordings. The results indicated that an increase in capacitance of order 0. 5-1 fF was observed with blocking of the pore. ... |
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| Multifrequency Retrieval of Cloud Ice Particle Size Distributions |
2005 |
87 pages |
| Authors:
Brian D. Griffith; COLORADO STATE UNIV FORT COLLINS DEPT OF ATMOSPHERIC SCIENCE
|
| There are many sources of uncertainty in remote sensing retrievals. This is particularly true where complex parameters such as liquid or ice hydrometeors must be retrieved. Many of the uncertainties are the direct result of assumptions made in the retrieval process to address the ill-posed nature of the inverse problem namely that there are more variables than measurements. In this paper, an optimal estimation retrieval technique is applied to a ... |
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| Wideband Electroabsorption Modulator for Microwave Photonics |
OCT 2004 |
15 pages |
| Authors:
P. K. Yu; Wu ; Y. Zhuang; J. Fischer; A. R. Clawson; CALIFORNIA UNIV REGENTS SAN DIEGO LA JOLLA CA
|
| The technical objective/approach of this effort was to design and test a novel material and electrode structure of traveling wave electroabsorption modulators (TWEAMs) for use in microwave transmission systems exceeding frequencies of 50 GHz. Potential monolithic integration of these modulators with low noise lasers is promising for insertion into future space- based and air borne platforms in which physical size is a primary concern. This report details the University of ... |
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| Ba1xSrxTiO3 Based Thin Films for Next Generation Devices |
SEP 2004 |
14 pages |
| Authors:
Eric Ngo; William d. Nothwang; Clifford Hubbard; Samuel Hirsch; Melaine W. Cole; ARMY RESEARCH LAB ABERDEEN PROVING GROUND MD WEAPONS AND MATERIALS RESEARCH DIRECTORATE
|
| Over the past several years. there has been a tremendous growth and development of thin film deposition technology in the electronics industry. Ferroelectric thin films have been recognized for their unique dielectric properties and appear to be desirable for tunable microwave device applications. Among the most promising candidates for such applications are Ba(1-x)Sr(x)TiO(3) (BST) and BST-based thin films. In this work, pure BST and acceptor doped BST- based thin films ... |
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| A New Cyclotron Maser Mechanism Observations and Theory |
07 APR 2004 |
1 pages |
| Authors:
R. Bingham; A. Cairns; A. D. Phelps; STRATHCLYDE UNIV GLASGOW (UNITED KINGDOM)
|
| We present a new cyclotron maser type instability driven by a crescent or horseshaped electron distribution function. Such distribution functions are easily created by an electron beam moving into a stronger magnetic field region, where conservation of the first adiabatic invariant causes an increase in their pitch angle. This produces a broad region on the distribution function where there is a +ve slope in the perpendicular component of the velocity ... |
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| Thin Film Encapsulation of Radio Frequency (RF) Microelectromechanical Systems (MEMS) Switches |
MAR 2004 |
166 pages |
| Authors:
Eric D. Marsh; AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH SCHOOL OF ENGINEERING AND MANAGEMENT
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| Microelectromechanical systems (MEMS) radio frequency (RF) switches have been shown to have excellent electrical performance over a wide range of frequencies. However, cost-effective packaging techniques for MEMS switches do not currently exist. This thesis involves the design of RF-optimized encapsulations consisting of dielectric and metal layers, and the creation of a novel thin film encapsulation process to fabricate the encapsulations. The RF performance of several encapsulation designs are evaluated with ... |
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| Microwave Doppler Measurements of Projectile Velocity in a Single-Stage Gas Gun |
JAN 2004 |
14 pages |
| Authors:
J. Justiss; S. Levinson; R. Russell; TEXAS UNIV AT AUSTIN INST FOR ADVANCED TECHNOLOGY
|
| A microwave-frequency Doppler system was developed and implemented in a single-stage gas gun to develop an in-bore velocity profile. The technique uses a 24.15 GHz microwave transceiver to measure the Doppler frequency change as the projectile travels down the bore. The difference of the source signal and the shifted signal was digitally extracted by a mixer and recorded by a digital oscilloscope. From each recorded signal, the Doppler frequency shift ... |
