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Wiltshire, Benjamin Daniel

University of British Columbia

With the advent of smart sensors and the Internet of Things, improved real-time sensing and detection capabilities are required for modern applications. Microwave sensors were designed and integrated with titanium dioxide nanotube arrays for high-resolution detection of UV and visible light, as well as CO₂ gas. Sensing was done by tracking the scattering parameters (S₁₁ or S₂₁) of a resonator as they vary with environmental changes such as material introduction, phase change, and chemical or light absorption. New microwave resonator designs were investigated through simulation, fabrication, and experiment to determine effective strategies in improving sensitivity, accuracy, speed, and lifetime in a variety of applications. The main potential of this approach is to develop accurate, robust, and inexpensive sensors that use a unique, low frequency region of the electromagnetic spectrum wirelessly without the need to overcome or model contact resistance. First, design strategies were used for liquid characterization at long range by detecting the UV transmission properties of the liquid. Similarly, a high frequency resonator was developed to detect UV intensities as low as 2.7 μW/cm2 by using an active resonator and reducing the effect of humidity by targeting a higher relative frequency. Additionally, TiO₂ was later used as a supporting scaffold for a secondary material, cadmium sulfide, for visible light sensitivity and to enable selective targeted sensing. The aim of this thesis is to better understand the capabilities of TiO₂ integration with microwave resonators by employing state-of-the-art nanofabrication methods and microwave design strategies to extend the limits of sensing in the microwave region.

Text

2023-10-13

Attribution-NonCommercial-NoDerivatives 4.0 International

http://hdl.handle.net/2429/86170

Electrical Engineering

University of British Columbia

UBCO

http://creativecommons.org/licenses/by-nc-nd/4.0/