Publications

Displaying 1 - 25 of 190

Detailed Study of Uncertainties in On-Wafer Transistor Noise-Parameter Measurements

October 24, 2016

Author(s)

James P. Randa

This paper uses a Monte Carlo simulation program to explore various aspects of uncertainties associated with the measurement of the noise parameters of transistors on wafers. The dependence of the noise-parameter uncertainties on the different input

Numerical Modelling and the Uncertainty Analysis of Transistor Noise-Parameter Measurements

December 5, 2014

Author(s)

James P. Randa

This paper provides an overview of the use of noise parameters as a numerical model to represent the noise characteristics of transistors, particularly in the context of a Monte Carlo evaluation of the uncertainties in noise-parameter measurements. The

Comparison of Noise-Parameter Measurement Strategies: Simulation Results for Amplifiers

December 4, 2014

Author(s)

James P. Randa

A previously developed simulator for noise-parameter measurements has been used in an extensive investigation and comparison of different measurement strategies for measuring the noise parameters of low-noise amplifiers (LNAs). this paper summarizes the

Amplifier and Transistor Noise-Parameter Measurements

October 1, 2014

Author(s)

James P. Randa

Methods for measuring the noise parameters of amplifiers and on-wafer transistors are reviewed. After some preliminary background information and conventions, noise parameters are defined and the most common measurement strategies are presented, both for

A Geometric Error Model for Misaligned Calibration Target in Passive Microwave Remote-Sensing Systems

November 1, 2013

Author(s)

Dazhen Gu, James P. Randa, Dave K. Walker

We present a geometric error model associated with calibration-target misalignment in passive microwave remote-sensing systems. The developed analytic formulation is universally applicable to both lateral and rotational misalignment conditions. Numerical

A Geometric Error Model for Misaligned Calibration Target in Passive Microwave Remote-Sensing Systems

May 29, 2013

Author(s)

Dazhen Gu, James P. Randa, Dave K. Walker

We present an error model associated with calibration-target misalignment in microwae remote sensing systems. The developed analytic formulation is universally applicable to both lateral and rotational misalignment conditions. Simultations are performed on

Measurement and uncertainty analysis of a cryogenic low-noise amplifier with noise temperature below 2 K

May 1, 2013

Author(s)

Dazhen Gu, James P. Randa, Robert L. Billinger, Dave K. Walker

We report a record low noise temperature (NT) measured on a cryogenic low-noise amplifier (LNA) at the National Institute of Standards and Technology (NIST). The LNA exhibits about 44 dB gain and less than 2 K average NT in its operational band

A Verification Method for Noise-Temperature Measurements on Cryogenic Low-Noise Amplifier

December 31, 2012

Author(s)

Dazhen Gu, James P. Randa, Robert L. Billinger, Dave K. Walker

We report a verification method for noise-temperature (NT) measurements on cryogenic low-noise amplifiers (LNAs) at liquid helium temperature. The method uses a comparison between the individual measurements of the LNA and an attenuator and the joint

An Investigation of Antenna Characterization Techniques in Microwave Remote Sensing Calibrations

July 22, 2012

Author(s)

Derek A. Houtz, Dazhen Gu, Dave K. Walker, James P. Randa

We compare three methods of quantifying illumination efficiency (IE). The ratio IE describes the contribution of energy emitted from a blackbody target to the total energy measured at an antenna aperture in a free-space microwave calibration target

Realization of a Standard Radiometer for Microwave Brightness-Temperature Measurements Traceable to Fundamental Noise Standards

July 22, 2012

Author(s)

Dazhen Gu, Derek A. Houtz, James P. Randa, Dave K. Walker

We describe and demonstrate a standard radiometer for making microwave brightness-temperature measurements that are traceable to fundamental noise standards. The standard radiometer is based on a National Institute of Standards and Technology (NIST)

A Verification Method for Noise-Temperature Measurements on Cryogenic Low-Noise Amplifiers

July 1, 2012

Author(s)

Dazhen Gu, James P. Randa, Robert L. Billinger, Dave K. Walker

We report a verification method for noise-temperature(NT) measurements on cryogenic low-noise amplifiers (LNAs) at liquid helium temperature. The method uses a comparison between the individual measurements of the LNA and an attenuator and the joint

A Verification Method for Noise-Temperature Measurements on Cryogenic Low-Noise Amplifiers

July 1, 2012

Author(s)

Dazhen Gu, Derek A. Houtz, James P. Randa, Dave K. Walker

We report a verification method for noise-temperature (NT) measurements on cryogenic low noise amplifiers (LNAs) at liquid helium temperature. The method uses the comparison between the individual measurements of the LNA and an attenuator and the joint

Extraction of Illumination Efficiency by Solely Radiometric Measurements for Improved Brightness-Temperature Characterization of Microwave Blackbody Target

May 16, 2012

Author(s)

Dazhen Gu, Derek A. Houtz, James P. Randa, Dave K. Walker

We report our recent progress towards the deveopment of microwave brightness-temperature (BT) standards. As one of the crucial parameters, the antenna beam efficiencey (BE) was traditionally determined by the relative antenna pattern. We propose a

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