Two UBC research teams - one that designs microwave sensors and microelectronics systems, and another that investigates ice-repellent materials and extreme liquid repellency - joined to develop a sensor that could detect the precise moment when ice begins to form on a surface. The researchers say they chose to use microwave resonators due to their high sensitivity, low power, ease of fabrication, and planar profile.
Resonators detect water, frost, and ice based on the measured resonant frequency, amplitude, and quality factor variation in scattering parameter of the sensor. Such devices, say the researchers, could make it easier to detect and manage ice accumulation on aircraft, potentially preventing airline tragedies directly linked to icy airplane wings.
"The ice detection systems used today are quite rudimentary. For example, pilots visually detect ice on aircraft wings before de-icing in flight," says Assistant Professor Kevin Golovin, who runs the Okanagan Polymer Engineering Research and Applications Lab. "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."
Planar microwave resonator sensors are simple traces of metal deposited onto a plastic, say the researchers, yet they are mechanically robust, sensitive, and easy to fabricate.
"The sensors give a complete picture of the icing conditions on any surface, like an airplane wing," says Assistant Professor Mohammad Zarifi, head of UBCO's Microelectronics and Advanced Sensors Laboratory. "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."
As well as being able to detect frost or ice accumulation, say the researchers, the reverse is also possible, and the sensors can detect when ice is melted away during de-icing. And the sensitivity and precision of the sensors means the detection occurs in real time, potentially