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Displaying 351 - 375 of 1560

Near-Field Spherical Scanning: Quiet-Zone Field Evaluation

June 1, 2009
Author(s)
Randy Direen, Michael H. Francis, Ronald C. Wittmann
Spherical near-field scanning measurements are used to determine the incident electromagnetic fields within a test volume. Results from two independent approaches are compared and found to agree within estimated uncertainties.

Uncertainty Analysis for Noise-Parameter Measurements at NIST

April 9, 2009
Author(s)
James P. Randa
The uncertainty analysis is presented for NIST measurements of noise parameters of amplifiers and transistors, in both connectorized (coaxial) and on-wafer environments. We treat both the X-parameters, which are based on the wave representation of the

DC Internal Inductance for a Conductor of Rectangular Cross Section

April 3, 2009
Author(s)
Christopher L. Holloway, Edward Kuester
In this paper, the DC internal inductance for conductors with rectangular cross-section is investigated. Using a quasistatic Green's function, the magnetic fields inside a rectangular conductor are derived. These magnetic field expressions are used to

Variable Termination Unit for Noise-Parameter Measurements

April 1, 2009
Author(s)
Dazhen Gu, Dave K. Walker, James P. Randa
NIST has upgraded its measurement capability of noise parameters on low-noise amplifiers with a variable termination unit (VTU) in the 1 to 12.4 GHz frequency range. Such a unit allows improved time efficiency and accuracy in the noise-temperature

EEEL Technical Accomplishments

March 30, 2009
Author(s)
Erik M. Secula
This document describes the technical work of the Electronics and Electrical Engineering Laboratory. In this report, you will find that EEEL researchers are developing the world's most advanced sensors, providing advanced gamma ray imagers for astronomical

Electromagnetic Emissions and Performance for Proximity RFID

March 23, 2009
Author(s)
Jeffrey R. Guerrieri, David R. Novotny, Michael H. Francis, Catherine A. Remley
We examined the electromagnetic emissions, and performance of commercial High-Frequency (HF) proximity Radio Frequency Identification (RFID) systems including their susceptibility to jamming and eavesdropping. These proximity RFID systems are used in an

Measurements of Metamaterial-Inspired, Electrically Small Antenna Systems

March 2, 2009
Author(s)
Christopher L. Holloway, John M. Ladbury, Richard Ziolkowski, Peng Jin, Chia-Ching Lin
The paper discusses the analysis and measurements of electrical small antennas. The antennas discussed here are based on antenna designed from metamaterial inspired concepts. An electromagnetic reverberation chamber is used for the test of the antennas. A

Broadband Dielectric Spectroscopy of Ruddlesden-Popper Sr(n+1)Ti(n)O(3n+1) (n= 1, 2, 3) Thin Films

January 29, 2009
Author(s)
Nathan D. Orloff, Ichiro Takeuchi, James C. Booth, Dazhen Gu, Jordi Mateu, C. J. Fennie, K. M. Rabe, W Tian, D.G. Schlom
We explore the frequency dependent permittivity of Ruddlesden-Popper series Sr(n+1)Ti(n)O(3n+1) (n= 1, 2, 3) thin films as a function of temperature and dc electric-field. Interdigitated capacitors and coplanar waveguides are used to extract the frequency

Detection and segmentation of concealed objects in terahertz images

December 1, 2008
Author(s)
Xilin Shen, Charles Dietlein, Erich N. Grossman, Zoya Popovic, Francois Meyer
Terahertz imaging has been shown to successfully detect objects concealed underneath clothing, by measuring the radiometric temperatures of different objects on a human subject. The goal of this work is to automatically detect and segment concealed objects

Controlled Transport of Magnetic Particles Using Soft Magnetic Patterns

November 20, 2008
Author(s)
Richard Conroy, Gary Zabow, John M. Moreland, Alan P. Koretsky
Inspired by magnetic bubble memory technology, we demonstrate the temporal and spatial manipulation of superparamagnetic beads guided by soft magnetic patterns in a rotating magnetic field. Soft magnetic structures allow complex and repetitive tasks to be

Using Reverberation Chambers to Determine the Shielding Effectiveness of Physically Small, Electrically Large Enclosures/Cavities

November 20, 2008
Author(s)
Christopher L. Holloway, David A. Hill, Marco Sandroni, John M. Ladbury, Jason B. Coder, Galen H. Koepke, Andrew C. Marvin
With the proliferation of small electric devices in recent years, along with various other applications, there is a growing need to test and determine the shielding properties or shielding effectiveness (SE) of physically small (but electrically large)

HF Proximity RFID Electromagnetic Emissions and Performance

November 16, 2008
Author(s)
Jeffrey R. Guerrieri, David R. Novotny, Catherine A. Remley, Michael H. Francis
We examined the emissions, and performance of commercial High-Frequency Radio Frequency Identification (HF RFID) systems to interrupt and eavesdropping. These proximity RFID systems are used in an increasing number of financial, identification, and access

Near-Field Spherical Scanning: Uncertainties in Test-Zone Field Measurements

November 16, 2008
Author(s)
Randy Direen, Ronald C. Wittmann, Michael H. Francis
The electromagnetic field within a test volume can be measured using spherical scanning techniques. Characterization of the field within the sphere requires compensation for probe-pattern effects. We provide a simple uncertainty analysis to estimate

HF RFID Electromagnetic Emissions and Performance

November 4, 2008
Author(s)
David R. Novotny, Jeffrey R. Guerrieri, Michael H. Francis, Catherine A. Remley
We examined the emissions, and susceptibility of commercial High-Frequency Radio Frequency Identification (HF proximity RFID) systems to interrupt and eavesdropping. RFID systems are being used in an increasing number of financial, identification, and

Probability Density Function of Power Received in a Reverberation Chamber

November 2, 2008
Author(s)
David A. Hill
The probability density function (PDF) for the power received by an arbitrary antenna in a reverberation chamber has been shown to be exponential. The purpose of this correspondence is to provide a direct maximum-entropy derivation of the PDF that deals

In-Situ Torque Magnetometry: Magnetic Coupling in Fe/Cr/Fe Thin-Film Systems

October 31, 2008
Author(s)
Dong-Hoon Min, S. B. Lee, John M. Moreland
We have developed an ultra-sensitive torque magnetometer tailored to the study of thin-film interface magnetism and interlayer magnetic exchange coupling. The magnetometer was composed of an optical-fiber interferometer and a customized silicon cantilever

Aqueous blackbody calibration source for millimeter-wave/terahertz metrology

October 20, 2008
Author(s)
Charles Dietlein, Zoya Popovic, Erich N. Grossman
This paper describes a calibrated broadband emitter for the millimeter-wave through terahertz frequency regime, called the aqueous blackbody calibration source. Due to its extremely high absorption, liquid water is chosen as the emitter on the basis of
Displaying 351 - 375 of 1560