Accession Number : ADA111606

Title :   In-Situ Microwave Measurements of Lossy Dielectrics.

Descriptive Note : Final rept. 15 Sep 78-15 Jan 82,

Corporate Author : WISCONSIN UNIV-MADISON DEPT OF ELECTRICAL AND COMPUTER ENGINEERING

Personal Author(s) : King, R J ; Kim, C D ; Beyer, J B

PDF Url : ADA111606

Report Date : Jan 1982

Pagination or Media Count : 43

Abstract : The objective of this work has been to develop microwave (4.9 GHz) instrumentation systems, and measurement and inversion techniques for determining the complex dielectric constant of lossy media in-situ. Unique features of this work, compared to other studies, are that the complex propagation constants of traveling waves which are coupled to the medium under test are measured using phase-sensitive homodyne systems. An invasive method was studied wherein a small modulated scattering probe is inserted into a test hole in the medium, and the propagation constant of a spherically expanding wave originating outside the medium is measured. Results are given for portage sand vs moisture content. A non-invasive method uses an open-walled slotted rectangular waveguide laid directly on the surface to couple the traveling wave in the waveguide to the medium. The instrumentation and measurement techniques work quite well and results are given for several media, e.g., rock, concrete, sand, etc. A promising inversion method for finding the dielectric constant is presented, along with suggested improvements in the design of the traveling wave applicator and the detection instrumentation. (Author)

Descriptors :   *ELECTRICAL MEASUREMENT, *DIELECTRICS, *MICROWAVE EQUIPMENT, LOSSES, DIELECTRIC PROPERTIES, COMPLEX VARIABLES, REMOTE DETECTORS, TRAVELING WAVES, ELECTROMAGNETIC SCATTERING, MODULATION, SAND, MOISTURE CONTENT

Subject Categories : Electricity and Magnetism

Distribution Statement : APPROVED FOR PUBLIC RELEASE