Analysis of periodic structures using finite-difference time-domain method

Periodic structures are of great importance in electromagnetics these days due to their wide range of applications such as frequency selective surfaces (FSS), electromagnetic band gap, periodic absorbers, metamaterials and many others. The aim of this work is to develop several algorithms to analyze different types of electromagnetic periodic structures using the constant horizontal wavenumber finite-difference time-domain periodic boundary condition (FDTD/PBC). A new FDTD/PBC approach is introduced to analyze the scattering properties of general skegrid periodic structures. The approach is simple to implement and efficient in terms of both computational time and memory usage. In addition, an efficient hybrid FDTD generalized scattering matrix (GSM) technique is developed to analyze multilayer periodic structure. The technique is based on the FDTD constant horizontal wavenumber approach to compute the scattering parameters of each layer. The new technique saves computational time and storage memory. Moreover, a new algorithm is developed to analyze dispersive periodic structures, the algorithm is easy to implement and efficient in both computational time and memory usage. All the developed algorithms are validated through several numerical test cases