Date of Award

Fall 2002

Document Type

Thesis

Degree Name

Master of Science (MS)

Department

Electrical & Computer Engineering

Program/Concentration

Electrical Engineering

Committee Director

Ravindra P. Joshi

Committee Member

Frederic D. McKenzie

Committee Member

Keith Williamson

Call Number for Print

Special Collections (LD4331.E55 C87 2002 )

Abstract

Metal Semiconductor Field Effect Transistors are at the heart of currently used microwave and millimeter-wave devices. CAD (Computer Aided Design) models for MESFET are used in the development and optimization of high-speed microwave devices. The increase in the chip density demands more accurate models. A distributed small signal model was developed for a GaAs MESFET account of the high frequency effects.

The lumped model of the MESFET is inadequate at frequencies where the wavelength of operation approaches device dimensions. This is because different regions in the device can experience different amplitudes and phases of the biasing signal. In this thesis, various modeling approaches from the existing literature were studied, and the sliced-FET approach was selected as a trade-off between computational intensity and rigorous accuracy. The elements in the sliced model have been calculated for a 300- micrometer gate-width FET using modeling equations from literature. The sliced-FET model was implemented in PSPICE, and an optimal number of slices for the model have been proposed. The frequency response of the sliced model then more accurately resembles the actual response of an actual device. Scattering parameter measurements of the lumped and the distributed models validate the model developed. The scope of further research including thermal models, models at different bias conditions, HEMT simulation work, and the development of large signal models has also been discussed.

Rights

In Copyright. URI: http://rightsstatements.org/vocab/InC/1.0/ This Item is protected by copyright and/or related rights. You are free to use this Item in any way that is permitted by the copyright and related rights legislation that applies to your use. For other uses you need to obtain permission from the rights-holder(s).

DOI

10.25777/yx92-fd88

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