An efficient robust optimization methodology for metamaterial unit design

A metamaterial (MM) generally works on a resonance mode, and its permeability will vary sharply around this resonance frequency. Consequently, the performance of a MM will be largely degraded if it is designed using a traditional optimization technique without considering these inevitable imperfections in fabrications. In this regard, the robustness of a solution must be included in the design optimization of a MM, exacerbating additional computational burdens to the already costly design procedure arising from the application of a high-fidelity model. Consequently, it is demanding to reduce the function calls for a high-fidelity model in the robust design of a MM. In this point of view, an optimization methodology by combining the genetic algorithm (GA) and a local search surrogate model is proposed for efficiently robust optimizations of a MM unit.