基于双二极管调制的边缘电场土壤水分传感器特性

研究了一种用于土壤水分测量的边缘电场平面传感器,设计了平面电容土壤水分传感器的双T二极管调制检测电路和数据处理系统,通过参数优化得到一种能够实现在线测试的土壤水分平面传感器及检测装置｡试验表明,随着土壤含水量的变化,传感器的响应有较大的变化,且在低于25%的含水量范围内,土壤含水量与被测电压之间近似线性关系,这种平面型土壤水分传感器在农业种植方面展示了广阔的应用前景｡ 
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Performance of Fringing Field Soil Water Content Sensor Basedon Dual Diodes Modulation

HU Jian-dong1,ZHAO Xiang-song1,WU Jian-zhong2,JIANG Min1,SHI Jian-hua2

(1.Henan Agricultural University, Zhengzhou 450002,China;2.Henan Nongda Xunjie Measuring Technology Co., Ltd., Zhengzhou 450002,China)

Abstract: A fringing field sensor for sensing soil sample water content was introduced. A kind of modulating circuit and data acquisition system were designed for these applications. The system is able to perform real-time capacitance measurements, and process the data to obtain parameters of interest. Experimental data demonstrates good sensitivity to parameter variation, nd a nearly linear dependency is observed between water content and the measured sample voltage when the soil water content is below 25%.Experimental results indicate the feasibility for broad application of this technique in the agricultural plant.

Key words: fringing field sensor; soil sample; planar capacitance