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ARS Home » Southeast Area » Athens, Georgia » U.S. National Poultry Research Center » Quality & Safety Assessment Research » Research » Publications at this Location » Publication #330271

Research Project: Rapid Assessment of Grain, Seed, and Nut Quality Attributes with Microwave Sensors

Location: Quality & Safety Assessment Research

Title: A Substrate Integrated Waveguide Sensor for Measurement of Dielectric Properties of Biomass Materials

Author
item MCKEOWN, MURAT - University Of Georgia
item SAKOL, JULRAT - US Department Of Agriculture (USDA)
item Trabelsi, Samir
item TOLLNER, ERNEST - University Of Georgia

Submitted to: American Society of Agricultural and Biological Engineers
Publication Type: Proceedings
Publication Acceptance Date: 6/10/2016
Publication Date: 7/17/2016
Citation: Mckeown, M.S., Sakol, J., Trabelsi, S., Tollner, E.W. 2016. A Substrate Integrated Waveguide Sensor for Measurement of Dielectric Properties of Biomass Materials. American Society of Agricultural and Biological Engineers. ASABE Paper No. 162461429, American Society of Agricultural and Biological Engineers, St. Joseph, MI, 2016.

Interpretive Summary: Biomass materials are a class of plant products that can be utilized as an alternative source of energy. Often they are combustible materials that are byproducts of other agricultural production operations. Sawdust from the milling of timber into lumber and associated products is one example. Sawdust can be pelletized for economy in transporting it to points of consumption. The moisture content of such products is important in the binding of the materials during pelleting and when preparing the pellets for combustion. It is also is important when materials need to be stored without deterioration in quality. Therefore, techniques for reliably and rapidly measuring moisture content are needed for use in the industry. Microwave sensing techniques have been shown useful in the sensing of moisture content in such materials, because the dielectric properties of the materials are highly correlated with moisture content. This paper describes experimental work in developing new microwave sensing techniques that may be useful in monitoring moisture content of such biomaterials. Flat coplanar waveguide sensors can be used for measurement of the dielectric properties of materials placed on these sensors or passing over them. Substrate integrated waveguide (SIW) sensors offer some advantages for such applications because they are cheap to produce and provide more adaptable aspects of planar circuits. Propagation characteristics are similar to waveguides with the design retaining many positive aspects of waveguide propagation such as high quality-factor, electromagnetic shielding, and high power handling capabilities. A substrate integrated waveguide sensor was designed, fabricated and tested for performance at frequencies between 2.0 and 4.0 GHz for determination of dielectric properties and moisture content of sawdust at different moisture contents. It was calibrated with liquid dielectrics of known dielectric properties and then tested for measurements on sawdust samples at six different moisture contents. The SIW sensor showed promise for determination of moisture content of sawdust, but further work is necessary on the sensor development for practical use. The development of this type of moisture sensor would benefit those in the biomass industry and consumers as well eventually.

Technical Abstract: Substrate integrated waveguide- based sensors balance the performance and well known design techniques of classical waveguides with the cheaper and more adaptable aspects of planar circuits. Propagation characteristics are similar to waveguides with the design retaining many positive aspects of waveguide propagation such as high quality-factor, electromagnetic shielding, and high power handling capabilities. A substrate integrated waveguide sensor was designed by removing a portion of the metal layer of a double-sided copper- clad circuit board to make a structure similar to a slotted waveguide antenna. Preliminary work has been performed to determine the feasibility of the design operating at frequencies between 2.0 and 4.0 GHz for determination of moisture content of sawdust. Results showed extraction of dielectric properties from the reflection coefficient could be achieved. In addition, dielectric properties of sawdust between 10.6% and 47.1% were determined.