Local full-wave methods for accurate modelling of large area meta-surfaces

Designing large-area meta-surfaces is a daunting numerical task. The sub-wavelength size of the individual meta-atoms requires a full-wave solver for Maxwell's equations. Practical meta-surfaces need to have an active area on the order of 1 mm² or above. These sizes are orders of magnitude larger than what is feasible using known full-wave algorithms both in available memory and time requirements. Traditionally, approximations are made to design meta-surfaces of mm² size and above. Recently large area meta-surface fabrication has been shown. With this capability, the demand for large area meta-surface design (>1000 λ) continues to increase. In this paper we present overlapping domain analysis (ODA) as a novel approach to model large area meta-surfaces with higher accuracy than the local periodic approximation (LPA) but capable of larger areas than rigorous full-wave calculations. We compare the effect of the approximation chosen on the simulated performance of the lens for various numerical apertures.