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| An Electromagnetic/Acoustic Propagation Experiment |
NOV 2003 |
13 pages |
| Authors:
H. T. Banks; NORTH CAROLINA STATE UNIV AT RALEIGH CENTER FOR RESEARCH IN SCIENTIFIC COMPUTATION
|
| We proposed experiments to investigate electromagnetic acoustic waves interaction as part of a technology for pulsed microwave interrogation of materials. The technology involves using reflections of electromagnetic pulses from moving acoustic wavefronts to detect the presence of and determine composition (dielectric and geometric) of hidden objects. Applications of interest to DoD involve non-invasive interrogation of tissue, look-down surveillance and camouflage penetration (e.g., tanks under trees, and subsurface mines and bunkers) ... |
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| Exploitation of Omnidirectional Reflectivity |
SEP 2003 |
27 pages |
| Authors:
Tri Van; Dennis Nyquist; Leo Kempel; Gang Bao; MISSION RESEARCH CORP SANTA BARBARA CA
|
| In this final report, we have summarized the progress made during the period of September 1. 2002-September 30, 2003. We derive the integral equations for (electric fields propagating in a fiber of arbitrary cross section and arbitrary refractive index. Mathematical analysis of conventional optical fibers is rich and widely available in literature, for example 3, 9, 11 and references therein. It helps the advancement of optical fiber industry in understanding ... |
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| Signal Detection Theory-Based Information Processing for the Detection of Breast Cancer at Microwave Frequencies |
AUG 2003 |
49 pages |
| Authors:
Loren W. Nolte; DUKE UNIV DURHAM NC
|
| This research addressed directly the decision-theoretic task of detection and localization of breast tumor, using microwave diffraction measurements. Microwave energy has the advantages that at low power levels there are no radiation dangers, no contrast agents, and the examinations are comfortable. Although there is considerable scattering of a microwave signal in tissue, the presence, location, and nature of tumors is "coded" in the combination of amplitude and phases in the ... |
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| High Resolution Transferred Substrate HBT Microwave/RF ADCs |
21 APR 2003 |
21 pages |
| Authors:
Mark J. Rodwell; CALIFORNIA UNIV SANTA BARBARA DEPT OF ELECTRICAL AND COMPUTER ENGINEERING
|
| The attached report describes development of wideband delta sigma ADOs using high speed Indium Phosphide bipolar transistors. |
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| Sub 0.1 Micrometer Asymmetric Gamma-Gate PHEMT Process Using Electron Beam Lithography |
03 APR 2003 |
|
| Authors:
W. S. Sul; D. H. Shin; J. K. Rhee; DONGGUK UNIV SEOUL (REPUBLIC OF KOREA)MILLIMETER-WAVE INNOVATION TECHNOLOGYRESEARCH CENTER
|
| In this paper, we have studied on the fabrication of GaAs-based pseudomorphic high electron mobility transistors (PHEMT's) for the purpose of millimeter-wave applications. To fabricate the high performance GaAs-based PHEMT's, we have developed unit processes, such as 0.1 micrometer GAMMA-gate lithography, silicon nitride passivation, and air-bridge process to achieve high performance of device characteristics. The DC characteristics of the fabricated PHEMT was measured at a unit gate width of 70 ... |
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| Optics Microwave Interactions (Interactions entre optique et micro- ondes) |
APR 2003 |
|
| Authors:
NATO RESEARCH AND TECHNOLOGY ORGANIZATION NEUILLY-SUR-SEINE (FRANCE)
|
| The field of optics-microwave covered by this 2 day lecture series can generally be defined as the study of high speed devices and systems operating at microwave, millimeterwave and even THz frequencies. The benefits drawn by the introduction of optics in microwave techniques are illustrated through numerous examples. This two-day lecture series covers the main applications of optomicrowaves to the defence area through a broad approach going from devices to ... |
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| Computer Simulations of Microwave Generation from Relativistic Electron Beams |
15 MAR 2003 |
17 pages |
| Authors:
Anthony T. Lin; CALIFORNIA UNIV LOS ANGELES DEPT OF PHYSICS
|
| This is the Final Technical Report on work performed under the support of the Air Force Office of Scientific Research on the subject of simulating microwave generation. This report contains the write-ups that we sent for the upcoming book on power vacuum electronics. The first section (Chapter 10) describes the simulation algorithm based on mode expansion technique developed at UCLA while the second section (Chapter 5) gives the real amplification ... |
