A full-wave numerical approach for modal analysis of 1-D periodic microstrip structures

In this paper, a full-wave numerical approach for the analysis and design of one-dimensional (I-D) printed periodic structures is presented. Electromagnetic-bandgap structures and leaky-wave antennas are important special cases of structures that can be analyzed. The proposed technique is based on a mixed-potential integral equation in a unit-cell environment solved by the method of moments in the spatial domain through a triangular Delaunay mesh. The I-D periodic vector and scalar Green's functions are derived in the spectral domain and an efficient sum of spectral integrals is carried out to obtain the spatial-domain quantities. An appropriate choice of the spectral integration path is used in order to consider leakage effects. The method developed here can thus analyze both bound and leaky modes on printed structures that have an arbitrary metallization within the unit cell.