Icing monitoring with thickness shear acoustic waves

Icing monitoring and ice detection are critical challenges across many industries where ice formation can severely degrade performance or compromise safety. Conventional ice-sensing approaches, such as those based on surface acoustic waves (SAWs), often suffer from limited selectivity, fast saturation, and slow or energy-consuming recovery. In this work, we propose the use of thickness-shear-mode bulk acoustic waves (TSM-AWs) as a selective and robust alternative for monitoring icing phenomena, ranging from frozen sessile droplets to ice accretion in near-real scenarios within aeronautical envelopes. The sensing platform consists of a LiNbO₃ plate activated through lateral-field-excitation electrodes and driven electronically by a Vector or Scalar Network Analyzer. This system reliably detects both freezing conditions and temperature variations. Tracking the evolution of the magnitude of the reflection coefficient, specifically, the resonance peak and shape and frequency of|S11| minimum, of a strongly shear-dominant mode provides a reliable means to characterize and extract both qualitative and quantitative information about icing processes. Finite-element simulations further elucidate the physical mechanisms governing the ice monitoring capabilities. These results position TSM AW devices as promising candidates for a new generation of simple, light-weight, highly sensitive, and robust acoustic wave icing sensors.