In efforts to use metamaterials to construct the world’s first working prototype of an invisibility cloak, researchers relied on multiphysics software.

Modeling software is generally used to show the fields and flows that are impossible to see with the eye or instruments. A group of researchers has done just the opposite: They ran computer simulations that showed it should be possible to fabricate the metamaterials necessary to build an “invisibility cloak” that makes an object invisible to certain frequencies.

The required electromagnetic properties of the cloaking shell are not of the sort found in natural materials. Knowledge of how to engineer materials with specific and complex electromagnetic properties has increased dramatically, and there is now an understanding of how to create “metamaterials” that behave as if they were continuous materials with permittivity, ε, and permeability, μ, that can vary with direction and position, and can even be negative. Early efforts at creating these materials were unsuccessful, but numerical simulations made it easy to study real-world material imperfections.

Figure 1: Computational domain and boundaryconditions for the Full-Wave Cloaking Simulation.The PEC (perfect electrical conductor)shell has a diameter of 0.2 m, which is 1.33 wavelengthsof the incident 2-GHz transverse electric(TE) polarized time-harmonic uniform planewave.