Optimal design of electromagnetic cloaks with multiple dielectric materials by topology optimization

Abstract

This paper presents an optimal design method for electromagnetic cloaks composed of multiple dielectric materials based on a topology optimization. To obtain optimal configurations that are perfectly free from intermediate materials, so-called grayscales, we apply a Multi-Material Level Set topology description model. The level set functions that are design variables are updated using topological derivatives that also function as design sensitivities, and we derive the topological derivatives for multiple materials. Three numerical examples demonstrate the validity of the proposed method and the advantage of using multiple materials.