基于驻波原理的短探针小麦茎水分传感器

摘要

A wheat stem moisture sensor was designed by standing wave ratio theory. The sensor probe has tow paralleled needles with 8 mm interval, which are 21 mm in length and 0.7 mm in diameter. Optimal length of the transmission line was 39 cm according to the experimental data. By comparing sensor output voltage and moisture content measured by oven drying method, we finally obtained the calibration equation for our wheat stem water content sensor. The sensor showed good stability, linearity and sensitivity, with a maximum deviation less than 3%, an average deviation of 1.126% and a standard deviation of 1.299%.%该文以小麦为研究对象,尝试利用驻波率原理,研究一种测量小麦茎含水率的方法.针对小麦茎的特点,设计了具有短探针结构的传感器,波导探头为长21 mm,间距8 mm,直径0.7 mm的平行双针结构.研究了同轴传输线长度对传感器性能的影响,确定其长度为39 cm,并验证了基于驻波率原理测量方法的可行性.试验结果表明,该文设计的传感器具有较好的稳定性、线性度及灵敏度.通过与烘干法对比研究,得出了针对小麦茎含水率的标定公式,测量误差最大不超过士3％,平均偏差为1.126％,标准偏差为1.299％.