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Displaying 251 - 275 of 1560

A SMALL-SAMPLE, BI-DIRECTIONAL SCATTERING MEASUREMENT SYSTEM FROM 200-500 GHz

October 26, 2012
Author(s)
David R. Novotny, Josh Gordon, Edwin J. Heilweil, Brian C. Stillwell, Jeffrey R. Guerrieri, Erich N. Grossman, Shu Z. Lo
Beginning the fall of 2012, NIST will be providing scattering measurements for other government agencies. We present performance results of a bi-directional scattering measurement system in the 200-500 GHz range. The goal is to provide dense-spectrum, bi

An Improved Antenna Gain Extrapolation Measurement

October 20, 2012
Author(s)
Jason Coder, David R. Novotny, Jeffrey R. Guerrieri, Michael H. Francis, Brian C. Stillwell
An improved antenna gain extrapolation measurement is proposed. The improved method consists of a vector network analyzer, a pair of RF optical links, and a pair of waveguide mixers. We present a detailed description of the new extrapolation measurement

Noncontact measurement of charge carrier lifetime and mobility in GaN nanowires

August 27, 2012
Author(s)
Christopher M. Dodson, Patrick Parkinson, Kristine A. Bertness, Hannah J. Joyce, Laura M. Herz, Norman Sanford, Michael B. Johnston
The first noncontact photoconductivity measurements of gallium nitride nanowires (NWs) are presented, revealing a high crystallographic and optoelectronic quality achieved by use of catalyst-free molecular beam epitaxy. In comparison with bulk material

Early-time Behavior in Reverberation Chambers and Its Effect on the Relationships Between Coherence Bandwidth, Chamber Decay Time, RMS Delay Spread, and the Chamber Build-up Time

August 12, 2012
Author(s)
Christopher L. Holloway, Haider Shah, Ryan J. Pirkl, Catherine A. Remley, David A. Hill, John M. Ladbury
The use of reverberation chambers for electromagnetic testing is widely being accepted for use in many measurement applications. In recent years reverberation chambers are beginning to merge as a test facility for testing wireless device and for emulating

On Lower Bound Antenna Efficiency Measurements in a Reverberation Chamber

August 6, 2012
Author(s)
Jason B. Coder, John M. Ladbury
This paper addresses a few specific aspects of measuring the lower bound of antenna efficiency in a reverberation chamber. While the initial method for measuring the lower bound of efficiency has been presented, three key revisions are discussed here: (1)

Legendre Fit to the Reflection Coefficient of a Radiating Rectangular Waveguide Aperture

August 1, 2012
Author(s)
Dylan F. Williams, Mohammad T. Ghasr, Bradley K. Alpert, Zhongxiang Shen, Alexander Arsenovic, Robert M. Weikle, Reza Zoughi
We accurately calculate the reflection coefficient and normalized admittance of radiating open-ended rectangular waveguides and fit our results with a linear combination of Legendre polynomials. We verify the expression to an accuracy of 0.005 with other

Electromagnetic Properties of Iron Oxide Corrosion Product Powders at Radio Frequencies

July 1, 2012
Author(s)
Sung Kim, Jack T. Surek, James R. Baker-Jarvis, Virgil Provenzano
We calculated the refractive index from Sparameter data for corrosion samples tested in waveguide from 12.4 GHz to 110 GHz. This approach minimizes the modal noise often seen in derived permittivity and permeability for low-loss samples in this range. Also

Standardizing Rectangular Metallic Waveguides for Terahertz Applications

July 1, 2012
Author(s)
Ronald A. Ginley, N M. Ridler
This paper describes an on-going activity to develop an international document standard for defining rectangular metallic waveguides for use in the submillimeter-wave/terahertz frequency range. The IEEE's Microwave Theory & Techniques Society (MTT-S) is

Reverberation Chamber Measurement Correlation

June 15, 2012
Author(s)
Ryan J. Pirkl, Catherine A. Remley, Christian S. Lotback Patane
This contribution evaluates the utility of several different metrics for studying reverberation chamber measurement correlation. Metrics considered are the autocovariance, the correlation matrix, and two metrics based upon the entropy of the data

Frequency-selective contrast on variably doped p-type silicon with a scanning microwave microscope

May 14, 2012
Author(s)
Atif A. Imtiaz, Thomas M. Wallis, SangHyun S. Lim, H. Tanbakuchi, H-P Huber, A. Hornung, P. Hinterdorfer, J. Smoliner, F. Kienberger, Pavel Kabos
We report frequency dependent contrast in d(S11)/dV measurements of a variably doped p-type silicon sample in the frequency range from 2GHz to 18GHz. The measurements were conducted bys use of a scanning microwave microscope. The measurements were done at

Using Truncated Data Sets in Spherical Scanning Antenna Measurements

February 8, 2012
Author(s)
Ronald C. Wittmann, Carl F. Stubenrauch, Michael H. Francis
We discuss the mitigation of truncation errors in spherical scanning measurements. The main emphasis is the spherical harmonic representation of probe transmitting and receiving functions; however, our method is applicable to near-field measurement of
Displaying 251 - 275 of 1560