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Displaying 426 - 450 of 718

Electrical material property measurements using a free-field, ultra-wideband system

October 1, 2004
Author(s)
Chriss A. Grosvenor, Robert T. Johnk, David R. Novotny, Seturnino Canales, James R. Baker-Jarvis, Michael D. Janezic, Jim L. Drewniak, Marina Kolednitseva, Jianmin Zhang, Poornachander Rawa
Abstract: Nondestructive measurements of materials using TEM horn antennas and an ultra-wideband measurement system are presented. Time-domain gating and genetic algorithms are used to process the data and extract the dielectric properties of the material

Lumped-Parameter Thermal Modeling of an IPEM using Thermal Component Models

August 15, 2004
Author(s)
J J. Rodriguez, Allen R. Hefner Jr., David W. Berning, M Velez-Reyes, Madelaine H. Hernandez, Jorge Gonz?lez
A thermal model for the CPES IPEM Gen. II is presented. The selected approach is the simulation of the thermal behavior of an experimental IPEM testbed using the 1D finite difference method. An equivalent electrical network representation of the thermal

TEM horn antennas: A promising new technology for compliance testing

August 1, 2004
Author(s)
Chriss A. Grosvenor, Robert T. Johnk, David R. Novotny, Seturnino Canales
Abstract-This paper discusses the advantages of using a TEM-horn antenna over conventional EMC antennas such as the log-periodic, hybrids, or biconical antennas. Important issues such as frequency coverage, linearity, time-resolution of events, cost, and

Mems-Based Embedded Sensor Virtual Components for SOC

June 24, 2004
Author(s)
Muhammad Afridi, Allen R. Hefner Jr., David W. Berning, Colleen E. Hood, Ankush Varma, Bruce Jacob, Stephen Semancik
The design and implementation of a monolithic MEMS-based (Micro Electro Mechanical Systems) gas sensor virtual component is described. A bulk micromachining technique is used to create suspended microhotplate structures. The thermal properties of the

Reliability of SiC MOS Devices

June 24, 2004
Author(s)
Ranbir Singh, Allen R. Hefner Jr.
Fundamental limitations to oxide reliability are analyzed in silicon carbide based devices. A barrier height primarily determined by band offsets between metal/SiC and the dielectric, and the electric field in the dielectric results in tunneling current

Checks of Amplifier Noise-Parameter Measurements

June 11, 2004
Author(s)
James P. Randa, Dave K. Walker
We propose two verification methods for measurements of noise parameters of amplifiers, particularly low-noise amplifiers (LNAs). One method is a direct measurement of the parameter Trev, the noise temperature from the amplifier input, and the comparison

Radiometer Measurements of a Near-Ambient, Variable-Temperature Noise Standard

June 7, 2004
Author(s)
George Free, James P. Randa, Robert L. Billinger
A near-ambient, variable-temperature noise standard whose physical temperature can be accurately measured was constructed and then measured with the NIST total-power radiometer to test the accuracy of radiometer measurements in the temperature range of 263

Practical electron-tunneling refrigerator

January 21, 2004
Author(s)
Anna Clark, Anthony Williams, Steve Ruggiero, Marcel L. van den Berg, Joel N. Ullom
We demonstrate a thin-film, solid-state refrigerator based on the removal of hot electrons from a metal by quantum-mechanical tunneling. We have halved the electronic temperature in a macroscopic film from 260 mK to near 130 mK. Both the cooling power and

Dilute Al-Mn alloys for superconductor device applications

December 17, 2003
Author(s)
Steve Ruggiero, Anthony Williams, W. H. Rippard, A. Clarke, Steven Deiker, Leila R. Vale, Joel N. Ullom
We discuss results on the superconducting and electron-transport properties of Mn doped Al produced by sputter deposition. The critical temperature of Al has been systematically reduced to below 50 mK by doping with 1000-3000 ppm Mn. Values of the α

Direct observation of photon pairs at a single output port of a beam-splitter interferometer

December 16, 2003
Author(s)
Matthew Shaw, Giovanni Di Giuseppe, A. Sergeinko, Bahaa E. A. Saleh, Malvin C. Teich, Aaron J. Miller, Sae Woo Nam
The seminal experiment carried out by Hong, Ou, and Mandel some fifteen years ago is one of the most important in the annals of quantum optics. This experiment demonstrated that two indistinguishable photons incident on a simple beam splitter interfere in

EMI Characterization with Parasitic Modeling for a Permanent Magnet Motor Drive

October 12, 2003
Author(s)
Xudong Huang, Pepa Elton, Jih-Sheng Lai, Allen R. Hefner Jr., David W. Berning, Shaotang Chen, Thomas Nehl
In this paper , a permanent magnet ac motor drive is tested extensively, and the prominent frequencies are identified for their relationship with the noise sources and their propagation paths. Switching characteristics of the power MOSFETs are evaluated

