Optimal origin selection for minimal multipolar modeling of bianisotropic metasurfaces

We develop a modeling framework based on multipolar decomposition that fully captures a metasurface electromagnetic response while using the minimum number of multipole moments, since excessive multipoles make modeling complex and computationally ineffective. One of the most important characteristics that determines the required number of multipole moments is the choice of the origin of the system of coordinates used for the multipolar decomposition. Here, we split multipolar contributions into even and odd parities and find their corresponding optimal scattering centers that minimize higher-order multipolar contributions. This allows us to model a metasurface, which would otherwise require higher-order multipoles, with only dipolar responses thus greatly simplifying its analysis.