TUTORIAL T3 Moisture and Density Sensing in Granular Solids Through Microwave Dielectric Measurements Lecturers: Stuart Nelson and Samir Trabelsi, U. S. Department of Agriculture, Agricultural Research Service, Athens, Georgia, USA Omar Ramahi, University of Maryland, College Park, Maryland, USA Monday, 17 May 2004, 9:00AM-1:00PM
This Tutorial will include a discussion of general principles for sensing moisture content and bulk density in granular hygroscopic solids. Basic relationships between the permittivity or dielectric properties of granular and powdered solids and the permittivities of the solid materials will also be described, and experimentally tested dielectric mixture equations will be discussed. Calibration methods for microwave sensing of moisture content and bulk density in agricultural grain and seed will be presented that are based on the principles outlined and free-space measurements of the permittivities of these materials. Such methods are applicable to the development of practical sensors for industrial application. Principles of microstrip antennas for measurements on granular materials will be presented, since economical antennas will be needed for development of low-cost practical instruments that can utilize the advantages of microwave measurements for moisture and density determination in such materials. |