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Search Publications

NIST Authors in Bold

Displaying 276 - 300 of 1560

A Novel Method for Determining the Lower Bound of Antenna Efficiency

December 31, 2011
Author(s)
Jason B. Coder, John M. Ladbury, Mark Golkowski
Determining the absolute antenna efficiency has been a difficult task since the inception of the antenna itself. While there are methods that can measure an antenna’s efficiency, most are complicated and prone to high uncertainties. A new method is

A Large-Signal Model of Ferroelectric Thin-Film Transmission Lines"

December 1, 2011
Author(s)
Eduard Rocas, Juan C. Collado Gomez, Jordi Mateu, Nate Orloff, James Booth, Juan M. O'C allaghan
"This work evaluates the microwave nonlinear properties and tuning at RF frequencies of ferroelectric Ba0.3Sr0.7TiO3 thin-films by on-wafer measurements of the second and third-order harmonics and intermodulation products of several coplanar transmission

Verification of Noise-Parameter Measurements and Uncertainties

November 1, 2011
Author(s)
James P. Randa, Dazhen Gu, Dave K. Walker
We propose and implement verification methods for measurements of noise parameters of amplifiers and transistors. Because the verification rests on the comparison of different measurement results, it also serves as a test of the uncertainties. The

500 GHz - 750 GHz Rectangular-Waveguide Vector-Network-Analyzer Calibrations

October 31, 2011
Author(s)
Dylan F. Williams
We develop an uncertainty analysis that captures the dominant sources of measurement error in state-of-the-art rectangular-waveguide vector-network-analyzer measurements over the frequency range 500 GHz – 750 GHz. We use the analysis to assess thru-reflect

On-Chip Security Using Electromagnetic Analysis

October 27, 2011
Author(s)
James Schaffner, Dylan Williams
In this report we describe a test bed designed to assess the vulnerabilities of security microcontrollers to electromagnetic monitoring, and use the test bed to show that it is indeed possible to gather more local information from electromagnetic

Effective Material Property Extraction Of a Metamaterial by Taking Boundary Effects into Account At TE/TM Polarized Incidence

September 22, 2011
Author(s)
Sung Kim, Christopher L. Holloway, James R. Baker-Jarvis, Edward Kuester, Kendra L. Kimberly
In this paper, we present the extraction for effective material parameters for a metamaterial from TE or TM waveguide measurements with generalized sheet transition conditions (GSTCs) used to provide electric and magnetic surface susceptibilities that

Terahertz metrology and instrumentation

August 29, 2011
Author(s)
Erich N. Grossman, Zoya Popovic
This paper gives an overview of measurement techniques used in the THz region of the electromagnetic spectrum, from about 100 GHz to several THz. Currently available components necessary for THz metrology, such as sources, detectors and passives, are

Measurement of Shielding Effectiveness of Electrically-Small Enclosures

August 13, 2011
Author(s)
Christopher L. Holloway, Colton R. Dunlap, John M. Ladbury, Joshua A. Gordon, Jason B. Coder, Galen H. Koepke
In the following we propose a technique for determining the shielding effectiveness (SE) an electrically small enclosure. In particular, we use this technique to explore the shielding characteristics of a rectangular box used to shield a satellite based

An Electromagnetic Evaluation of the NASA Space Power Facility at Plum Brook Station

July 1, 2011
Author(s)
Galen H. Koepke, John M. Ladbury, Dennis G. Camell, Jason B. Coder, Chriss A. Grosvenor, Randy Direen, Jeffrey R. Guerrieri
We describe in this report (Technical Note) an extensive electromagnetic evaluation of a unique test facility designed and built by the National Aeronautics and Space Administration (NASA). The Space Power Facility is presumed to be the world’s largest

Electrical Characterization of Photoconductive GaN Nanowire Devices from 50 MHz to 33 GHz

