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Search Publications by: Christopher L. Holloway (Fed)

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Displaying 151 - 175 of 213

On the Use of Reverberation Chambers to Simulate a Controllable Rician Radio Environment for the Testing of Wireless Devices.

November 1, 2006
Author(s)
Christopher L. Holloway, David A. Hill, John M. Ladbury, Perry F. Wilson, Galen H. Koepke, Jason Coder
With the proliferation of wireless devices in recent years, there is a growing need to test the operation and functionality of these various devices in different multipath radio propagation environments, ranging from a direct line-of-sight environment to a

Phase Velocity in Resonant Structures

October 1, 2006
Author(s)
James R. Baker-Jarvis, Michael D. Janezic, Derik Love, Thomas Mitchell (Mitch) Wallis, Christopher L. Holloway, Pavel Kabos
In this paper we present a simple experimental procedure for studying the phase velocity behavior of a metafilm with tunable material properties. Using this approach we have studied the phase-velocity behavior of a metamaterial under different conditions

Propagation and Detection of Radio Signals Before, During, and After the Implosion of a Large Convention Center

October 1, 2006
Author(s)
Christopher L. Holloway, Galen H. Koepke, Dennis G. Camell, Catherine A. Remley, Susan A. Schima, M. McKinley, Robert T. Johnk
In this report, we investigate radio communications problems faced by emergency responders (firefighters and police) in disaster situations such as collapsed buildings. A fundamental challenge to communications into and out of large buildings is the strong

Shielding And Attenuation Properties of Large Buildings and Structures

September 4, 2006
Author(s)
Christopher L. Holloway, Galen H. Koepke, Dennis G. Camell, Kate Remley, S. A. Schima, Dylan Williams
For various applications, there is a growing need to understand the shielding and/or attenuation properties of large buildings and structures. In this paper, we present experimental data for the coupling of electromagnetic fields into various types of

Radio Communications for Emergency Responders in Large Public Buildings: Comparing Analog and Digital Modulation

March 7, 2006
Author(s)
Catherine A. Remley, Marc Rutschlin, Dylan F. Williams, Robert T. Johnk, Galen H. Koepke, Christopher L. Holloway, Mike G. Worrell, Andy MacFarlane
To assess in-building radio coverage, in 2004 the City of Phoenix Fire Department carried out extensive testing of their radio systems. They deployed firefighters in standard configurations in a variety of buildings, and rated on a scale of 1 to 5 the

Requirements for an Effective Reverberation Chamber: Unloaded or Loaded

February 1, 2006
Author(s)
Christopher L. Holloway, David A. Hill, Galen H. Koepke, John M. Ladbury
In this paper we present two versions of a threshold metric for the purpose of accessing the effectiveness of a reverberation chamber. One metric is based on the chamber quality factor (Q), and the other is based on the volume of the loaded reverberation

Analyzing Carbon Fiber Composite Materials with Equivalent Layer

November 1, 2005
Author(s)
Christopher L. Holloway, M. S. Sarto, Martin Johansson
The purpose of this paper is toinvestigate the use of effective layer models for the analysis of carbon fiber composite materials. In this paper, we present three different models for the electromagnetic characterization (effective material properties) of

Realization of a Controllable Metafilm (''Smart Surface'') Composed of Resonant Magnetodielectric Particles: Measurements and Theory

November 1, 2005
Author(s)
Christopher L. Holloway, Pavel Kabos, Mohamed Mohamed, Edward Kuester, Michael D. Janezic, James R. Baker-Jarvis
In previous work, we derived generalized sheet-transition conditions (GSTCs) for the average electromagnetic fields across a metafilm, which, when properly designed, can have certain desired reflection and transmission properties. A metafilm is the two

Propagation and Detection of Radio Signals Before, During, and After the Implosion of a Large Sports Stadium (Veterans’ Stadium in Philadelphia)

October 1, 2005
Author(s)
Christopher L. Holloway, Galen H. Koepke, Dennis G. Camell, Catherine A. Remley, Dylan F. Williams, Susan A. Schima, Seturnino Canales
In this report, we investigate radio communications problems faced by emergency responders (firefighters and police) in disaster situation such as collapsed buildings. A fundamental challenge to communications into and out of large buildings is the strong

Propagation and Detection of Radio Signals Before, During, and After the Implosion of a 13-Story Apartment Building

May 1, 2005
Author(s)
Christopher L. Holloway, Galen H. Koepke, Dennis G. Camell, Catherine A. Remley, Dylan F. Williams, Susan A. Schima, Seturnino Canales, Douglas T. Tamura
In this report we investigate communications problems faced by emergency responders (firefighters and police) in disaster situations (i.e., collapsed buildings). A fundamental challenge to communications into large building structures is the strong

The OATS Method Revisited

April 1, 2005
Author(s)
Christopher L. Holloway, Perry F. Wilson, Robert German
Open area test sites (OATS) or equivalent semi-anechoic chambers are the most commonly used sites for EMC emissions tests. This article discusses the origins of this test methodology and revisits the interference problem (broadcast media) that the OATS

Radio Propagation Measurements During a Building Collapse: Applications for First Responders

March 3, 2005
Author(s)
Christopher L. Holloway, Galen H. Koepke, Dennis G. Camell, Catherine A. Remley, Dylan F. Williams
The National Institute of Standards and Technology is involved in a research project to improve wireless communications for first responders (firefighters and police) in large structures (i.e., large apartment and office buildings, supermarkets, sports

Optimized Arbitrary Wireless Device Arrays for Emergency Response Communications

March 1, 2005
Author(s)
William F. Young, Edward Kuester, Christopher L. Holloway
Wireless communications are essential to emergency responders. Unfortunately, a typical emergency response scenario involves communication into and within structures, which severely interfere with or completely block the radio frequency channel. In this

Measuring the Permittivity and Permeability of Lossy Materials: Solids, Liquids, Metals, and negative-Index Materials

February 1, 2005
Author(s)
James R. Baker-Jarvis, Michael D. Janezic, Billy F. Riddle, Robert T. Johnk, Christopher L. Holloway, Richard G. Geyer, Chriss A. Grosvenor
The goal of this report is to be a comprehensive guide for researchers int he area of dielectric and magnetic measurements of lossy materials. The goal is to assemble the relevant information needed to perform and interpret dielectric measurements on lossy

Wide-Band Slot Antennas with CPW Feed Lines: Hybrid and Log-Periodic Designs

October 11, 2004
Author(s)
Alpesh Bhobe, Christopher L. Holloway, Melinda Piket-May, Richard Hall
In microwave and millimeter wave applications, slot antennas fed by coplanar waveguides (CPW) are receiving increasing attention. These antennas have several useful properties, such as wider bandwidth as compared to microstrip patch antennas and easier

The Effects of Loading Configurations on the Performance of Reverberation Chambers

September 6, 2004
Author(s)
Christopher L. Holloway, Todd Lammers, John M. Ladbury
The presence of lossy objects in reverberation chamber may significantly disturb the reverberant environment and affect the desired field statistics. In this paper, we present a numerical study of the effects of different loading configurations on the