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ARS Home » Research » Publications at this Location » Publication #115837
Title: USING MICROWAVE SENSORS FOR DETERMINING PHYSICAL PROPERTIES OF GRANULAR MATERIALS

Author
item TRABELSI, SAMIR - UNIVERSITY OF GEORGIA
item Nelson, Stuart
item RAMAHI, OMAR - COMPAQ COMPUTER CORP.

Submitted to: Institute of Electrical and Electronics Engineers
Publication Type: Abstract Only
Publication Acceptance Date: 9/30/2000
Publication Date: N/A
Citation: N/A

Interpretive Summary:

Technical Abstract: In many industries, such as agricultural, pharmaceutical and mining, nondestructive real-time sensing of physical properties of materials has become a necessity. Therefore, there is a real opportunity to develop a new generation of sensors that fulfills the requirements of highly automated industries Microwave techniques based on the extraction of the desired physical properties from measurements of their dielectric properties have shown promise for achieving such goals. Free-space measurements on corn, wheat, oats and soybeans were conducted at microwave frequencies between 2.5 and 12.3 GHz over wide ranges of temperature and at bulk density and moisture content ranges of practical interest. The data collected were analyzed to define optimum operating conditions for microwave moisture sensing in these granular materials. Particular emphasis was placed on defining a "universal" calibration method which allows moisture content to be determined regardless of kernel size, shape, and composition. Use of microstrip antennas is considered as sensing elements for a microwave moisture sensor for these materials. A three-dimensional Finite-Difference Time-Domain method is used to simulate numerically the wave-material interaction for a material with dielectric properties and physical characteristics similar to those measured for corn , wheat, oats, and soybeans. Results of the numerical simulation are compared to those obtained experimentally.