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| Imaging of Early-Stage Breast Cancers Using Pulsed Confocal Microwave Technology |
MAY 2002 |
46 pages |
| Authors:
Milica Popovic; Allen Taflove; NORTHWESTERN UNIV EVANSTON IL
|
| The work presented in this report is motivated by the need to calibrate a new pulsed-microwave breast tumor detection system for patient- specific skin parameters. A two-dimensional time-domain inverse-scattering algorithm based upon the finite-difference time-domain method is presented for determining the skin thickness and the relative permittivity and electric conductivity of skin in the microwave range. The algorithm traces a search trajectory in the two-dimensional parameter space. The minimal parameter ... |
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| A Static Technique for the Electro-Mechanical Characterization of Organic MEMS Devices for RF and Microwave Applications |
MAR 2002 |
10 pages |
| Authors:
Anupama B. Kaul; Tomasz Klosowiak; Joshua Liu; MOTOROLA LABS SCHAUMBURG IL ADVANCED TECHNOLOGY CENTER
|
| An approach for measuring force-dependent properties of microscopic structures commonly found in MEMS has been developed. The system has the capability of measuring forces and deflections on the order of micro-newtons and micro-meters, respectively. By implementing a visual inspection system, force can be selectively applied to localized areas on a beam, and the resulting force-deflection characteristic obtained from which beam stiffness and effective elastic modulus can be calculated. These results ... |
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| Polarimetric Emission Model of the Sea at Microwave Frequencies and Comparison with Measurements |
2002 |
31 pages |
| Authors:
K. St. Germain; G. A. Poe; P. W. Gaiser; NAVAL RESEARCH LAB WASHINGTON DC
|
| At two-scale scattering model of the sea developed in terms of wind-generated stochastic processes of the surface-the elevation spectral density of the small-scale structure and the probability density of slopes of the large scale roughness-is combined with the Durden/Vesecky [1] wave height spectral model to analyze recent polarimetric measurements. Ad hoc parameter values are found for the wave model that allow the two-scale model to account for essentially all of ... |
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| Center for Computational Electromagnetics of Complex Structures |
31 DEC 2001 |
14 pages |
| Authors:
Weng C. Chew; ILLINOIS UNIV AT URBANA DEPT OF ELECTRICAL AND COMPUTER ENGINEERING
|
| On the frequency domain fast solvers front, we have: We have continued our focus on improving the Fast Illinois Solve Code (FISC) which has a user base of over 400 distributed by SAIC/DEMACO. To stress the code for large scale computing, we put FISC through a number of tour de force computations. Recently, we have put FISC through a broad bandwidth calculation where we can simulate the time-domain scattering from ... |
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| Silicon-on-Sapphire Technology: A Competitive Alternative for RF Systems |
AUG 2001 |
6 pages |
| Authors:
Isaac Lagnado; Paul R. de la Houssaye; S. J. Koester; R. Hammond; J. O. Chu; J. A. Ott; P. M. Mooney; L. Perraud; K. A. Jenkins; SPACE AND NAVAL WARFARE SYSTEMS CENTER SAN DIEGO CA
|
| The authors investigated the formation of high-performance, device- quality, thin-film silicon (30 to 50 nm) on sapphire (TFSOS) for application to millimeter-wave communication and sensors. The resulting TFSOS, obtained by Solid Phase Epitaxy (SPE), and the growth of strained silicon-germanium (SiGe) layers on these TFSOS demonstrated enhanced devices and integrated circuit performance not achieved previously. The authors fabricated 250-nm and 100-nm T- gated devices with noise figures as low as ... |
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| Three-Dimensional Synthetic Aperture Radar for Mine Detection and Other Uses |
08 JUN 2001 |
17 pages |
| Authors:
John A. Pavco; DEPARTMENT OF THE NAVY WASHINGTON DC
|
| A radar system for generating a three-dimensional image includes a radar transmitter which is operable to produce a radar signal of a frequency of at least three gigahertz. A plurality of radar receiving antennas from an antenna array. The antenna array is aerially translatable. For example, in one embodiment, the antenna array is disposed along the wings of an aircraft which, in operation, flies over the intended target area. A ... |
