Microwave Icing Sensor Based on Interdigital-Complementary Split-Ring Resonator

Icing has always been a problem for the aviation industry and the UAV sector. Small and accurate icing sensors can ensure the safety of critical parts of the aircraft and small UAVs in flight. This paper presents an Interdigital-complementary split-ring resonator sensor (ICSRR) that can distinguish water and ice with high accuracy and measure the thickness of ice. Compared with the traditional CSRR structure, the added Interdigital structure can measure ice thickness more sensitively. The sensor detects water and ice based on the change in resonant frequency measured in the scattering parameter S21 coefficient. A prototype sensor was built, and measurements were taken to verify the functionality of the sensor. First, the resonant frequencies under no-load were measured. Second, the process of water icing was characterized using the sensor. Finally, the accuracy of the sensor's measurement of icing thickness was verified, and the data were fitted. The experimental results show that it is feasible to use the ICSRR sensor to monitor the icing condition and ice thickness.