Typical Surface Features Microwave Dielectric Properties Of Its Indoor Measurement Method

As an important method to obtain the earth resources and environmental information, microwave remote sensing makes a fast development because of its effectiveness and unique. Microwave remote sensing mechanism researches on how to extract the effective feature information from the large amount of microwave remote sensing data, which is significant. Research on the dielectric properties of earth substances is one of the main elements of microwave scattering mechanism, and also it is the basis for the microwave remote sensing backscattering model and electromagnetic parameters inversion. In this study, the theoretical analysis closely combines with experimental measurements, in order to research on the dielectric properties of typical substances on earth, including indoor measurement systems and methods, theoretical dielectric models and experimental analysis.First of all, a series of algorithms are improved based on the need of microwave remote sensing application and the problems existing in the traditional waveguide transmission/reflection (TR) method, including coaxial-waveguide calibration, position error correction, three equations calculation, gap error correction and sample-box analysis method. Then, based on the improved waveguide TR method, the user interface software is developed using the National Instruments LabVIEW8.2, providing users the friendly operation interface. The improved method can more accurately and conveniently measure the dielectric properties of earth substances especially the low-loss solid materials, such as ice, soil and vegetations, providing the experimental platform for researching on the dielectric properties and backscattering models of the typical substances on earth.In addition, the coaxial probe method and the free-space method are introduced in this paper, in which their measurement principles and their own advantages and disadvantages are analyzed. The coaxial probe method can accurlately measure the liquid materials and conduct a large-range frequencies measurement. The free-space method can measure the materials without damage. Both of them can be compared to the waveguide method and verify the accuracy with each other, so that the dielectric properties of the earch substances can be studied comprehensively and accurately.Finally, the dielectric properties of the typical substances are researched at microwave frequencies, including pure ice, pure water, salt water, sea water, soil. On the one hand, their theoretical dielectic models are researched. On the other hand, their dielectric properties are made an analysis from the large amount of emperimental data. The relationship of the dielectric constants of the earth substances with frequencies, temperatures, compositions is analyzed, which makes a significant basis for researching on the scattering characteristics and building the backscattering models of the typical substances on earth.