A high-precision saltwater ice thickness and salinity detection method based on capacitive coupled planar microwave resonator

The formation of saltwater ice on a ship can result in damage to the safety of the crew and the ship itself. A capacitive coupled split-ring resonant sensor was employed to investigate the influence of thickness and salinity of saltwater and saltwater ice on the transmission scattering parameter signal of the sensor. The resonant amplitude of the signal exhibited a near linear relationship with the salinity of saltwater samples, increasing from −18.24 dB to −14.75 dB as the salinity increased from 0 % to 20 %. The resonant amplitude exhibited a significantly decrease of 20.28 dB with the salinity of saltwater ice increasing from 0 to 15 %, and would be relatively stable at around −21.72 dB when the salinity of saltwater ice increased above 10 %. The salinity would be more sensitively detected in saltwater ice than in saltwater in the range of 0–10 %, where the resonant amplitude decreased 20.28 dB as the salinity increased. The measurement accuracy for salinity detection in saltwater ice was 70.22 %. The thickness of saltwater ice was able to detected accurately in the range of 0–15 mm with an accuracy of 86.9 %. In conclusion, this work provides a reference for the detection of saltwater ice on ship hulls and offshore wind turbines, thereby improving the efficiency and safety of these offshore structures.