Dr. Robert J. Trew Profile

Dr. Robert J. Trew

Alton and Mildred Lancaster Professor at North Carolina State Univ

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Publications (6)

Proceedings Article | 12 February 2009 Paper

Predicting the performance of a power amplifier using large-signal circuit simulations of an AlGaN/GaN HFET model

Griff Bilbro, Danqiong Hou, Hong Yin, Robert Trew

Proceedings Volume 7216, 721603 (2009) https://doi.org/10.1117/12.803348

KEYWORDS: Instrument modeling, Gallium nitride, Device simulation, Amplifiers, Performance modeling, Microwave radiation, Physics, Resistance, Heterojunctions, Measurement devices

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We have quantitatively modeled the conduction current and charge storage of an HFET in terms its physical dimensions and material properties. For DC or small-signal RF operation, no adjustable parameters are necessary to predict the terminal characteristics of the device. Linear performance measures such as small-signal gain and input admittance can be predicted directly from the geometric structure and material properties assumed for the device design. We have validated our model at low-frequency against experimental I-V measurements and against two-dimensional device simulations. We discuss our recent extension of our model to include a larger class of electron velocity-field curves. We also discuss the recent reformulation of our model to facilitate its implementation in commercial large-signal high-frequency circuit simulators. Large signal RF operation is more complex. First, the highest CW microwave power is fundamentally bounded by a brief, reversible channel breakdown in each RF cycle. Second, the highest experimental measurements of efficiency, power, or linearity always require harmonic load pull and possibly also harmonic source pull. Presently, our model accounts for these facts with an adjustable breakdown voltage and with adjustable load impedances and source impedances for the fundamental frequency and its harmonics. This has allowed us to validate our model for large signal RF conditions by simultaneously fitting experimental measurements of output power, gain, and power added efficiency of real devices. We show that the resulting model can be used to compare alternative device designs in terms of their large signal performance, such as their output power at 1dB gain compression or their third order intercept points. In addition, the model provides insight into new device physics features enabled by the unprecedented current and voltage levels of AlGaN/GaN HFETs, including non-ohmic resistance in the source access regions and partial depletion of the 2DEG in the drain access region.

Proceedings Article | 6 February 2008 Paper

Reliability modeling of high voltage AlGaN/GaN and GaAs field-effect transistors

R. Trew, Y. Liu, W. Kuang, G. Bilbro

Proceedings Volume 6894, 68941H (2008) https://doi.org/10.1117/12.764958

KEYWORDS: Reliability, Gallium arsenide, Data modeling, Electrodes, Semiconductors, Field effect transistors, Amplifiers, Transistors, Device simulation, Ka band

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Proceedings Article | 8 May 2006 Paper

An optically triggered I-RTD hybrid device for continous-wave generation of THz oscillations

Dwight Woolard, Weidong Zhang, Elliott Brown, Boris Gelmont, Robert Trew

Proceedings Volume 6212, 621207 (2006) https://doi.org/10.1117/12.665820

KEYWORDS: Gallium, Gallium antimonide, Oscillators, Indium gallium arsenide, Terahertz radiation, Diodes, Semiconductors, Interfaces, Chromium, Hybrid optics

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Proceedings Article | 18 May 2005 Paper

Terahertz-frequency quantum oscillator operating in the positive differential resistance region

Peiji Zhao, Dwight Woolard, Matthew Lasater, C. Kelley, Robert Trew

Proceedings Volume 5790, (2005) https://doi.org/10.1117/12.602727

KEYWORDS: Electrons, Oscillators, Resistance, Quantum wells, Gallium arsenide, Scattering, Diodes, Aluminum, Electromagnetism, Terahertz radiation

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Proceedings Article | 20 January 1994 Paper

BMDO/U.S. Army electronics and optical materials research program

Robert Trew, John Zavada

Proceedings Volume 2042, (1994) https://doi.org/10.1117/12.166299

KEYWORDS: Defense and security, Electronics, Missiles, Defense technologies, Laser development, Light emitting diodes, Semiconductor materials, Defense systems, Semiconductors

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Showing 5 of 6 publications

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