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| Parametric Study of Propagation in Evaporation Ducting and Subrefractive Conditions |
NOV 2000 |
40 pages |
| Authors:
R. A. Paulus; SPACE AND NAVAL WARFARE SYSTEMS CENTER SAN DIEGO CA
|
| This report quantifies propagation loss differences that result from approximating the full stability-dependent refractivity profiles with neutral- stability profiles parameterized by duct height. It also develops a parameterization for subrefractive profiles and quantifies the propagation loss differences that result from approximating the full stability-dependent refractivity profiles with neutral-stability profiles parameterized by subrefractive layer height. |
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| Low-Noise WideBand Heterodyne Optical Array Receiver |
10 OCT 2000 |
19 pages |
| Authors:
Vinson L. Go; DEPARTMENT OF THE NAVY WASHINGTON DC
|
| A system and method is disclosed for detecting optical signals that is especially suitable for use with a fiber optic sonar transducer array. The system preferably uses two photodiodes with a frequency response matched to within one percent over a bandwidth of at least one Gigahertz to reduce common mode intensity noise. Preferably the two photodiodes are manufactured on the same semiconductor wafer to provide as closely identical properties as ... |
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| Space-Based Applications of Far-Infrared Systems |
29 SEP 2000 |
4 pages |
| Authors:
Michael C. Gaidis; JET PROPULSION LAB PASADENA CA
|
| This paper discusses the applications of space-based far-infrared/terahertz sensors and systems. It also covers the needs and desires of scientists, discusses what has been done to date, and what is planned for the future. |
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| Fast Physical Optics Simulation of the Dual-Reflector Submillimetre-Wave Telescope on the ESA PLANCK Surveyor |
29 SEP 2000 |
4 pages |
| Authors:
Vladimir Yurchenko; John A. Murphy; Jean-Michel Lamarre; AKADEMIYA NAUK URSR KHARKOV INST OF RADIOPHYSICS AND ELECTRONICS
|
| We present physical optics simulations of the dual-reflector submillimetre-wave telescope on the ESA PLANCK surveyor. The telescope is of a non-conventional Gregorian configuration, with two ellipsoidal reflectors providing a very large field of view at the focal plane where the array of 76 horn antennas feeding low-temperature detectors is located. We analyze defocusing effects of the system, polarization characteristics of the telescope, and the optical performance of high-frequency channels based ... |
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| An InGaAs/InAlAs Superlattice Oscillator for Frequencies Above 100 GHz |
29 SEP 2000 |
3 pages |
| Authors:
R. Scheuerer; E. Schomburg; A. Ignatov; K. F. Renk; D. G. Pavelev; INSTITUTE FOR RADIOPHYSICS NIZHNY NOVGOROD (RUSSIA)
|
| We present an InGaAs/InAlAs superlattice oscillator at 150 GHz with a superlattice device mounted in a waveguide and biased at a voltage of 1.3 V (current 15 mA), radiation of a power of 0.1 mW was generated. In the doped superlattice, the electron motion is governed by miniband transport, leading to a negative differential conductance due to Bragg reflection of the electrons at the miniband boundary. As a consequence, propagating ... |
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| Temperature Dependence of Low Energy Carrier Dynamics of Silicon by Terahertz Time Domain Spectroscopy |
29 SEP 2000 |
4 pages |
| Authors:
Shigeki Nashima; Osamu Morikawa; Kazue Takata; Masanori Hangyo; OSAKA UNIV (JAPAN) RESEARCH CENTER FORSUPERCONDUCTOR PHOTONICS
|
| The complex conductivity of moderately P-doped silicon wafers (1.1 plus or minus 0.2 ohm cm) at various temperatures has been deduced by using a terahertz time-domain (THz-TDS) spectroscopy. The characteristic dispersion of the complex conductivity is observed in the THz region. Temperature dependence of the complex conductivity changes dramatically around ^120 K, which is interpreted in terms of enhancement of mobility and the freezing of the carrier. The experimental data ... |
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| Use of RF Bias in LAPPS (Large Area Plasma Processing System) |
19 JUN 2000 |
20 pages |
| Authors:
Wallace M. Manheimer; Martin Lampe; Richard F. Fernsler; NAVAL RESEARCH LAB WASHINGTON DC FUNDAMENTAL PLASMA PROCESSES
|
| In the LAPPS processing scheme, RF bias can be used for either of two purposes: to provide energetic ion bombardment of a substrate, or to controllably raise the electron temperature (which is intrinsically very cool) to the desired value. The physics of RF bias in LAPPS differs from the situation in conventional processing reactors, for several reasons: (1) The plasma density adjacent to the substrate can be so ... |
