In our social activity, it is necessary to accurately and rapidly evaluate the liquid properties of lubricating oil, hydraulic work oil, and other oil, in order to guarantee the performance of industrial machines. The purpose of this study is to realize non-invasive measurement of liquid materials by extending the permittivity estimation method using scattered microwaves, and to establish a novel method for diagnosing the degree of deterioration of liquid materials with pattern recognition. The validity and effectiveness of the proposed method has been verified using forcibly deteriorated oil samples.
Sugawara et al. (Thu,) studied this question.