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Search Publications by: Dylan Williams ()

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Displaying 126 - 150 of 294

Use of Electronic Calibration Units for Vector-Network-Analyzer Verification

July 30, 2010
Author(s)
Dylan F. Williams, Arkadiusz C. Lewandowski, Denis X. LeGolvan, Ronald A. Ginley, Chih-Ming Wang, Jolene D. Splett
We present measurements indicating that electronic calibration units are stable enough to be used in place of mechanical vector-network-analyzer verification artifacts. This enables a new fully automated approach to verifying microwave vector-network

A New Electronic Verification Method for Vector Network Analyzers

June 13, 2010
Author(s)
Ronald A. Ginley, Dylan F. Williams, Denis X. LeGolvan
The National Institute of Standards and Technology (NIST) has recently introduced a new method for the verification of Vector Network Analyzers (VNAs). The technique is based on the new electronic calibration units that are available from several

Identifying RF Identification Cards from Measurements of Resonance and Carrier Harmonics

May 27, 2010
Author(s)
Henry Romero, Kate Remley, Dylan Williams, Chih-Ming Wang, Timothy X. Brown
We show that careful measurements of the unloaded resonant frequency and quality factor of radio frequency identification proximity cards allow identification of different card models and, for the set of cards we studied, identification with minimal error

Electro-optic sampling for traceable high-speed electrical measurements

May 23, 2010
Author(s)
Paul D. Hale, Dylan F. Williams
We will describe how the complex frequency response of a high-speed photodiode is calibrated by use of electro-optic sampling. Our uncertainty analysis includes a unique covariance-matrix based method that allows us to transform uncertainties between the

Towards Standardized Waveguide Sizes and Interfaces for Submillimeter Wavelengths

March 22, 2010
Author(s)
Ronald A. Ginley, Dylan Williams, N M. Ridler, J L. Hesler, Anthony R. Kerr, R D. Pollard
This paper describes an activity that has begun recently to develop an international standard for rectangular metallic waveguides and their interfaces for frequencies of 110 GHz and above. The IEEE's Microwave Theory and Techniques Society (MTT-S) is

Measurement Bandwidth Extension Using Multisine Signals: Propagation of Error

February 6, 2010
Author(s)
Catherine A. Remley, Dominique Schreurs, M. Myslinski, Dylan F. Williams
We describe a post-processing technique that can extend the effective measurement bandwidth of narrowband vector receivers by phase aligning overlapping measurements. The method requires only knowledge of the desired phases of a periodic, multisine

Comparison of Large-Signal-Network-Analyzer Calibrations

February 5, 2010
Author(s)
Dylan F. Williams, Catherine A. Remley, Joe Gering, Grand Aivazian
We develop a procedure and metrics for comparing large-signal-network-analyzer calibrations. The metrics we develop provide a bound on differences between measurements obtained from large-signal-network-analyzer calibrations, as well as more specific

Stochastic Modeling of Coaxial-Connector Repeatability Errors

November 30, 2009
Author(s)
Arkadiusz C. Lewandowski, Dylan F. Williams
We propose a new description of connector or repeatability errors for coaxial one-port devices. Our approach is based on a stochastic model constructed as a luped-element equivalent circuit with randomly varying frequency-independent parameters. We

Electronic Vector-Network-Analyzer Verification

October 1, 2009
Author(s)
Dylan F. Williams, Arkadiusz C. Lewandowski, Denis X. LeGolvan, Ronald A. Ginley
The National Institute of Standards and Technology (NIST) has just introduced a fully electronic measurement verification system for microwave vector-network-analyzer (VNA) calibrations called NISTeVerify. The system allows you to quickly verify VNA

Traceable waveform calibration with a covariance-based uncertainty analysis

October 1, 2009
Author(s)
Paul D. Hale, Dylan F. Williams, Andrew M. Dienstfrey, Arkadiusz C. Lewandowski, Tracy S. Clement, Darryl A. Keenan
We describe a method for calibrating the voltage that a step-like pulse generator produces at a load at every time point in themeasured waveform. The calibration includes an equivalent-circuit model of the generator that can be used to determine how the

