Alternative and robust technique for the calculation of dispersion relations in grounded layered media

The study of the modal characteristics of grounded layered media is extremely important in the analysis of commonly employed microwave and optics circuits [1]. In a general case, this task requires the root searching of certain functions in the 2D complex plane, which provides the modal solutions of the structure under analysis. Different techniques have been proposed in the literature to solve this problem, ranging from using initial quasi-static asymptotic points for the complex search [2] to methods of integral nature [3], [4]. However, still a simple and efficient search strategy is not generally found.