基于微带天线的粮食水分含量检测研究

Research of Moisture Content Measurement of Grains Based on Microstrip Antennas

粮食含水量在作物生产、交通运输和谷仓存储等环节中均为重要的检测参量。微波能穿透被检测对象,与其内部水分子相互作用,将水分含量转换为散射参数的变化,从而测定材料中的水分含量。本文以大米作为检测对象,设计并加工了一款微带贴片式天线,实现了非接触、实时、高精度的含水量检测。采用接触与非接触两种检测方式,研究了大米含水量、体密度、检测高度与谐振频率、回波损耗、相位的关系。所提出的微带天线的检测灵敏度按谐振频率、回波损耗、相位表征分别为600 kHz/%、0.149 dB/%和1100 kHz/%,检测最小平均相对误差分别为0.026%、0.083%和0.028%,表明该微带天线在粮食含水量检测方面具有特殊的优势,为粮食储存和运输过程中的含水量实时检测提供了重要参考。

Moisture content is an important detection index during production,transportation,and barn storage of grains.Microwave can penetrate the materials under test,interact with the inner water molecules,and measure the moisture content by converting it into the scattering-parameter variation.In this paper,a microstrip antenna is designed and fabricated to realize non-contact,real-time and high-precision moisture content detection in rice.Contact and non-contact ways are adopted to study the relationship of moisture content,volume density,and detection height with resonant frequency,return loss and phase.The detection sensitivity is characterized by resonance frequency,return loss and phase as 600 kHz/%,0.149 dB/%and 1100 kHz/%,and the corresponding minimum mean relative error is 0.026%,0.083%and 0.028%,respectively.The results indicate that the proposed microstrip antenna has the special advantage in moisture content detection and provides an important reference for real-time moisture monitoring in storage and transportation of grains.