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Displaying 851 - 875 of 1560

Phase Dependence in Radar Cross Section Measurements

September 1, 2001
Author(s)
Lorant A. Muth
A new measurement and analysis technique to isolate the background signals present in radar cross section measurements is presented. By definition the measured RCS of a target is independent of the measured phase, but it is not independent of the phase

High Q resonating cantilevers for in situ measurements of ferromagnetic films

August 24, 2001
Author(s)
John M. Moreland, T. J. Hubbard
We describe micro cantilevers developed for in-situ measurements of ultra-thin ferromagnetic films. The cantilevers are optimized for use in a resonating torque micro-balance magnetometer that measures the magnetic moment of thin films as they are being

Meander Delay Line Challenge Problem: A Comparison Using FDTD, FEM and MOM Techniques

August 13, 2001
Author(s)
Alpesh Bhobe, Christopher L. Holloway, Melinda Piket-May
Full wave finite-difference time-domain (FDTD) and a simplified 1D- finite-difference time-domain technique using the multi-conductor transmission line equations are applied to a delay line to determine its propagation characteristics. The output volatge

Analyzing Broadband Free-Field, Absorber Measurements

August 1, 2001
Author(s)
David R. Novotny, Robert T. Johnk, Arthur Ondrejka
We present and analyze a method for free-field evaluation of 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 the material

Dielectric and Conductor-Loss Characterization and Measurements on Electronic Packaging Materials

July 1, 2001
Author(s)
James R. Baker-Jarvis, Michael D. Janezic, Billy F. Riddle, Christopher L. Holloway, Nicholas Paulter, J Blendell
This is an overview of dielectric measurement methods and metrology on substrate materials used in electronic packaging. These substrates include low-temperature co-fired ceramic, high-temperature co-fired ceramic substrates, printed wiring board, and

High Frequency Measurements of CoFeHfO Thin Films

July 1, 2001
Author(s)
Stephen E. Russek, Pavel Kabos, Thomas J. Silva, Fred B. Mancoff, D Wang, Z. T. Qian, J. M. Daughton
High frequency measurements of the transverse susceptibility and damping constant of CoFeHfo thin films have been made over a frequency range of 0.1 GHz to 6 GHz as a function of film resistivity, thickness, and temperature. The films show relatively low

Micromechanical Torque Magnetometer for In Situ Thin-film Measurements

July 1, 2001
Author(s)
John M. Moreland, Albrecht Jander, James A. Beall, Pavel Kabos, Stephen E. Russek
We describe a new type of magnetometer based on a microelectromechanical system (MEMS) for in situ monitoring of magnetic film moment during the film deposition process. The magnetometer measured mechanical torque on a film as it is deposited onto a

Analytic Sampling-Circuit Model

June 1, 2001
Author(s)
Dylan F. Williams, Catherine A. Remley
Abstract: We develop analytic expressions for the impulse response and kickout pulses of a simple sampling circuit that incorporate the nonlinear junction capacitance of the sampling diode. We examine the effects of both the time-varying junction

Hysteresis in transport critical-current measurements of oxide superconductors

May 31, 2001
Author(s)
Loren F. Goodrich, Theodore C. Stauffer
We investigated magnetic hysteresis in transport critical-current (I c) measurement of Ag-matrix (B i,Pb) 2Sr 2Ca 2Cu 3O^10-x^ *Bi-2223) and AgMg-matrix Bi 2Sr 2CaCu 2O 8+X (Bi-2212) tapes. The effect of magnetic hysteresis on the measured critical current

A Method to Compare Vector Nonlinear Network Analyzers

May 1, 2001
Author(s)
Kate Remley, Donald C. DeGroot, Jeffrey Jargon, Kuldip Gupta
We address the difficult problem of determining measurement consistency between two vector nonlinear network analyzers, a new class of stimulus-response instruments that acquire multiharmonic waveform data instead of normalized network parameters. We

Calibrating Electro-Optic Sampling Systems

May 1, 2001
Author(s)
Dylan Williams, Paul D. Hale, Tracy S. Clement, Juanita M. Morgan
We apply frequency-domain impedance mismatch corrections to a temporal electro-optic sampling system. We identify and evaluate additional sources of measurement uncertainty. We use the system to characterize the magnitude and phase response of a

Effects of Nonlinear Diode Junction Capacitance on the Nose-to-Nose Calibration

May 1, 2001
Author(s)
Kate Remley, Dylan Williams, Donald C. DeGroot, Jan Verspecht, John Kerley
We examine the effects of nonlinear diode junction capacitance on the fundamental premise of the noise-to-nose calibration, that the kickout is identical in shape to the impulse response of the sampler. We offer a physical explanation for the error

Modal Cutoff in Coaxial Transmission Lines of Conical and Cylindrical Geometries

May 1, 2001
Author(s)
Claude Weil, Billy F. Riddle, David R. Novotny, Robert T. Johnk
We present numerical data on normalized cutoff wavelength versus cone half-angle for the first three higher-order TE ml modes, as well as four other modes of interest, in conical coaxial transmission lines (the co-conical line). These are given as a

Modeling Coplanar Waveguide Structrues Constructed of Ferromagnetic Metal

May 1, 2001
Author(s)
Nicholas Cramer, Dave K. Walker
We fabricate coplanar waveguide transmission lines with thin-film Fe o.2Ni o.8 conductors. These lines demonstrate a power attenuation of 10 dB/cm at ferromagnetic resonance frequencies of 5 to 10 GHz for applied magnetic fields less than 80 kA/m (1 kOe)
Displaying 851 - 875 of 1560