二维介质柱的电磁成像研究

从体等效原理出发得到用介质柱介电参数表示的体等效电流，并得到一个积分方程组求解散射问题．利用变分原理，对此方程组求变分，并化为矩阵方程组，消去含介质柱内总场变化的项，得到散射场变化与介质柱介电参数变化之间关系的矩阵方程．即反演方程．用算例检验此法的反演精度、收敛性能、多目标反演能力、抗噪声性能及利用不完备测量散射信息反演目标的能力．结果表明，此法是一种实用性很强的二维介质柱电磁成像方法．

MICROWAVE IMAGING OF DIELECTRIC CYLINDER IN FREE SPACE

The equivalent volume current source was obtained by the principle of volume equivalence. It was written as a function of the cylinder's permittivity and conductivity.Then, a system of integral equations was obtained. The direct scattering problem can be solved by Galerkin's method from it. The system is then taken to variation and transformed into a system of matrix equations. After deleting the terms concerning the internal electric field, the relationship between the variation of the cylinder'sparameters and that of scattering field was derived. So the inversion equation was obtained. Several examples were given tO investigate the inversion accuracy,converging property, ability to invert complex profiles, tolerance and the inversion ability with incomplete information of this method. Numerical results show that it is a practical imaging algorithm.