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Full-Text Articles in Physics

Frequency Conversion Analysis Of Noise In Heterojunction Bipolar Transistor Oscillators Including Periodically Modulated Noise Sources , Bradley Allen Kramer Jan 1993

Frequency Conversion Analysis Of Noise In Heterojunction Bipolar Transistor Oscillators Including Periodically Modulated Noise Sources , Bradley Allen Kramer

Retrospective Theses and Dissertations

A procedure which may be used to analyze the noise characteristics of HBT oscillators is presented. A large signal model of a HBT is developed based largely on the Gummel-Poon transistor model. A new base-emitter diffusion capacitance model is also generated which shows improved accuracy over conventional bipolar transistor models in characterizing HBTs. The large signal characteristics of the oscillator are then established using a time domain simulator. Conversion matrix theory is applied to the large signal model to generate an equivalent linear oscillator model which accounts for all of the frequency conversion effects which occur due to circuit nonlinearities ...


Acoustically Driven Integrated Microstrip Antennas And Electromagnetic Radiation From Piezoelectric Devices , Charles Forrest Campbell Jan 1993

Acoustically Driven Integrated Microstrip Antennas And Electromagnetic Radiation From Piezoelectric Devices , Charles Forrest Campbell

Retrospective Theses and Dissertations

For a receiver system to be considered integrated, the antenna and electronics need to be fabricated on a single semiconductor wafer. To avoid EMI problems, the circuitry must somehow be shielded from the environment where the antenna resides. The required shielding may be accomplished by separating the antenna on one side of the wafer from the electronics on the other side with a conducting ground plane. Energy may be acoustically coupled from the antenna to the circuitry through the ground plane via thin film piezoelectric transducers on either side of the wafer. The radiating side of the wafer would then ...


Growth And Characterization Of Polysilicon Films Deposited By Reactive Plasma Beam Epitaxy , Behnam Moradi Jan 1993

Growth And Characterization Of Polysilicon Films Deposited By Reactive Plasma Beam Epitaxy , Behnam Moradi

Retrospective Theses and Dissertations

Polycrystalline silicon was deposited at low temperatures (400-550°C) by using a new technique, reactive plasma beam epitaxy. The technique consists of using an intense flux of hydrogen radicals, generated by an electron cyclotron resonance (ECR) source to promote nucleation and crystallinity at low temperatures. The film structure could be smoothly changed from polysilicon to amorphous by changing the flux of incoming H radicals on the surface of the sample. The flux of hydrogen radicals can be controlled by changing the deposition pressure, with lower pressures leading to a higher H radical flux and greater degree of crystallinity. The effect ...