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Measurement of dielectric properties in the frequency range of 300 Mhz to 3 Ghz as a function of temperature and density.

Authors
Salsman-JB
Source
Ceramic Trans 1991 Sep; 21:203-214
NIOSHTIC No.
10011032
Abstract
The U.S. Bureau of Mines has conducted an extensive research program on identifying those properties of minerals that are affected by microwave energy, namely the dielectric constant and loss tangent. The objective was to establish a reliable data base for predicting the effects of microwave heating on minerals. The dielectric constant and loss tangent of minerals, commonly referred to as the dielectric properties, were determined utilizing the theory of microwave propagation through an open-ended air-filled coaxial line that was terminated at its open end with the particular mineral under investigation and measuring the reflection coefficient of the mineral with a network analyzer. From the measured values of the reflection coefficient, the dielectric properties of the mineral could be determined. The dielectric properties of powdered minerals with medium to high electrical conductivities (tan8 >/= 0.01) Were measured in the frequency range of 300 mhz to 3 ghz. Techniques were used to relate the measured dielectric properties of the powdered minerals to the dielectric properties of the mineral at its theoretical or natural density. Also, these measurements were performed as a function of temperature, from 25 to 325 deg c. The results of the dielectric constants and loss tangents using this method were determined to be precise within +/-5 pct. This report describes the method of measurement and discusses the results of the Bureau's investigations into dielectric properties of minerals with the inclusion of typical measured data.
Keywords
Mining-industry; Microwave-radiation; Minerals; Electric-properties; Electrical-properties
CODEN
CETREW
Publication Date
19910901
Document Type
OP; Journal Article
Editors
Clark-DE; Gac-FD; Sutton-WH
Fiscal Year
1991
NTIS Accession No.
NTIS Price
ISBN No.
9780944904435
Identifying No.
OP 242-91
ISSN
1042-1122
NIOSH Division
TURC
Source Name
Ceramic Transactions. Symposium on Microwaves: Theory and Application in Materials Processing, proceedings of the 93rd Annual Meeting of the American Ceramic Society, Cincinnati, Ohio, April 29-May 3, 1991
State
AL
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