July 1, 2011
Author(s)
Thomas M. Wallis, Dazhen Gu, Atif A. Imtiaz, Pavel Kabos, Paul T. Blanchard, Norman A. Sanford, Kristine A. Bertness, Christpher Smith
The electrical response of two-port., photoconductive GaN nanowire devices was measured from 50 MHz to 33 GHz. The admittance of individual contacted nanowires showed an increase on the order of 10% throughout the measured frequency range after exposure to

Recent Developments in Millimeter and Submillimeter Metrology at NIST

June 30, 2011
Author(s)
Ronald A. Ginley
The millimeter and submillimeter frequency ranges are becoming very important to today’s electronics, security and communication industries. NIST has undertaken a research program to aggressively pursue this area. This paper will cover the millimeter

A general approach to low noise readout of terahertz imaging arrays

June 16, 2011
Author(s)
Erich N. Grossman, Jonathan D. Chisum, Zoya Popovic
This article describes the theory and design of an ultra-low noise electronic readout circuit for use with room temperature video-rate terahertz imaging arrays. First, the noise characteristics of various imaging detectors, including low resistance

PDH-locked, frequency-stabilized cavity ring-down spectrometer

June 16, 2011
Author(s)
Joseph T. Hodges, A. Cygan, Piotr Maslowski, Katarzyna E. Bielska, S. Wojtewicz, J. Domyslawska, Hisashi Abe, R.S. Trawinski, R. Ciurylo
We describe a high sensitivity and high spectral resolution laser absorption spectrometer based upon the frequency-stabilized cavity ring-down spectroscopy (FS-CRDS) technique. We used the Pound-Drever-Hall (PDH) method to lock the probe laser to the high

Development of a multifilament PIT V3Ga conductor for fusion applications

June 12, 2011
Author(s)
Najib Cheggour, Theodore C. Stauffer, Loren F. Goodrich, L. R. Motowidlo, J Distin, P. J. Lee, David C. Larbalestier, A. K. Ghosh
Previous studies on V3Ga assert its suitability for use in proposed fusion reactors. V3Ga may outperform Nb3Sn in a fusion reactor environment based on its relatively flat critical-current profile in the 15 T- 20 T range, resilience to applied strain, and

Strain and Magnetization Properties of High Subelement Count Tube-type Nb3Sn Strands

June 6, 2011
Author(s)
Najib Cheggour, X Peng, E Gregory, M Tomsic, M D. Sumption, A. K. Ghosh, Xifeng Lu, Theodore C. Stauffer, Loren F. Goodrich, Jolene D. Splett
Abstract—A tubular technique for economical production of Nb3Sn material with large numbers of subelements is being explored by Supergenics I LLC and Hyper Tech Research Inc. The number of subelements was increased to 919 (744 subelements plus 175 Cu

Boundary Effects on the Determination of the Effective Parameters of a Metamaterial from Normal Incidence Reflection and Transmission

June 1, 2011
Author(s)
Sung Kim, Edward E. Kuester, Christopher L. Holloway, James R. Baker-Jarvis, Aaron D. Scher
This paper presents a method for the determination of the effective electromagnetic parameters of a metamaterial, taking boundary effects at the interfaces between a conventional material and metamaterial into account. In the technique presented here

Microwave Characterization of Transparent Conducting Films

May 26, 2011
Author(s)
Jan Obrzut, Oleg A. Kirillov
The high frequency conductivity of thin metallic and graphitic nano-films attracts interest due to many potential applications in spin electronics, electromagnetic shielding, flexible antennas, displays, and solar cells. The surface morphology of thin

Fluid interactions with metafilm/metasurfaces for tuning, sensing, and microwave assisted chemical processes

May 25, 2011
Author(s)
Joshua A. Gordon, Christopher L. Holloway, James C. Booth, James R. Baker-Jarvis, David R. Novotny, Sung Kim, Yu Y. Wang
In this paper we demonstrate tunability of a metafilm, which is the two-dimensional equivalent of a metamaterial, also referred to as a metasurface, by changing the permittivity in a micro-fluidic channel that interacts with the metafilm. Numerical
Displaying 276 - 300 of 1560