In order to realize on-line monitoring on moisture content of solid substance

a non-contact substance moisture sensor using frequency domain reflect principle is designed.This sensor is designed based on the relation of solid substance moisture content and dielectric constant

using the testing ability of capacitive probe on dielectric constant

the math model between volumetric moisture content and dielectric constant is built up by moisture content variation experiment

the design of sensor structure and circuit is accomplished.The results of experiment indicate that the sensor realizes accurate measurement of solid substance moisture content

which meet requirment of substance moisture monitoring.