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.

Search Publications by:

Search Title, Abstract, Conference, Citation, Keyword or Author
Displaying 1 - 25 of 93

Some Statistical Methods Applicable to Key Comparisons Studies

October 12, 2021
Author(s)
Hariharan K. Iyer, Chih-Ming Wang, Dominic F. Vecchia
Results of International Key Comparisons of National Measurement Standards provide the technical basis for the Mutual Recognition Arrangement formulated by Le Comite International des Poids et Mesures. With many key comparisons already completed and a

Calibration of free-space and fiber-coupled single-photon detectors

September 14, 2020
Author(s)
Thomas Gerrits, Alan L. Migdall, Joshua C. Bienfang, John H. Lehman, Sae Woo Nam, Oliver T. Slattery, Jolene D. Splett, Igor Vayshenker, Chih-Ming Wang
We present our measurements of the detection efficiency of free-space and fiber-coupled single- photon detectors at wavelengths near 851 nm and 1533.6 nm. We investigate the spatial uniformity of one free-space-coupled silicon single-photon avalanche diode

Calibration of free-space and fiber-coupled single-photon detectors

December 20, 2019
Author(s)
Thomas Gerrits, Alan L. Migdall, Joshua C. Bienfang, John H. Lehman, Sae Woo Nam, Jolene D. Splett, Igor Vayshenker, Chih-Ming Wang
We measure the detection efficiency of single-photon detectors at wavelengths near 851 nm and 1533.6 nm. We investigate the spatial uniformity of one free-space-coupled single-photon avalanche diode and present a comparison between fusion-spliced and

Low-temperature growth of carbon nanotubes catalyzed by sodium-based ingredients

May 27, 2019
Author(s)
Renu Sharma, Richard Li, Erica F. Antunes, Estekke Cohen, Akira Kudo, Luiz Acauan, Wei-Chang D. Yang, Chih-Ming Wang, Kehang Cui, Andrew Liotta, Ananth G. Rajan, Jules Gardner, David C. Bell, Michael S. Strano, James A. Liddle, Brian L. Wardle
Nanoparticle-catalytic synthesis of carbon nanostructures is an attractive route for producing 1-dimensional carbon nanomaterials, such as carbon nanotubes1 (CNTs), in large enough quantities for their multifunctional capabilities to be applied in

Estimating and Correcting the Device-Under-Test Transfer Function in Loaded Reverberation Chambers for Over-the-Air Tests

December 1, 2017
Author(s)
Catherine A. Remley, Ryan J. Pirkl, Chih-Ming Wang, Damir Senic, Arvand Homer, Matt V. North, Maria G. Becker, Robert D. Horansky, Christopher L. Holloway
We assess the potential error in measurements of the power transfer function corresponding to a reverberation chamber set-up when different antenna types are used for the reference and DUT measurements. We derive a mathematical description of the transfer

Progress on Single Photon Detector Efficiency Calibrations at NIST

June 14, 2017
Author(s)
Thomas Gerrits, John H. Lehman, Alan Migdall, Sae Woo Nam, Igor Vayshenker, Chih-Ming Wang
We report on our progress towards implementing a measurement service aimed at the calibration of single-photon detectors. We present how our calibration is tied to the calibration of our transfer standard optical fiber power meters. We also developed and

Using Absorption Cross Section to Predict Coherence Bandwidth and other Characteristics of a Reverberation Chamber Set-up for Wireless System Tests

October 3, 2016
Author(s)
Catherine A. Remley, Jos Dortmans, Damir Senic, Chih-Ming Wang, Christopher L. Holloway
We present a method to predict the coherence bandwidth, delay spread and power transfer function of a reverberation chamber set-up. The method is based on the absorption cross section of the absorbing material that is added to the chamber. With an S

Variability of Sounder Measurements in Manufacturing Facilities

June 27, 2016
Author(s)
Jeanne Quimby, Alexandra Curtin, David R. Novotny, Chih-Ming Wang, Rick Candell
Uncertainties in the linear regression fit of Path Loss are derived from variability in position. These uncertainties are used to determine the required positional accuracy for channel sounder measurements.

