Multi-directional cloaking structure design using topology optimization

Cloaking structure designs have been widely performed in a form of metamaterial development. However, physics-based design approach makes it difficult to define complex material profiles. This study proposes an alternative design method for multi-directional cloak design via topology optimization method using a dielectric material. The phase field design method, which uses the reaction-diffusion equations combined with the double well potentials as the update scheme for design variables, is employed for systematic derivation of a topological configuration of the cloaking structure. In addition, the concept of symmetric design sensitivity mapping is introduced for multi-directional cloaking effect. Design results of four-, six- and eight-directional cloak are presented, and experimental verification was performed for six-directional cloak using the fabricated structure through 3D printing technology.