MICROWAVE DIELECTRIC-PROPERTIES OF PLANT MATERIALS
MICROWAVE DIELECTRIC-PROPERTIES OF PLANT MATERIALS
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DOI：
10.1109/tgrs.1984.350644
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发表时间：
1984-01-01
影响因子：
8.2
通讯作者：
JEDLICKA, RP
中科院分区：
文献类型：
--
作者：
ULABY, FT;JEDLICKA, RP
采用1-2 GHz、3.5-6.5 GHz和7.5-8.5 GHz三种波导传输系统，测量了植被材料的介电特性随含水率和微波频率的变化规律。测量的材料主要包括玉米和小麦的叶子和茎秆。用机械方法从植被中提取植物材料中所含的液体，对其进行介电测量。萃取液的等效NaCl盐度约为10 / mil，这对频率低于5 GHz的介质损耗有显著影响。讨论了用介电常数及其组成部分（即大块植被、空气、束缚水和自由水）的体积分数来模拟植被-水混合物介电常数的尝试结果。此外，给出了10.2 GHz玉米冠层和大豆冠层总衰减的时间变化测量结果。
Three waveguide transmission systems covering the 1-2, 3.5-6.5, and 7.5-8.5 GHz bands were used to measure the dielectric properties of vegetation material as a function of moisture content and microwave frequency. The materials measured included, primarily, the leaves and stalks of corn and wheat. Dielectric measurements also were made of the liquid included in the vegetation material after it was extracted from the vegetation by mechanical means. The extracted liquids were found to have an equivalent NaCl salinity of about 10 per mil, which can have a significant effect on the dielectric loss at frequencies below 5 GHz. The results of attempts to model the dielectric constant of the vegetation-water mixture in terms of the dielectric constants and volume fractions of its constituent parts (i. e., bulk vegetation, air, bound water, and free water) are discussed. Additionally, measurements of the temporal variations in the total attenuation at 10.2 GHz are presented for a corn canopy and a soybean canopy.