Uncertainty of timebase corrections

October 1, 2009
Author(s)
Chih-Ming Wang, Paul D. Hale, Dylan F. Williams
We develop a covariance matrix describing the uncertainty of a new timebase for waveform measurements determined with the National Institute of Standards and Technology's timebase correction algorithm. This covariance matrix is used with covariance

Novel nano-structured Metal-Semiconductor-Metal photodetector with high peak voltage

June 22, 2009
Author(s)
Paul D. Hale, Dylan F. Williams, Tomoko Borsa, B. J. VanZeghbroeck
A novel nano-structured metal-semiconductor-metal photodetector consisting of interdigitated metal fingers and nanodots is successfully fabricated on a semi-insulating GaAs substrate by electron beam lithography, and integrated with an on-chip ground

Complete waveform characterization at NIST

June 8, 2008
Author(s)
Paul D. Hale, Tracy S. Clement, Darryl A. Keenan, Dylan F. Williams, Arkadiusz C. Lewandowski, C. M. Wang, Andrew Dienstfrey
We present a method for calibrating the voltage a pulse generator delivers to a load at every point in the measured waveform epoch. The calibration includes an equivalent circuit model of the generator so that the user can calculate how the generator will

The Beginnings of This TRANSACTIONS

March 1, 2008
Author(s)
Dylan F. Williams, Admir Mortazawi
In July, 1951, Ben Warriner (chairman, 1952-1953) circulated a petition to begin the Microwave Theory and Techniques Society under the auspices of the Institute of Radio Engineers. Despite an initial lack of support from the IRE, the roots of the

Comb-Generator Characterization

February 1, 2008
Author(s)
Howard C. Reader, Dylan Williams, Paul D. Hale, Tracy S. Clement
We characterize a 50 GHz comb generator measured on a sampling oscilloscope. With careful control of the input power, input harmonics and comb generator temperature, we find the output spectrum to be stable to 0.1 dB and 0.5 degrees. We correct results for

Absolute Magnitude and Phase Calibrations

October 1, 2007
Author(s)
Kate Remley, Paul D. Hale, Dylan Williams
In VNA measurements, the magnitude and phase of a transmitted or reflected wave are measured relative to that of the incident wave. VNA measurements are made a single frequency at a time and each frequency component is acquired relative to the internally

Chip-level Security for RFID Smart Cards and Tags

September 4, 2007
Author(s)
Dylan Williams, Kate Remley
This report on RFID chip-level security is written to help both technical and non-technical audiences navigate the complex chip-level security features of RFID smart cards and tags, and make intelligent security choices. The report explores both attacks

Systematic Error of the Nose-to-Nose Sampling-Oscilloscope Calibration

September 1, 2007
Author(s)
Dylan Williams, Tracy S. Clement, Kate Remley, Paul D. Hale, F. Verbeyst
We use traceable swept-sine and electrooptic-sampling-system-based-sampling-oscilloscope calibrations to measure the systematic error of the nose-to-nose calibration, and compare the results to simulations. Our results show that the errors in the nose-to

The Sampling Oscilloscope as a Microwave Instrument

August 1, 2007
Author(s)
Dylan Williams, Paul D. Hale, Kate Remley
Many modern high-speed oscilloscopes are well suited for precise microwave waveform, modulated-signal, and nonlinear measurements. These oscilloscopes have bandwidths of up to 100 GHz and are available with nominally 50 ? input impedances. Like their low

RFID Devices and Systems in Homeland Security Applications

July 1, 2007
Author(s)
Kate Remley, Jeffrey R. Guerrieri, Dylan Williams, David R. Novotny, Anthony B. Kos, Nelson Bryner, Nader Moayeri, Michael Souryal, Kang Lee, Steven Fick
This article reports on activities being carried out by the National Institute of Standards and Technology to ensure secure, reliable use of Radio-Frequency Identification (RFID) technology in homeland security and public safety applications. These

Compensation of Random and Systematic Timing Errors in Sampling Oscilloscopes

December 1, 2006
Author(s)
Paul D. Hale, C. M. Wang, Dylan Williams, Kate Remley, Joshua Wepman
In this paper, a method of correcting both random and systematic timebase errors using measurements of only two quadrature sinusoids made simultaneously with a waveform of interest is described. The authors estimate the fundamental limits to the procedure