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United States Department of Agriculture

Agricultural Research Service

Research Project: SENSING METHODS & INSTRUMENTATION FOR RAPID DETERMINATION OF MOISTURE CONTENT... AND OTHER QUALITY ATTRIBUTES OF GRAINS, SEEDS, & NUTS

Location: Quality and Safety Assessment Research Unit

Title: Measuring the complex permittivity of poultry meat with a planar transmission-line sensor

Authors
item Roelvink, Jochem
item Trabelsi, Samir

Submitted to: Meeting Proceedings
Publication Type: Proceedings
Publication Acceptance Date: March 6, 2013
Publication Date: May 6, 2013
Citation: Roelvink, J.T., Trabelsi, S. 2013. Measuring the complex permittivity of poultry meat with a planar transmission-line sensor. Proceedings of the 2013 International Instrumentation and Measurement Technology Conference. p.1689-1693.

Interpretive Summary: Permittivities, or dielectric properties, of materials are electrical characteristics that determine how materials interact with electric fields such as those of high-frequency and microwave electromagnetic energy. Therefore, the dielectric properties of materials determine how rapidly they will heat in microwave ovens and lower radio-frequency dielectric heating equipment. Dielectric properties are also important in low power applications, such as the rapid measurement of moisture content in grain and other commodities and in sensing quality attributes of products that are correlated with their dielectric properties. Therefore it is often important to measure the dielectric properties of materials at the frequencies of interest in any application. In research on use of dielectric properties for sensing quality attributes of poultry meat, convenient and reliable means for measuring the permittivities of fresh chicken breast meat were required. A planar transmission-line sensor, consisting of two short lines of different length formed on a printed-circuit board, was evaluated for measuring the permittivity of chicken breast meat, at frequencies from 0.5 to 5 GHz, and results were compared with those obtained by a commercial coaxial probe for measuring dielectric properties at the same frequencies. The permittivities measured with the planar lines sensor exhibited less variation with sample orientation than were observed for the coaxial-probe measurements. This sensor can also be referred to as a coplanar waveguide sensor, since the two lines formed on the printed-circuit board are in the same plane, and the two transmission lnes are waveguides. The new coplanar waveguide sensor shows real promise for improving permittivity measurements, because it is more convenient to use and it samples a larger portion of the material being measured, thus giving better average permittivity data. It is therefore very useful in the continuing research to find useful correlations between dielectric properties of meat and other semisolid products and their quality factors. New rapid techniques for quality measurements are of benefit to producers, processors, marketers and the ultimate consumers of such products.

Technical Abstract: A planar transmission-line sensor is used to measure the complex permittivity of chicken breast meat over the frequency range 0.5 – 5 GHz. Results for the permittivity of nine samples of chicken breast meat are compared to results obtained with a commercially available open-ended coaxial-line probe. It is shown that there is generally less variation in the results obtained with the planar transmission-line sensor for different sample orientations.

Last Modified: 7/23/2014
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