Due to the practical importance and difficulties associated with their closed form solutions, the experimental and computational study of periodic planar multilayered structures, such as FSS in multilayered configuration and Multilayered Planar antennas array, are in complementary progress. During the past two decades, the widespread use of such methods has allowed a broad range of important scattering problems involving non-standard shapes, boundary conditions and material composition to be solved. In this sense, an efficient iterative technique based on the concept of wave is presented for computing periodic substrates in multilayered configuration. This paper presents an extensible approach of the iterative method to study multilayered substrates (n layers in which n = 2, 20) with spatial periodicity in multi- layer configuration. Our new approach is performed in order to study 3 dimensional structures by the method called Wave Concept Iterative Process (WCIP). This method is adapted in its original form to study 2 dimensional structures. The third dimension is modulated by transmission line as an approximation for every mode in spectral domain. The utility of the new WCIP appears because of its fast convergence and little consumption in memory.