Date of Award

Spring 5-3-2024

Level of Access Assigned by Author

Open-Access Thesis

Degree Name

Master of Science (MS)

Department

Electrical and Computer Engineering

Advisor

Nuri Emanetoglu

Second Committee Member

Mauricio Pereira da Cunha

Third Committee Member

Donald Hummels

Abstract

This thesis explores the design, simulation, and validation of a high-temperature (HT) Colpitts oscillator, motivated by the need for robust electronics in HT harsh environments (HE) across sectors such as space exploration, power generation, and industrial processes. The Colpitts oscillator circuit utilizes a silicon carbide (SiC) MOSFET in a source follower amplifier and an LC resonant tank circuit. The circuit was assembled on an alumina board with gold traces using silk-screen printing, and 1mm gold bond wires were employed for component connections. The design and analysis of the oscillator, in both open and closed-loop configurations, involved deriving the transfer function from nodal equations, solved using MATLAB. Subsequently, simulations in Microcap assessed the oscillator’s output characteristics. Sensitivity analysis highlighted the circuit's response to component variations, especially noting the oscillation frequency's sensitivity to inductor and capacitor values. Additionally, Monte Carlo simulations in both Micro-cap and MATLAB assessed the circuit’s performance under varying temperatures and component tolerances. Three circuits, labeled Prototype #1, Alpha, and Beta, were fabricated, and tested inside a furnace, powered by either a conventional power supply or Thermoelectric Generators (TEGs). These circuits operated successfully from room temperature to 350°C, demonstrating wireless signal transmission capabilities with successful detection 11 feet away from the furnace, validating their potential for remote wireless sensing in HT industrial environments. However, performance instability at 400°C and discrepancies between simulated and experimental results indicate future research directions, including the development of more accurate circuit models, improvements in circuit layout, and the exploration of temperature-compensated designs for improved stability. Thus, this thesis contributes to the advancement of high-temperature electronics, paving the way for the deployment of reliable wireless sensing technologies in HT HE settings.

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