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Search Publications by: Michael H. Francis (Assoc)

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Displaying 76 - 100 of 188

HF RFID Electromagnetic Emissions and Performance

November 4, 2008
Author(s)
David R. Novotny, Jeffrey R. Guerrieri, Michael H. Francis, Catherine A. Remley
We examined the emissions, and susceptibility of commercial High-Frequency Radio Frequency Identification (HF proximity RFID) systems to interrupt and eavesdropping. RFID systems are being used in an increasing number of financial, identification, and

Chamber Imaging Using Spherical Near-Field Scanning

July 5, 2008
Author(s)
Ronald C. Wittmann, Michael H. Francis, Randy Direen
We discuss recent measurements performed at the National Institute of Standards and Technology (NIST) that were used to characterize the incident fields within a test volume and to produce images of the test chamber.

Near-field Scanning Measurements: Theory and practice

July 3, 2008
Author(s)
Michael H. Francis, Ronald C. Wittmann
This chapter summarizes theoretical and practical aspects of near-field scanning methods. These methods allow complete characterization of the transmitting or receiving properties using measurements made in close proximity to an antenna.

ANTENNA TEST RANGE IMAGING USING SPHERICAL NEAR-FIELD SCANNING

June 8, 2008
Author(s)
Michael H. Francis, Ronald C. Wittmann, Randy Direen
Although the theory is straightforward, practical implementation of spherical near-field scanning for evaluating test chambers presents some significant challenges. Among these are the selection of an appropriate probe and the difficulty in minimizing

Sources of Uncertainty for Near-Field Measurements

November 11, 2007
Author(s)
Michael H. Francis, Ronald C. Wittmann
We discuss the sources of uncertainty in near-field measurements and their impact on far-field antenna parameters. The methods of estimating these uncertainties can be considered in three broad categories: theoretical estimation (analytical), computer

RFID-Assisted Indoor Localization and Communication for First Responders

October 1, 2006
Author(s)
Jeffrey R. Guerrieri, Michael H. Francis, Perry F. Wilson, Leonard E. Miller, Nelson Bryner, David Stroup, Luke Klien-Berndt
An indoor localization and communication project is described that proposes to use RFID (radio-frequency identification) tags, placed in the building beforehand, as navigation waypoints for an inertial navigation system carried by a first responder. RFID

Three-Antenna Extrapolation Gain Measurement System at Millimeter Wave Frequencies

October 1, 2006
Author(s)
Katherine MacReynolds, Jeffrey R. Guerrieri, Michael H. Francis, Douglas T. Tamura
This paper describes the new tabletop millimeter wave extrapolation range which will provide on-axis gain services up to 110GHz. A discussion of the extrapolation measurement method [1], as presented at the Antenna Measurements Techniques Association (AMTA

RFID-Assisted Indoor Localization and Communication for First Responders

March 7, 2006
Author(s)
Leonard E. Miller, Perry F. Wilson, Nelson P. Bryner, Michael H. Francis, Jeffrey R. Guerrieri, D W. Stroup, Luke Klein-Berndt
An indoor localization and communication project is described that proposes to use RFID tags, placed in the building beforehand, as navigation waypoints for an inertial navigation system carried by a first responder. The findings from the first year of the

Comparison of Gains Determined from the Extrapolation and Pattern Integration Methods

October 30, 2005
Author(s)
Michael H. Francis, Katherine MacReynolds, Jeffrey R. Guerrieri
Scientists at the National Institute of Standards (NIST) have measured the gain of several antennas using two different methods. The first method is the three-antenna extrapolation method developed at NIST in the early 1970s. The second method is the

Planar Near-Field Measurements Results up to 94 GHz Using Probe Position Correction

October 30, 2005
Author(s)
Jeffrey R. Guerrieri, Katherine MacReynolds, Michael H. Francis, Ronald C. Wittmann, Douglas T. Tamura
This paper presents results of planar near-field measurements at 16, 35 and 94 GHz using probe position correction algorithms. The algorithms correct for position errors of the probe near the scan plane. The probe?s actual position is measured using a

Uncertainties in Spherical Near-Field Antenna Measurements

August 3, 2005
Author(s)
Michael H. Francis, Ronald C. Wittmann, Jin-Seob Kang
A general approach is presented for estimating uncertainties in far-field parameters obtained from spherical near-field antenna measurements. The error is approximately bounded in terms of the uncertainty of the probe's receiving pattern and the