U.S. flag

An official website of the United States government

Official websites use .gov
A .gov website belongs to an official government organization in the United States.

Secure .gov websites use HTTPS
A lock ( ) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.

Search Publications by: Dazhen Gu (Fed)

Search Title, Abstract, Conference, Citation, Keyword or Author
Displaying 76 - 100 of 142

Verification of Noise-Parameter Measurements and Uncertainties

November 1, 2011
Author(s)
James P. Randa, Dazhen Gu, Dave K. Walker
We propose and implement verification methods for measurements of noise parameters of amplifiers and transistors. Because the verification rests on the comparison of different measurement results, it also serves as a test of the uncertainties. The

High Frequency Characterization of Contact Resistance and Conductivity of Platinum Nanowires*

October 1, 2011
Author(s)
Kichul Kim, Paul Rice, Thomas M. Wallis, Dazhen Gu, SangHyun S. Lim, Atif A. Imtiaz, Pavel Kabos, Dejan Filipovic
Abstract— Individual platinum (Pt) nanowires (NWs) with 100 nm and 250 nm diameters, embedded in coplanar waveguide (CPW) structures are investigated. Three approaches for characterization of their contact resistance and conductivity at high frequencies

Reflectivity Study of Microwave Blackbody Targets

September 1, 2011
Author(s)
Dazhen Gu, Derek A. Houtz, James P. Randa, Dave K. Walker
We report on the characterization of blackbody target reflections as part of the recent progress on the development of brightness temperature standards for microwave remote sensing at the National Institute of Standards and Technology (NIST). The very low

Electrical Characterization of Photoconductive GaN Nanowire Devices from 50 MHz to 33 GHz

July 1, 2011
Author(s)
Thomas M. Wallis, Dazhen Gu, Atif A. Imtiaz, Pavel Kabos, Paul T. Blanchard, Norman A. Sanford, Kristine A. Bertness, Christpher Smith
The electrical response of two-port., photoconductive GaN nanowire devices was measured from 50 MHz to 33 GHz. The admittance of individual contacted nanowires showed an increase on the order of 10% throughout the measured frequency range after exposure to

Deembedding parasitic elements of GaN nanowire MESFETs by use of microwave measurements

June 3, 2011
Author(s)
Dazhen Gu, Thomas M. Wallis, Paul T. Blanchard, SangHyun S. Lim, Atif A. Imtiaz, Kristine A. Bertness, Norman A. Sanford, Pavel Kabos
We present a deembedding roadmap for extracting parasitic elements of a nanowire (NW) MESFET device from full two-port scattering-parameter measurements in the frequency range from 0.1 GHz to 25 GHz. The NW MESFET is integrated in a microwave coplanar

Influence of Periodic Patterning on the Magnetization Response of Micromagnetic Structures

March 29, 2011
Author(s)
SangHyun S. Lim, Thomas M. Wallis, Atif A. Imtiaz, Dazhen Gu, Thomas Cecil, Pavel Kabos, Pavol Krivoski
The magnetization dynamics of a single, patterned, thin-film Permalloy (Ni80Fe20, Py) elements embedded in a coplanar waveguide (CPW) are investigated. The anisotropic magnetoresistance (AMR) effect serves as the detection mechanism in current-modulated