As the oil and gas industry continues to explore higher temperature environments, electronics that operate at those temperatures without additional cooling become critical. Additionally, current communications systems cannot support the higher data-rates being offered by advancements in sensor technology. An RF modem would be capable of supplying the necessary bandwidth to support the higher data-rate. A voltage-controlled oscillator is an essential part of an RF modem. This thesis presents a 2.336-2.402 GHz voltage-controlled oscillator constructed with 0.25 μm GaN-on-SiC technology high electron mobility transistor (HEMTs). The measured operating temperature range was from 25°C to 225°C. A minimum tuning range of 66 MHz, less than 20% variation in output power, and harmonics more than 20 dB down from the fundamental is observed. The phase noise is between -88 and -101 dBc/Hz at 100 kHz offset at 225°C. This is the highest frequency oscillator that operates simultaneously at high temperatures reported in literature. / Master of Science / The oil and gas industry require communications systems to transmit data collected from sensors in deep wells to the surface. However, the temperatures of these wells can be more than 210 °C. Traditional Silicon based circuits are unable to operate at these temperatures for a prolonged period. Advancements in wide bandgap (WBG) semiconductor devices enable entrance into this realm of high temperature electronics. One such WBG technology is Gallium Nitride (GaN) which offers simultaneous high temperature and high frequency performance. These properties make GaN an ideal technology for a high temperature RF modem. A voltage-controlled oscillator is an essential part of a RF modem. This thesis demonstrates a GaN-based 2.36 GHz voltage-controlled oscillator (VCO) whose performance has been measured over a temperature range of 25°C-225°C. This is the highest frequency oscillator that operates simultaneously at high temperatures reported in literature.
| Identifer | oai:union.ndltd.org:VTETD/oai:vtechworks.lib.vt.edu:10919/84935 |
| Date | 29 August 2018 |
| Creators | Turner, Nathan Isaac |
| Contributors | Electrical Engineering, Ha, Dong Sam, Yi, Yang, Baumann, William T. |
| Publisher | Virginia Tech |
| Source Sets | Virginia Tech Theses and Dissertation |
| Detected Language | English |
| Type | Thesis |
| Format | ETD, application/pdf |
| Rights | In Copyright, http://rightsstatements.org/vocab/InC/1.0/ |
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