Error analysis of the discrete complex image method and pole extraction

Recently, Teo et al (IEEE AP-S Int. Symp., vol. 4, pp. 862-864, 2001) proposed a discrete complex image method that is able to represent both the near and far fields of the Green's function accurately, using only a single approximate Green's function. In this paper, an error analysis of this method is presented. The error analysis shows an additional term, which represents the quasi-static image of the surface-wave poles plays a crucial role in the convergence and accuracy of this new method. As the extraction of poles is required, a recently proposed algorithm by Teo et al (IEEE Trans. Microwave Theory Tech., vol. 50, pp. 440-445, 2002) is also discussed and compared with existing methods in terms of computational speed.