A collaboration between two teams of researchers at the Okanagan School of Engineering, University of British Columbia (UBCO) might have led to breakthrough in enhancing airline safety. The two teams—one designing microwave sensors and microelectronics systems and the other investigating ice-repellent materials—has resulted in a new planar microwave resonator that makes it easier to detect and manage ice accumulation on aircraft.

According to UBCO, the researchers aimed to develop a sensor that could detect the precise moment when ice begins to form on a surface. The team of researchers: head of UBCO’s Microelectronics and Advanced Sensors Laboratory, Mohammad Zarifi; Assistant Professor Kevin Golovin; graduate student Benjamin Wiltshire and graduate student Kiara Mirshahidi; published their research findings in Sensors and Actuators B: Chemical.

Golovin, in a statement, said that as the current ice detection systems in use are rudimentary sensors with higher sensitivity needs to be developed to reduce human error. “For example, pilots visually detect ice on aircraft wings before de-icing in flight,” Golovin said in the statement. “And on the tarmac, certifying that the aircraft is free of ice after de-icing is also done by visual inspection, which is susceptible to human error and environmental changes.”

The research teams chose to use microwave resonators for their high sensitivity, low power, ease of fabrication, and planar profile, said Golovin. According to the researchers, the sensitivity and precision of the sensors means detection can occur in real-time, making ground and in-flight de-icing faster, cheaper and more efficient.

They also explained that planar microwave resonator sensors are mechanically robust and easy to fabricate. “The sensors give a complete picture of the icing conditions on any surface, like an airplane wing. They can detect when water hits the wing, track the phase transition from water to ice, and then measure the thickness of the ice as it grows, all without altering the aerodynamic profile of the wing.”

This is the first report on using microwave resonators to detect frost or ice accumulation, said Zarifi. The reverse is also possible, and the sensors can detect when ice is melted away during de-icing, he added.

“The resonator detected frost formation within seconds after the sensor was cooled below freezing,” said Wiltshire, the first author of the study. “It took about two minutes at -10C for the frost to become visible on the resonator with the naked eye—and that’s in one small area in ideal lab conditions. Imagine trying to detect ice over an entire wingspan during a blizzard.” Planar microwave resonator devices have recently demonstrated significant performance in sensing, monitoring and characterising solid, liquid and gaseous materials. However, research on the detection of ice and frost has not been undertaken until now, said Zarifi, despite the benefits of real-time, sensitive and robust ice detection for transportation and safety applications.