A Study of the Theory and Measurements of the Microwave Emission Properties of Natural Materials

摘要

The first part of the report is a general review of techniques for measuring the dielectric constant of materials at frequencies in the millimeter and centimeter regions of the electromagnetic spectrum. The general survey shows that for the purpose of obtaining dielectric properties of in situ natural materials and laboratory measurements of natural materials, the reflection-polarization (ellipsometric) system is most practical and applicable. Following the review of various systems, SGC develops the relationship between dielectric constants and power reflection coefficients showing fundamental dependency of each of these parameters on the other. In the final section, the relationship of the dielectric constant to the physical conditions of snow is fully developed. In this section, SGC shows there is a unique dielectric constant for snow when the melt condition (free water content) and density are specified. Using this relation and the relationship between dielectric constant and Fresnel reflection coefficients, radiometric temperature, polarization, and angle of observation may be used to fully analyze snow from a remote platform. (Author)