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David R. Novotny, Robert T. Johnk, Arthur Ondrejka
We present a method for evaluating broadband absorber in a non-ideal testing environment. Using broadband, short impulse TEM horns, a frequency-rich spectrum (equivalent pulse length 0.5 ns) illuminates a sample of material under test and the reflections
This is a report on work in progress to understand the wide variations in sphere calibration data observed on dynamic radar cross section measurement ranges. The magnitude of these fluctuations indicate an uncertainty of greater than 2 dB in some cases
This paper examines broadband measurement techniques for electrical properties of planar transmission lines built on lossy silicon substrates. We start by investigating the performance of a new formulation of the calibration com-parison method which is
Following an initiative from the French and the U.S. National Committees, the IEC Technical Committee TC77 charged its Subcommittee 77A (Low-Frequency Phenomena) with the development of a new standard on the measurement of power quality parameters. The
A sensitive, directional coupling sensor attached to a highvoltage power transmission cable couples enough signal from a partial discharge to an electrooptic modulator to measurably change the amplitude of an optical carrier. The demonstrated sensitivity
The proliferation of surge-protective devices and switch-mode power supplies has radically changed the surge environment in low-voltage AC mains. Monitoring surge voltages has lost significance and can be misleading. Instead, surge currents should be
Stephen E. Russek, Terry J. Gaffron, S. L. Burkett
As spin valve technology evolves, understanding the limitations and design constraints is a critical consideration. Choosing the correct materials combination, aspect ratio and size depends upon careful device characterization. Analysis of spin valves in
We model a lightning return stroke by a vertical traveling wave of current with a complex propagation constant. The Sommerfeld-integral analysis is similar to that of a vertical electric dipole over a lossy earth except that the source is distributed in
Pavel Kabos, Shehzaad F. Kaka, Stephen E. Russek, Thomas J. Silva
Large angle rotations were studied in Permalloy thin films and spin valve devices. It is shown that edge effects or inhomogeneities strongly influence the magnetization behavior under certain initial conditions. Complicated intermediate states can form
John M. Moreland, Pavel Kabos, Albrecht Jander, M. Loehndorf, Robert McMichael, C G. Lee
We demonstrate micromechanical detection of ferromagnetic resonance (FMR) in thin magnetic films. FMR spectroscopy is performed on nanometer scale samples integrated with a micromachined silicon cantilever. We present several techniques by which the FMR
Simplifications often made when simulating the dispersion of lightning current can yield results that depart too much from the complex reality of a direct lightning flash to a building. The unpredictable occurrence of side-flashes increases even more the
T. S. Key, D. Nastasi, K. O. Phipps, Francois D. Martzloff
Lightning related damage stories abound, but it is not always possible to document precisely the mechanisms and scenarios involved when timely, first-hand knowledge is not obtainable. From a collection of case histories accumulated by the authors, three
Progress report on the restructuring of two IEEE standards concerned with surges in low-voltage a.c. power circuits into a Trilogy of three documents. First a basic Guide describes the surge environment, then a Recommended Practice proposes a limited set
Robert T. Johnk, David R. Novotny, Claude Weil, H. W. Medley
This paper summarizes a recent measurement effort by NIST researchers at an open-area test site (OATS), operated by a large information technology equipment manufacturer. The purpose of this effort was to assess the effects on emissions measurements of a
John M. Moreland, M. Loehndorf, Pavel Kabos, Robert McMichael
We describe a new type of ferromagnetic resonance (FMR) spectroscopy that is based on a calorimeter sensor. We use an atomic force microscopy cantilever coated with a ferromagnetic thin film as a bimaterial sensor to measure absorption of microwaves at 9
An axially-layered cylindrical dielectric resonator comprised of substrate and thin film is placed into a parallel plate waveguide and operated in axi-symmetric TE 0γŅ resonant mode structure for microwave dielectric thin film characterization. With this
We present three tests for evaluating the agreement between measurements taken in a reverberation chamber and the expected results given by simple statistical models. We then apply these tests to a chamber that is known to be sub-optimal. We also give
E Bray, John (Jack) W. Ekin, Cameron C. Clickner, L J. Masur
We have measured the effect of transverse compressive stress on the critical current of two similar sets of Bi 2Sr 2Ca 2Cu 3O X (Bi-2223) tapes in a direct comparison between tapes reinforced with pure Ag and oxide-dispersion-strengthened (ODS) Ag. The
Donald C. DeGroot, Paul D. Hale, M. Vanden Bossche, F. Verbeyst, Jan Verspecht
We analyze the input networks of the samplers used in the nose-to-nose calibration method. Our model demonstrates that the required input network conditions are satisfied in this method and shows the interconnection errors are limited to measurement
We develop a novel four-port equivalent circuit for a coplanar-waveguide-to-microstrip transition using a finite-difference time-domain analysis. The lumped model accounts for mutual inductive coupling and works well up to about 30 GHz.
This report presents the theory for near-field detection of quasi-static electric fields produced by electrically small emitters that radiate as small electric dipoles. The intended application is the detection of electronic timers of the type that could