Typical Surface Features Microwave Dielectric Properties Of Experimental Research

Global observation by remote sensing is one of the most important instruments to obtain earth resources and environmental information in 21st century. Also, it is one of the eight big strategic subjects on which our country emphasise in the eleventh five-year plan. As a unique and effective burgeoning remote sensing instrument, Microwave remote sensing is getting more and more recognition from all big spaceflight countries. With the rapid development of microwave remote sensing data sources from planes and satellites, as well as the improvement of the quality of data, how to extract the variety of useful information from those data becomes the most significant research work of microwave remote sensing application.Researching on the dielectric characteristic of the typical ground objects at microwave frequencies is main part of microwave scattering principle research, and it is also the base for building the microwave remote sensing backscattering model and inversing the electromagnetic parameters. Therefore, this paper mainly focuses on the research of the dielectric characteristic of the typical ground objects at microwave frequencies by both of theory and experiments. First of all, the conventional methods of microwave remote sensing are summarized systematically. And then it builds the overall framework of researching on the electromagnetic parameters gained by remote sensing. Based on the framework, a series of studies are conducted.In the study, theoretical analysis is always closely connected with experimental measurement. At first, it introduces all kinds of dielectric models of the typical ground objects such as pure water, salt water, sea water, soil, plant and so on. And then the model is simulated by computing quantitative relationship of their dielectric constant, frequency, temperature, salinity, and humidity. In addition, measurements on the dielectric constant by both of the coaxial probe method and the waveguide method are made, the results of which are compared to that of simulation.In this paper, studies mainly focus on the research of the free-space method used to measure the macroscopical dielectric constant of large area of earth substances, due to the consistency of the scattering parameter obtained by indoor scattering measurement system and the microwave remote sensing scattering coefficient. Firstly, measurements on the scattering coefficients of ground objects are made in different wave bands and different incidence angles. Secondly, the dielectric constant is inversed. Thirdly, after analyzing the cause of the experimental error detailedly, the indoor scattering measurement system and measurement method are improved, and the results are accord with the results of simulation. Finally, the measurement results are corrected at the high frequencies, using the roughness correction model, which reduces the influence of geometric characteristics of objects and improves the results of dielectric constant inversion.Finally, this paper makes measurements indoor on the backscattering coefficients of soil at different frequency bands. And also it analyzes these measurement data and inverses them. What's more, some new experimental methods and inversion methods are discussed, which is the groundwork for deeply researching on the microwave remote sensing principle.