1. Engineering Design and Computing LaboratoryDepartment of Mechanical and Process EngineeringETH Zurich 8092 Zurich Switzerland
2. Wave Propagation and Metamaterials LaboratoryDepartment of Mechanical Science and EngineeringUniversity of Illinois at Urbana‐Champaign Urbana IL 61801 USA
3. Division of Engineering and Applied ScienceCalifornia Institute of Technology Pasadena CA 91125 USA