Configuring and Verifying Reverberation Chambers for Testing Cellular Wireless Devices

April 21, 2016
Author(s)
Catherine A. Remley, Jos N. Dortmans, Catherine Weldon, Thomas B. Meurs, Chih-Ming Wang, Christopher L. Holloway, Perry F. Wilson
Reverberation chambers provide a repeatable test environment for laboratory over-the-air testing and represent a viable solution for testing large-form-factor wireless devices. Such tests often involve “imperfect chamber” configurations in which the

Estimating and Reducing Uncertainty in Reverberation-Chamber Characterization at Millimeter-Wave Frequencies

April 20, 2016
Author(s)
Damir Senic, Catherine A. Remley, Chih-Ming Wang, Dylan F. Williams, Christopher L. Holloway, Diogo Ribeiro, Ansgar T. Kirk
This contribution provides techniques for accurately characterizing the measurement uncertainty due to chamber setup for total radiated power measurements at millimeter-wave frequencies. The setup is based on the reverberation chamber as a well-known

Using the Amplitude Variation of a Reverberation Chamber Channel to Predict the Synchronization of a Wireless Digital Communication Test System

August 16, 2015
Author(s)
Ray R. Tanuhardja, Luis A. Gonzalez, Chih-Ming Wang, William F. Young, Kate Remley
This contribution discusses the use of a metric based on the amplitude variation of a channel in the signal bandwidth to predict whether or not a digital wireless communication test system receiver will be able to demodulate a test signal. This metric is

Millimeter-Wave Modulated-Signal and Error-Vector-Magnitude Measurement With Uncertainty

May 1, 2015
Author(s)
Catherine A. Remley, Dylan F. Williams, Paul D. Hale, Chih-Ming Wang, Jeffrey A. Jargon, Youngcheol Park
We provide techniques to generate and characterize precision wideband millimeter-wave modulated signals. We use predistortion to obtain a significant improvement in signal quality and an associated reduction in the error vector magnitude (EVM) of the

A Compact Millimeter-wave Multisine Generator for Calibrating Broadband Vector Receivers

April 30, 2015
Author(s)
Paul D. Hale, Kate Remley, Dylan Williams, Jeffrey Jargon, Chih-Ming Wang
We propose a compact and low cost waveform source that can be used to calibrate the magnitude and phase response of vector receivers over a bandwidth as large as a few gigahertz. The generator consists of a broadband comb generator followed by a filter and

Proximity-effect test for lossy wireless-device measurements in reverberation chambers

January 4, 2015
Author(s)
Catherine A. Remley, Joop Aan Den Toorn, Christopher L. Holloway, John M. Ladbury, Chih-Ming Wang
We present a test method for quantifying and reducing systematic errors arising from antenna proximity to lossy objects in over-the-air performance testing of lossy large-form-factor wireless devices. The method determines the extent to which antenna

Parameter Estimation and Uncertainty Evaluation in a Low Rician K-Factor Reverberation-Chamber Environment

October 15, 2014
Author(s)
Chih-Ming Wang, Catherine A. Remley, Ansgar T. Kirk, Ryan J. Pirkl, Christopher L. Holloway, Dylan F. Williams, Paul D. Hale
In this paper we study statistical methods for estimating the Rician K-factor when this parameter is small. A fiducial approach for making statistical inference on the K-factor is discussed. The approach requires a Monte Carlo method to compute the

Statistical Sampling of Carbon Nanotube Populations by Thermogravimetric Analysis

December 25, 2013
Author(s)
Elisabeth Mansfield, Aparna Kar, Chih-Ming Wang, Ann C. Chiaramonti Debay
Carbon nanotubes are one of the most promising nanomaterials on the market, with applications in electronics devices, sensing, batteries, composites and medical communities. Strict control of the carbon nanotube chemistry and properties is necessary as the