Thesis (M.S.)--University of Wisconsin--Madison, 1984. / Typescript. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaf 103).

Thesis (Ph. D.)--University of Missouri-Columbia, 2007. / The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file. Title from title screen of research.pdf file (viewed on February 14, 2008) Vita. Includes bibliographical references.

The Gallium Arsenide Field Effect transistor (GaAs FET) is experiencing a widespread acceptance in space and terrestrial systems due to its low noise, high gain and frequency characteristics unmatched by bipolar devices. This paper describes a design of a 4 GHz low noise amplifier with GaAs FETs using the scattering parameters method. Special attention is given to overall noise/gain optimization in the band of interest. The Smith Chart is used extensively to match the two-port device with microstrip networks. Analysis and performance of the amplifier are presented.

Thesis (MScEng (Electrical and Electronic Engineering))--University of Stellenbosch, 2006. / Nonlinear transistor modeling is becoming increasingly popular due to the demand for high linearity and high efficiency microwave amplifiers. The available models often fail to accurately predict the higher order harmonics and intermodulation distortion, which are essential when designing high-linearity amplifier circuits. This thesis describes the design of hardware and software used for the development of nonlinear CAD models. A multiline TRL calibration kit is designed and manufactured so that the characterisation of a LDMOSFET, with a RF output power capability of 10W, can be performed using an adaptive-bias S-parameter measurement algorithm. Verification standards are also manufactured and used to determine the measurement accuracy after calibration. A series of GUIs are developed to ease the model extraction process. The extraction of the small-signal model parameters is performed between 0.4 and 3 GHz, and the extraction of the parameter values for the Fager large-signal model is then performed. An improved model is defined that implements two nonlinear charge sources in stead of the three nonlinear capacitors used in the Fager model. The nonlinear charge equations are formulated using the voltage-derivatives of the calculated nonlinear charge at each port of the device. By accurately modeling the voltagederivatives of the charge, where the voltages are functions of time, the prediction of the current produced by each of the charge sources is improved. The nonlinear models are verified against the MET model, and all three models are compared to measured data. It is shown that the models are able to accurately predict the single-tone and two-tone output harmonics for class-AB operation, and in many cases the predictions outperform that of the MET model. The single-tone output power is also verified for class-C operation. Although this prediction is not extremely accurate, it is found that the correct trend for the output harmonic power can be predicted.

Using the nonlinear Volterra series representation, analytical expressions for the third-order intermodulation distortion power and intercept point for a MESFET small-signal amplifier are derived when its equivalent circuit is bilateral and includes the gate-to-drain capacitance (CgJ explicitly as a nonlinear element. Previously developed analytical expressions treated Cgd as a linear element or incorporated it as part of gate-to-source and drainto- source capacitances (Cgs and Cds). These new analytical expressions are then compared with experimental data and good agreement is obtained. The analytical expressions are also used to study the variation of intermodulation distortion with input power, frequency, and source and load impedances. It is shown that the nonlinearity of Cgd contributes significantly to the intermodulation distortion power and the third-order intercept point and therefore should not be neglected in the analysis and design.

Thesis (M.S.)--University of Wyoming, 2007. / Title from PDF title page (viewed on July 28, 2008). Includes bibliographical references (p. 61-62).

Thesis (M.S.)--University of Missouri-Columbia, 2008. / The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file. Title from title screen of research.pdf file (viewed on August 14, 2009) Includes bibliographical references.

Dissertation (PhD)--University of Stellenbosch, 2007. / Bibliography. Also available via the Internet.

Made available in DSpace on 2014-10-09T12:34:37Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T14:00:48Z (GMT). No. of bitstreams: 0 / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / Tese (Doutoramento) / IPEN/T / Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP / FAPESP:08/05286-1

Made available in DSpace on 2014-10-09T12:34:37Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T14:00:48Z (GMT). No. of bitstreams: 0 / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / Este trabalho apresenta o desenvolvimento de uma plataforma para o estudo teórico e experimental de dispositivos amplificadores de micro-ondas do tipo válvula de ondas progressivas (TWT). A plataforma é composta por um modelo matemático e uma bancada de testes. O modelo matemático descreve a TWT como uma linha de transmissão acoplada a um feixe eletrônico unidimensional, onde as forças de carga espacial AC e DC são calculadas auto consistentemente, eliminando-se a necessidade de um cálculo separado para o fator de redução de carga espacial. O modelo matemático deu origem a dois códigos para a simulação da TWT. Ambos foram comparados com resultados experimentais e teóricos disponíveis na literatura especializada para uma pré-validação. O nível de concordância entre os presentes resultados e aqueles de referência foi acima de 90%, o que atendeu as expectativas de exatidão do modelo, tendo em vista que nem todos os parâmetros de entrada estavam disponíveis na referência. A bancada de testes construída é composta por uma TWT com banda de operação de 6,0 a 18 GHz e potência saturada máxima em torno de 55 dBm (316 W) em 13 GHz, um circuito de polarização para a mesma e a instrumentação necessária para a realização das medidas pertinentes aos amplificadores de potência. A TWT em questão foi caracterizada segundo seu comportamento mono-sinal e multi-sinal. As curvas de ganho e potência foram obtidas em função da frequência utilizando a voltagem de aceleração do feixe eletrônico e a potência de entrada como parâmetros. As curvas de transferência de potência, de fase e compressão de ganho foram obtidas para frequências escolhidas ao longo da banda, tendo novamente a voltagem de aceleração como parâmetro. Adicionalmente, a produção de produtos de intermodulação de terceira ordem foi caracterizada no ponto de 1 dB de compressão de ganho ao longo da banda analisada. Um teste de linearização por injeção de sinais, que estava previsto no plano de trabalho, não apresentou o desempenho esperado devido a problemas no funcionamento do circuito linearizador. Esses problemas foram analisados e listou-se uma série de passos para saná-los. / Tese (Doutoramento) / IPEN/T / Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP / FAPESP:08/05286-1