A Study on Passive Imaging Method for Electromagnetic Radiation Sources

本研究项目的一个主要目标是从观测到的电磁场中定位和表征辐射源，即一次源或二次源。研究期间取得的成果总结如下：1.被动成像方法的理论研究：射频电路的电磁辐射主要产生在传输线的弯曲和电路的不连续部分。这些部分的电流可以用电偶极子或磁短偶极子来模拟。因此，实现了搜索位于任意区域的这些电磁辐射源的精确逆过程。为了说明这个概念，我们处理了一种高度理想化的情况，然而，分析是全波处理，反问题的解在数学上是精确的。实验研究：为了验证上述理论的有效性，使用位于x-y绘图仪上的两个环形天线和/或两个偶极子天线进行了实验。由上述理论合成的图像表明，天线的位置得到了很好的重建。

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.