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Displaying 76 - 100 of 190

Precision Measurement Method for Cryogenic Amplifier Noise Temperatures Below 5 K

March 1, 2006
Author(s)
James P. Randa, Eyal Gerecht, Dazhen Gu, Robert L. Billinger
We report precision measurements of the effective input noise temperature of a cryogenic (liquid helium temperature) MMIC amplifier at the amplifier reference planes within the cryostat. A method is given for characterizing and removing the effect of the

INTER-LABORATORY COMPARISON OF NOISE-PARAMETER MEASUREMENTS ON CMOS DEVICES WITH 0.12 um GATE LENGTH

December 1, 2005
Author(s)
James P. Randa, Susan L. Sweeney, Tom McKay, Dave K. Walker, David R. Greenberg, Jon Tao, Judah Mendez, G. Ali Rezvani, John J. Pekarik
We present results of an interlaboratory comparison of S-parameter and noise-parameter measurements performed on 0.12 υm gate-length CMOS transistors. Copies of the same device were measured at three different laboratories (IBM, NIST, RFMD), and the

Errors Resulting From the Reflectivity of Calibration Targets

January 1, 2005
Author(s)
James P. Randa, Dave K. Walker, Robert L. Billinger, Amanda E. Cox
For a microwave total power radiometer, we consider the error introduced by neglecting the difference int he antenna reflection coefficient between when it views a distant scene and a nearby calibration target. An approximate expression is presented for

Standard Radiometers and Targets for Microwave Remote Sensing

September 24, 2004
Author(s)
James P. Randa, Amanda Cox, Dave K. Walker, Michael H. Francis, Katherine MacReynolds, Jeffrey R. Guerrieri
We describe the NIST effort to develop brightness-temperature standards for microwave and millimeter-wave frequencies. Results of preliminary measurements at 26 GHz are presented.

Errors due to the reflectivity of calibration targets

September 20, 2004
Author(s)
James P. Randa, Dave K. Walker, Amanda Cox, Robert L. Billinger
For a microwave total-power radiometer, we consider the error introduced by neglecting the difference in the antenna reflection coefficient between when it views a distant scene and when it views a nearby calibration target. An approximate expression is

Linking Microwave Remote Sensing Measurements to Fundamental Noise Standards

July 2, 2004
Author(s)
James P. Randa, Dave K. Walker, Michael H. Francis
We outline the formalism for linking microwave remote-sensing measurements to fundamental noise standards and estimate the achievable uncertainty. Plans for the development and use of standard radiometers for this purpose are presented.

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

Traceability for microwave remote-sensing radiometry

June 1, 2004
Author(s)
James P. Randa
A plan is presented for developing a standard for brightness temperature at microwave frequencies, as well as two different methods for transferring this standard to the microwave remote-sensing community. The standard will be based on existing NIST

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

Noise-Parameter Uncertainties: A Monte Carlo Simulation

October 1, 2002
Author(s)
James P. Randa
This paper reports the formulation and results of a Monte Carlo study of uncertainties in noise-parameter measurements. The simulator permits the computation of the dependence of the uncertainty in the noise parameters on uncertainties in the underlying

Simulations of Noise-Parameter Uncertainties

June 7, 2002
Author(s)
James P. Randa
This paper reports results for uncertainties obtained using a Monte Carlo simulation of noise-parameter measurements. The simulator permits the computation of the dependence of the uncertainty in the noise parameters on uncertainties in the underlying

Vector Corrected Noise Temperature Measurements

June 7, 2002
Author(s)
Mark H. Weatherspoon, Lawrence P. Dunleavy, Ali Boudiaf, James P. Randa
A new one-port noise temperature measurement technique is presented that uses receiver noise parameters for error correction. Improved accuracy in one-port noise temperature measurements made with commercial systems is demonstrated without using isolators
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