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| Photoluminescence of InAs(1-x)Sb(x)/AlSb Single Quantum Wells: Transition from Type-II to Type-I Band Alignment |
01 JUN 2000 |
|
| Authors:
M. J. Yang; B. R. Bennett; M. Fatemi; P. J. Lin-Chung; W. J. Moore; C. H. Yang; NAVAL RESEARCH LAB WASHINGTON DC
|
| Infrared photoluminescence has been used to study the band-gap energy of InAs(1-x)Sb(x) digital superlattices and the band alignment of InAs(1-x)Sb(x)/AlSb quantum wells at 5 K. It is found that the InAs(1-x)Sb(x) digital alloys have a smaller effective band gap than InAs(1-x)Sb(x) random alloys. In addition, the valence band offset between type-II InAs/AlSb is determined to be 130 meV. This number reduces as the Sb mole fraction in InAs(1-x)Sb(x) is increased, ... |
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| Surface Current Determination from Localized Measurements |
29 FEB 2000 |
134 pages |
| Authors:
Morris P. Kesler; Jim Maloney; Paul Harms; Stephen Blalock; Eric Kuster; GEORGIA TECH RESEARCH INST ATLANTA
|
| This report describes the results of a research program aimed at developing and demonstrating a technique for determining surface currents from a series of electromagnetic field measurements. Two back-propagation techniques were developed and validated through numerical simulations and measurements on laboratory-scale, conducting objects. The first technique is a planar spectral decomposition approach that utilizes magnetic field measurements on a plane in front of the body, ... |
|
| Development of GaN Based Microwave Power Amplifier for X Band Applications |
20 JAN 2000 |
14 pages |
| Authors:
Kevin W. Alt; Kang L. Wang; PROCOMM ENTERPRISES INC SANTA MONICA CA
|
| The feasibility of utilizing the GaN/AlGaN material system in the development of high power amplifiers for X-band frequencies and above was investigated. The GaN based heterojunction field effect transistor (HFET) on SiC shows remarkable power density at microwave frequencies. An order of magnitude improvement can be attained in output power when compared with present GaAs devices, judging from the already observed power density along with further ... |
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| Polymer-Based Photonic Phased-Array Antenna System Based on Detector- Switched Optical Blass Matrix True-Time Delay Steering |
2000 |
14 pages |
| Authors:
Ray T. Chen; Bing Li; Yihong Chen; W. Steier; L. Dalton; TEXAS UNIV AT AUSTIN
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| This paper reports progress on the substrate guided wave optical true-time delay technique for photonic phase array antenna. Presented is a new optical TTD module design, and the work for PAA system demo. Like other photonic PAA technique, our structure can provide ultra-wide instantaneous bandwidth for PAA, without beam squint, which means when you change microwave frequency, the steering angle will not change. In addition, the ... |
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| SAGNAC Interferometer Amplitude Modulator Based Demultiplexer |
07 DEC 1999 |
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| Authors:
Michael L. Dennis; Irl N. Duling III; William K. Burns; DEPARTMENT OF THE NAVY WASHINGTON DC
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| This invention is a demultiplexer consisting on a sequential division of the data stream in a series of Sagnac interferometer amplitude modulators (SIAMs), wherein each modulator in the series is driven by a single microwave frequency derived directly from a radio frequency (RF) data rate clock, with the RF phase properly adjusted to extract a channel of interest. |
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| Rough Surface Propagation Effects at Wallops Island, February-April 1994 |
DEC 1999 |
30 pages |
| Authors:
H. V. Hitney; T. Nguyen; W. D. Thornton; SPACE AND NAVAL WARFARE SYSTEMS COMMANDSAN DIEGO CA
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| An unresolved radio propagation modeling problem is the effect of a wind-roughened sea surface on propagation at microwave frequencies in the evaporation duct. The biggest deficiency is the lack of suitable experimental data to validate various existing models. In 1994, the Naval Surface Warfare Center Dahlgren Division (NSWCDD) performed a radio propagation and meteorological measurement program at Wallops Island, Virginia, based on their ... |
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