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Title: BROADBAND FREE-SPACE MICROWAVE WHEAT PERMITTIVITY MEASUREMENTS

Author
item Kraszewski, Andrzej
item TRABELSI, SAMIR - UNIVERSITY OF GEORGIA
item Nelson, Stuart

Submitted to: Electromagnetic Wave Interaction with Water and Moist Substances Proceeding
Publication Type: Proceedings
Publication Acceptance Date: 3/15/2001
Publication Date: N/A
Citation: N/A

Interpretive Summary: There is a need for more accurate on-line monitoring of moisture content and other quality factors of agricultural products such as cereal grains and oilseed crops. Microwave measurements of electrical properties of these materials, called dielectric properties or permittivity, have been shown to provide reliable moisture content and density information for these crops. The microwave measurements are adaptable to on-line sensing of moisture content and density and offer promise for reliable measurements of grains and seeds in combine harvesters and conveying equipment. Further research may show that other quality factors can also be determined instantaneously if broader frequency range data are studied. This paper reports an improved broadband measurement technique for obtaining reliable data and offers suggestions for developing data over even wider ranges of frequency, which might lay the groundwork for radio-frequency and microwave edielectric spectroscopy useful in agricultural product quality sensing tha would be of benefit to producers and consumers alike.

Technical Abstract: Certain improvements in the free-space measuring system, operating between 3 and 13 GHz, are presented and results for the relative permittivity measurements for five different kinds of wheat are given. These data agree well with those taken previously, although finding corresponding numbers for lower frequencies is difficult, as loss factor of grain is to a great extent governed by the ionic conductivity of the material the parameter which is dependent upon local growing conditions, season, variety of wheat, etc. For further research, to provide even more accurate data in a very broad frequency range for a given grain sample, use of time-domain techniques is suggested.