Title :
Coaxial dielectric sensor for cereal grains
Author :
Lawrence, Kurt C. ; Nelson, Stuart O. ; Bartley, Philip G., Jr.
Author_Institution :
Agric. Res. Center, US Dept. of Agric., Athens, GA, USA
Abstract :
A system for measuring the dielectric properties of cereal grains from 25 to 350 MHz with a coaxial sample holder is presented. A signal-flow graph model was used to determine the permittivity of several polar alcohols from the full two-port S-parameter measurements. The system was calibrated with measurements on air and decanol and verified with measurements on octanol, hexanol, and pentanol. The standard error for the polar alcohols used for verification was 2.3% for the dielectric constant and 7.6% for the dielectric loss factor. Although measurements were taken on static samples, the sample holder is designed to accommodate flowing grain
Keywords :
S-parameters; agriculture; calibration; dielectric loss measurement; electric sensing devices; measurement errors; organic compounds; permittivity measurement; signal flow graphs; 25 to 350 MHz; air; cereal grains; coaxial dielectric sensor; coaxial sample holder; decanol; dielectric constant; dielectric loss factor; dielectric properties; flowing grain; hexanol; pentanol; permittivity; polar alcohols; sample holder; signal-flow graph model; standard error; static samples; two-port S-parameter measurements; Coaxial components; Density measurement; Dielectric constant; Dielectric losses; Dielectric measurements; Microwave measurements; Microwave theory and techniques; Moisture measurement; Permittivity measurement; Radio frequency;
Conference_Titel :
Instrumentation and Measurement Technology Conference, 1998. IMTC/98. Conference Proceedings. IEEE
Conference_Location :
St. Paul, MN
Print_ISBN :
0-7803-4797-8
DOI :
10.1109/IMTC.1998.679847