High Speed IGBT Module Transient Thermal Response Measurements for Model Validation

October 12, 2003
Author(s)
David W. Berning, John V. Reichl, Allen R. Hefner Jr., Mora Hernandez, Colleen E. Hood, Jih-Sheng Lai
A measurement system operates a multi-chip insulated gate bipolar transistor (IGBT) that is part of an integrated power electronic module (IPEM) in a high-pulsed-power linear mode for validation of dynamic thermal models. It is found that the gate-cathode

The Role of Carrier Lifetime in Forward Bias Degradation of 4H-SiC PiN Diodes

October 5, 2003
Author(s)
Allen R. Hefner Jr., Ty R. McNutt, David W. Berning, Ranbir Singh, Adwoa Akuffo
Abstract. The role of excess carrier lifetime reduction in the mechanism for on-state voltage (Vf) degradation of high voltage 4H-SiC PiN diodes is investigated. A method is developed to electrically monitor the emitter, base, and end region excess carrier

Prototype system for superconducting quantum interference device multiplexing of large-format transition-edge sensor arrays

September 25, 2003
Author(s)
Carl D. Reintsema, Joern Beyer, Sae Woo Nam, Steven Deiker, Gene C. Hilton, Kent D. Irwin, Joel N. Ullom, Leila R. Vale, Michael MacIntosh
We discuss the implementation of a time-division SQUID multiplexing system for the instrumentation of large-format transition-edge sensors (TES) arrays. We cover design and integration issues concerning cryogenic SQUID multiplexers and amplifiers, signal

Silicon Carbide Power MOSFET Model and Parameter Extraction Sequence

June 11, 2003
Author(s)
Ty R. McNutt, Allen R. Hefner Jr., Alan Mantooth, David W. Berning, Sei-Hyung Ryu
A compact circuit simulator model is used to describe the performance of a 2000-V, 5-A 4-H Silicon Carbide (SiC) power DiMOSFET and to perform a detailed comparison with the performance of a widely used 400-V, 5-A Silicon (Si) power MOSFET. The model's

The NIST Microforce Realization and Measurement Project

April 1, 2003
Author(s)
David B. Newell, Edwin R. Williams, John A. Kramar, Jon R. Pratt, Douglas T. Smith
The National Institute of Standards and Technology (NIST) has launched a five-year Micro-force Realization and Measurement project focusing on the development of an instrument and laboratory capable of realizing and measuring the SI unit of force below

Research on Site Qualifications above 1 GHz

February 18, 2003
Author(s)
Michael Windler, Dennis G. Camell
This is a summary of recent efforts conducted under the auspices of the American National Standards Institute (ANSI) Accredited Standards Committee C63, Sub-committee 1, working group 1-13.2. The main purpose of this group is to assess the applicability of

A Monolithic CMOS Microhotplate-based Gas Sensor System

December 1, 2002
Author(s)
Muhammad Afridi, John S. Suehle, Mona E. Zaghloul, David W. Berning, Allen R. Hefner Jr., Richard E. Cavicchi, Stephen Semancik, C B. Montgomery, C J. Taylor
A monolithic CMOS microhotplate-based conductance type gas sensor system is described. A bulk micromachining technique is used to create suspended microhotplate structures. The thermal properties of the microhotplates include a one-millisecond thermal time

Large Area, Ultra-high Voltage 4H-SiC PiN Rectifiers

December 1, 2002
Author(s)
Ranbir Singh, Kenneth G. Irvine, D C. Capell, James Richmond, David W. Berning, Allen R. Hefner Jr., John W. Palmour
This paper reports the design, fabrication, and high temperature characteristics of 1 mm 2, 4 mm 2, and 9 mm 2 4H-SiC rectifiers with 6 kV, 5 kV, and 10 kV blocking voltage respectively. These results were obtained from two lots in an effort to increase

Monte Carlo Simulation of Noise Parameter Uncertainties

November 1, 2002
Author(s)
James P. Randa, Wojciech Wiatr
We present results for uncertainties in noise-parameter measurements, obtained using a Monte Carlo simulation of the measurements. Sets of data were generated to simulate measurements on a low-noise amplifier, with given uncertainties in the underlying

Thermal Component Models for Electro-Thermal Analysis of Multichip Power Modules

October 24, 2002
Author(s)
J J. Rodriguez, John V. Reichl, Zharadeen R. Parrilla, Allen R. Hefner Jr., David W. Berning, M Velez-Reyes, Jih-Sheng Lai
Thermal component models are developed for multi-chip IGBT power electronic modules (PEM) and associated high-power converter heatsinks. The models are implemented in SABER and are combined with the electro-thermal IGBT and diode models to simulate the
Displaying 426 - 450 of 718