【摘要】 研究地物物质的辐射率和反射率,物质的介电常数是必要的参数。根据地物的特点及对各种测量方法的分析,决定采用终端短路线法,但在毫米波段,由于波导截面小,其样品长度的测量精度差,因而影响测量结果的精确性。故而对终端短路线法进行改进。本文用渐变波导的原理,将样品波导段的截面加大为毫米波段波导截面的九倍,从而提高了测量的精度。用此方法对于地物的毫米波段介电常数进行测量。测量结果与微波辐射率仪测出的结果进行比较,两者是符合的。更多还原

【Abstract】 The microwave dielectric constants are very importment parameters to study the reflectivity and the emissivity of the substance of earth surface. After the discussion of measurement method, the short circuited line method was used. It is convenient to measure the dielectric constants of the substance of earth surface. Owing to the cross section of millimeter waveguide is too small to measure accuratelly the dielectric constant, the short circuited line method, in millimeter wave band, must be improved. In order to make the measured results exact and more reliable, in this paper, a gradual change waveguide was inserted in the line of measurement. It made the cross section of the sample waveguide to enlarge 9 times. It is suitable for measuring the dielectric constant of the substance of earth surface in millimeter wave band. The experimental results of water, oil and soil were discussed. They were in agree with the theoretical prediction.更多还原