Electromagnetic waves and antennas above and below the surface of the earth
Electromagnetic waves and antennas above and below the surface of the earth
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DOI：
10.1029/rs014i002p00189
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发表时间：
1979-03
期刊：
影响因子：
1.6
通讯作者：
R. King
中科院分区：
文献类型：
--
作者：
R. King
本文简要地回顾了在地球存在下由无穷小偶极子产生的电磁场，特别是H。布雷默延伸导体中电流产生的场可以用在所占体积上的积分来表示，但只有在已知电流对大地性质的依赖性时，才有可能对其进行计算。这是真实的水平线天线非常接近地球时，无论是由本地电动势驱动时，作为一个散射体在入射场。这也是真实的水平天线在地球上不太接近表面。最有用的组件的辐射或散射场的表达式制定为一个端部驱动的饮料型天线，水平线作为一个散射体在地球的存在下，和嵌入式绝缘行波天线。
The well-known electromagnetic fields generated by infinitesimal dipoles in the presence of the earth are reviewed briefly with special reference to contributions by H. Bremmer. The fields due to currents in extended conductors can be expressed in terms of an integral over the occupied volume but its evaluation is possible only when the currents are known in their dependence on the properties of the earth. This is true of the horizontal-wire antenna quite close to the earth both when driven by a localized emf and when acting as a scatterer in an incident field. It is also true of horizontal antennas in the earth not too close to the surface. Expressions for the most useful component of the radiated or scattered field are formulated for an end-driven Beverage-type antenna, for the horizontal wire as a scatterer in the presence of the earth, and for the embedded insulated traveling-wave antenna.