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Search Publications by: Christopher L. Holloway (Fed)

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Displaying 51 - 75 of 211

An Overview of Atom-Based SI-Traceable Electric-Field Metrology

October 30, 2016
Author(s)
Joshua A. Gordon, Christopher L. Holloway, Matthew T. Simons
We present an overview of radio frequency (RF) electric-field measurements using Rydberg atoms. This technique exploits the rich resonance response of these atoms which can occur across a large frequency range from 1 GHz-500 GHz. This measurement utilizes

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

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 Frequency Detuning to Improve the Sensitivity of Electric Field Measurements via Electromagnetically Induced Transparency and Autler-Townes Splitting In Rydberg Atoms

March 14, 2016
Author(s)
Christopher L. Holloway, Matthew T. Simons, Joshua A. Gordon
In this work we demonstrate an approach for improved sensitivity in weak RF electric-field measurements using Rydberg EIT in an atomic vapor. This is accomplished by varying the RF frequency around a resonant atomic transition and extrapolating the weak on

Absorption Cross Section Measurements of a Human Body in a Reverberation Chamber

February 8, 2016
Author(s)
Damir Senic, Antonio Sarolic, Zbigniew M. Joskiewicz, Christopher L. Holloway
We provide the results of human body absorption cross section (ACS) measurements. The setup was based on the reverberation chamber as a well-known measurement environment capable of performing ACS measurements. The approach was supported by reference

Peer-to-Peer Urban Channel Characteristics for Two Public-Safety Frequency Bands

October 1, 2015
Author(s)
Catherine A. Remley, David W. Matolak, Camillo A. Gentile, Christopher L. Holloway, Qiong Wu, Qian Zhang
We report on ground-based wireless channel characteristics for an urban environment in two public safety bands. Results are based upon measurements taken in Denver in June 2009. The public safety bands we investigated are the 700 MHz and 4.9 GHz bands

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

Absorption Characteristics and SAR of a Lossy Sphere inside a Reverberation Chamber

September 1, 2014
Author(s)
Christopher L. Holloway, Damir Senic, John M. Ladbury, Galen H. Koepke
This study presents an experimental approach to the analysis of absorption characteristics of a lossy dielectric object in a reverberant environment. The study used a canonically shaped water-filled sphere, convenient for ACS calculations (analytical or by

Broadband Rydberg Atom Based Self-Calibrating RF E-field Probe

August 16, 2014
Author(s)
Christopher L. Holloway, Joshua A. Gordon, Steven R. Jefferts, Thomas P. Heavner
We present a significantly new approach for an electric (E) field probe. The probe is based on the interaction of RF-fields with Rydberg atoms, where alkali atoms are excited optically to Rydberg states and the applied RF-field alters the resonant state of

Radiowave Propagation in Urban Environments with Application to Public-Safety Communications

August 4, 2014
Author(s)
William F. Young, Catherine A. Remley, Christopher L. Holloway, Galen H. Koepke, Dennis G. Camell, John M. Ladbury, Colton R. Dunlap
We characterize key elements that pose challenges to public-safety radio communications into and out of large buildings, including the strong attenuation of radio signals caused by losses and scattering in the building materials and structure, and the