U.S. flag

An official website of the United States government

Official websites use .gov
A .gov website belongs to an official government organization in the United States.

Secure .gov websites use HTTPS
A lock ( ) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.

Electronics

Electromagnetics

Search Publications

Search Title, Abstract, Conference, Citation, Keyword or Author
  • Published Date
Displaying 576 - 600 of 1580

Reversible axial-strain effect in Y-Ba-Cu-O coated conductors

November 7, 2005
Author(s)
Najib Cheggour, John (Jack) W. Ekin, C. L. H. Thieme, Y Y. Xie, V Selvamanickam, Ron Feenstra
The recently discovered reversible strain effect in Y-Ba-Cu-O (YBCO) coated conductors contrasts with the general understanding that the effect of strain on critical-current density J c in practical high-temperature superconductors is determined only by

Analyzing Carbon Fiber Composite Materials with Equivalent Layer

November 1, 2005
Author(s)
Christopher L. Holloway, M. S. Sarto, Martin Johansson
The purpose of this paper is toinvestigate the use of effective layer models for the analysis of carbon fiber composite materials. In this paper, we present three different models for the electromagnetic characterization (effective material properties) of

Realization of a Controllable Metafilm (''Smart Surface'') Composed of Resonant Magnetodielectric Particles: Measurements and Theory

November 1, 2005
Author(s)
Christopher L. Holloway, Pavel Kabos, Mohamed Mohamed, Edward Kuester, Michael D. Janezic, James R. Baker-Jarvis
In previous work, we derived generalized sheet-transition conditions (GSTCs) for the average electromagnetic fields across a metafilm, which, when properly designed, can have certain desired reflection and transmission properties. A metafilm is the two

Comparison of Gains Determined from the Extrapolation and Pattern Integration Methods

October 30, 2005
Author(s)
Michael H. Francis, Katherine MacReynolds, Jeffrey R. Guerrieri
Scientists at the National Institute of Standards (NIST) have measured the gain of several antennas using two different methods. The first method is the three-antenna extrapolation method developed at NIST in the early 1970s. The second method is the

Planar Near-Field Measurements Results up to 94 GHz Using Probe Position Correction

October 30, 2005
Author(s)
Jeffrey R. Guerrieri, Katherine MacReynolds, Michael H. Francis, Ronald C. Wittmann, Douglas T. Tamura
This paper presents results of planar near-field measurements at 16, 35 and 94 GHz using probe position correction algorithms. The algorithms correct for position errors of the probe near the scan plane. The probe?s actual position is measured using a

Epitaxial growth of rhenium with sputtering

October 6, 2005
Author(s)
Seongshik Oh, Dustin P. Hite, Katarina Cicak, Kevin Osborn, Raymond W. Simmonds, Robert Mcdermott, Ken B. Cooper, Matthias Steffen, John M. Martinis, David P. Pappas
We have grown epitaxial renium (0001) films on α-Al 2O 3(0001) substrates using sputter deposition in an ultra high vacuum system. We find that better epitaxy is achieved with DC rather than with RF sputtering. With DC sputtering, epitaxy is obtained with

Propagation and Detection of Radio Signals Before, During, and After the Implosion of a Large Sports Stadium (Veterans Stadium in Philadelphia)

October 1, 2005
Author(s)
Christopher L. Holloway, Galen H. Koepke, Dennis G. Camell, Catherine A. Remley, Dylan F. Williams, Susan A. Schima, Seturnino Canales
In this report, we investigate radio communications problems faced by emergency responders (firefighters and police) in disaster situation such as collapsed buildings. A fundamental challenge to communications into and out of large buildings is the strong

Proximity effects in the calibration of microwave radiometers

October 1, 2005
Author(s)
Ronald C. Wittmann, Amanda Cox, Randy Direen
Microwave, total-power radiometers are calibrated by observing sources of known brightness temperature. Free-space calibrations are usually performed assuming far-field interactions, although the actual calibration source may be well into the near-field

HEB FPA Imaging Technology for Security and Biomedical Applications

September 19, 2005
Author(s)
Eyal Gerecht, Dazhen Gu, Sigfrid Yngvesson, Fernando Rodriguez-Morales, Ric Zannoni, John Nicholson
We have demonstrated a low-noise heterodyne three-element focal plane array (FPA) at 1.6 THz consisting of NbN Hot Electron Bolometric (HEB) detectors, intimately integrated with MMIC IF amplifiers in a single block. HEB technology is becoming the basis

Mutual phase-locking of microwave spin torque nano-oscillators

September 15, 2005
Author(s)
Shehzaad F. Kaka, Matthew Pufall, William Rippard, Thomas J. Silva, Stephen E. Russek, Jordan A. Katine
The spin torque effect that occurs in nanometre-scale magnetic multilayer devices can be used to generate steady- state microwave signals in response to a d.c. electrical current. This establishes a new functionality for magneto-electronic structures that

Impedance Control for Critically Coupled Cavities

August 31, 2005
Author(s)
Billy F. Riddle, Craig Nelson
Cavity resonators are often used in low phase noise oscillators that utilize carrier suppression. These oscillators are employed in systems that measure phase noise in frequencies as hight at 100 GHz. In order to achieve the maximum suppression needed in

Resonant microwave power absorption and relaxation of the energy levels of the molecular nanomagnet Fe 8 using superconducting quantum interference device-based magnetometry

August 15, 2005
Author(s)
Brant Cage, Stephen E. Russek, David Zipse, Micah North, Naresh S. Dalal
Energy levels and saturation of molecular nanomagnet Fe 8 crystals were investigated using a 95 and 141 GHz electron paramagnetic resonance (EPR) technique based on a standard superconducting quantum intererence device (SQUID) magnetometer. The technique

Injection Locking and Phase Control of Spin Transfer Nano-Oscillators

August 5, 2005
Author(s)
William Rippard, Matthew Pufall, Shehzaad F. Kaka, Thomas J. Silva, Stephen E. Russek, Jordan A. Katine
We have directly measured phase locking of spin transfer oscillators to an injected ac current. The oscillators lock to signals up to several hundred megahertz away from their natural oscillation frequencies, depending on the relative strength of the input

Uncertainties in Spherical Near-Field Antenna Measurements

August 3, 2005
Author(s)
Michael H. Francis, Ronald C. Wittmann, Jin-Seob Kang
A general approach is presented for estimating uncertainties in far-field parameters obtained from spherical near-field antenna measurements. The error is approximately bounded in terms of the uncertainty of the probe's receiving pattern and the

Microfabricated Atomic Frequency References

August 1, 2005
Author(s)
John Kitching, Svenja A. Knappe, Li-Anne Liew, John M. Moreland, Peter D. Schwindt, V Shah, V Gerginov, Leo W. Hollberg
Using microfabrication processes, we have been able to construct physics packages for vapour cell atomic frequency references 100x smaller than previously existing versions, with a corresponding reduction in power consumption. In addition, the devices

Critical-Current Measurements on ITER Nb3Sn Strands: Effect of Temperature

July 29, 2005
Author(s)
Loren F. Goodrich, Najib Cheggour, John (Jack) W. Ekin, Theodore C. Stauffer
Transport critical-current (II c) measurements were made on commercial multifilamentary Nb 3Sn strands at temperatures (T) from 4 to 17 K and magnetic fields (H) from 0 to 14 T. Samples investigated were taken from the stage 1 pre-production strand for the
Was this page helpful?