A moisture detection of single rice grains using a slim and small open-ended coaxial probe is presented. The coaxial probe is suitable for the nondestructive measurement of moisture values in the rice grains ranging from from 9.5% to 26%. Empirical polynomial models are developed to predict the gravimetric moisture content of rice based on measured reflection coefficients using a vector network analyzer. The relationship between the reflection coefficient and relative permittivity were also created using a regression method and expressed in a polynomial model, whose model coefficients were obtained by fitting the data from Finite Element-based simulation. Besides, the designed single rice grain sample holder and experimental set-up were shown. The measurement of single rice grains in this study is more precise compared to the measurement in conventional bulk rice grains, as the random air gap present in the bulk rice grains is excluded.

中文翻译：

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小型纤细同轴探头，用于单粒稻米水分感测

提出了使用细长的小型开放式同轴探头对单个米粒进行水分检测的方法。同轴探头适用于米粒中水分含量的无损测量，范围从9.5％到26％。开发了经验多项式模型，使用矢量网络分析仪根据测得的反射系数来预测大米的水分含量。还使用回归方法创建了反射系数和相对介电常数之间的关系，并用多项式模型表示，该模型的模型系数是通过拟合基于有限元模拟的数据获得的。此外，还展示了设计的单个稻谷样品架和实验装置。