基于微带天线的粮食水分含量检测研究

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.