A Study on Passive Imaging Method for Electromagnetic Radiation Sources

该研究项目的主要目标是定位和表征辐射源，即，主要来源和/或次要来源，从观察到的电磁场。本研究取得的主要成果如下：1.无源成像方法的理论研究：射频电路的电磁辐射主要产生于传输线的弯曲和电路的不连续部分。这些部分的电流可以通过电或磁短偶极子来建模。因此，一个精确的逆过程中搜索这些电磁辐射源位于一个任意的区域。为了说明这个概念，我们处理了一个高度理想化的情况，然而，分析是一个全波处理，逆问题的解决方案是数学上精确的。实验研究：为了证实上述理论的有效性，使用两个环形天线和/或两个位于x-y轴上的偶极天线进行实验。由上述理论合成的结果图像显示天线的位置被很好地重建。

A main objective of this research project is to localize and characterize the radiating sources, i.e., the primary sources, and or the secondary sources, from observed electromagnetic field. The results obtained during the term of research are summarized as follows.1. Theoretical studies on passive imaging method : Electromagnetic radiation from a radio frequency circuit yields mainly at a bend of transmission line and a discontinuous portion of the circuit. The currents at these portions may be modeled by the electric or magnetic short dipoles. Therefore a exact inverse procedure for searching these electromagnetic radiation sources located in an arbitrary region was implemented. To illustrate the concept we dealt with a highly idealized situation, however, the analysis was a full-wave treatment, and the solution of the inverse problem was mathematically exact.2. Experimental studies : In order to confirm the validity of the above theory, an experiment was performed using two loop antennas and or two dipole antennas located on the x-y plotter. The resultant images synthesized by the above theory show the position of the antennas are well reconstructed.