Application of meta-film surface impedance to equivalent transmission line model of meta-surface for scattering analysis

The basic design and analysis of scattering properties of meta-surfaces are usually performed by a transmission line model. The main idea is the decomposition of a periodic structure into a frequency selective surface(FSS) or a meta-film and dielectric slab as a spacing medium between the FSS and a ground plane. Hence, how precisely obtain the scattering property of the FSS is one of essential points. This paper modifies a surface impedance expression of the FSS composed of square patch array so as to enable us to apply for general case, and incorporates it into the equivalent transmission line model of the meta-surface. The effectiveness of the proposed model is numerically confirmed by comparing with the FDTD calculation.