Interference Criterion for Coaxial-Fed Circular Dipole Array Antenna in a Borehole
Interference Criterion for Coaxial-Fed Circular Dipole Array Antenna in a Borehole
复制标题
DOI：
10.1109/tgrs.2011.2182517
复制
发表时间：
2012-03
影响因子：
8.2
通讯作者：
S. Ebihara;H. Hanaoka;T. Okumura;Y. Wada
中科院分区：
文献类型：
--
作者：
S. Ebihara;H. Hanaoka;T. Okumura;Y. Wada
本文提出了一种用于定向钻孔雷达的同轴馈电井中圆偶极子阵（CFCAB），并给出了CFCAB的设计方法。在CFCAB中，圆形偶极子阵列被布置在导电圆柱周围。当波入射到天线上时，我们可以将在天线处接收到的信号分成两个分量。一种是由波直接到达天线引起的，另一种是由波在导电圆柱上散射引起的。提出了一种量化导电圆柱对雷达测量影响的判据。我们在空气中和花岗岩中的实验结果来检验该准则的有效性。利用该准则，我们设计并建造了工作在200 MHz左右的CFCAB定向钻孔雷达系统。通过在花岗岩中的野外实验，证实了CFCAB可以在时频平面上估计出波的方向，达到了预期的效果。
In this paper, we propose a coaxial-fed circular dipole array in a borehole (CFCAB) for directional borehole radar and present a design method for the CFCAB. In the CFCAB, a circular dipole array is arranged around a conducting cylinder. When a wave is incident on the antenna, we may divide the signals received at the antenna into two components. One is caused by the waves arriving at the antenna directly, and the other is due to the waves scattered at the conducting cylinder. We proposed a criterion to quantify the influence of the conducting cylinder on the radar measurement. We show results of experiments in air and in granite to examine the validity of the criterion. Making use of the criterion, we designed and built the directional borehole radar system with the CFCAB working at around 200 MHz. Conducting the field experiments in granite, we confirmed that the CFCAB can estimate the directions of arrival waves on the time-frequency plane, as we expected with the criterion.