Complete location of poles for thick lossy grounded dielectric slab

In order to obtain accurate closed-form representations of the microstrip Green's functions, it is often necessary to find the locations of the proper and improper surface-wave poles. In this paper, we present an efficient and robust iterative algorithm based on contraction mapping, which can locate all the proper and improper solutions of the characteristic equations of the grounded dielectric slab. The dielectric may also be lossy.