Microwave ring resonator-based non-contact interface sensor for oil sands applications

This paper presents the design, fabrication, and characterization of a non-contact microwave resonator sensor for liquid-liquid interface detection. The core of this sensor is a microwave planar ring resonator tuned at 5.25 GHz with a Q factor of 180. The geometry and materials of the designed sensor were optimized for higher sensitivity by finite element modeling and simulations. Here we demonstrate the detection of different liquid-liquid interfaces such as water-olive oil, water-olive oil-ethanol, and rag layer samples using microwave resonator method. In the proposed sensor, the resonance frequency demonstrated a maximum variation of 5.7% for water to rag layer interface. To increase the accuracy of the sensor in the interface detection, quality factor is also measured and demonstrated a maximum variation of 85% depending on the materials. The proposed sensor provides a non-contact real time, cost-effective, robust method for interface detection, which has potential applications in the oil sands industry.