Dielectric Properties of Agricultural Properties and Their Use in Moisture Sensing and Other Applications

Historical interest in dielectric properties of agricultural products and definitions of dielectric terms and basic principles governing their influence on elelctromagnetic energy are presented briefly . The nature of dielectric properties variation with frequency, temperature , and product density is discussed, Graphical data on the dielectric properties of products are presented that illustrate the dependence of these properties on moisture content, frequency, temperature, and density. Applications microwave dielectric properties of agricultural products are cited that include radio-frequency (RF) and microwave heating for seed treatment, improvement of nutritional and keeping qualities of some products, and controlling insects in grain. Uses of dielectric properties for product quality measurement and the rapid determination of moisture content are described. Principle of moisture determination in bulk grain by RF and microwave measurements are briefly presented.