Nonreciprocal Concentric Metasurface Cloak

We introduce here a nonreciprocal (NR) cloak, based on multiple circular concentric metasurfaces, where the curved metasurfaces bend the electromagnetic energy around a cloaked region similar to a conventional reciprocal cloak. On the other hand, we replace one of the reciprocal metasurfaces by a proper nonreciprocal one such that a source placed inside the cloaked region can effectively send signals to the outside. The simulation results confirm the perfect cloak performance and capability of the NR cloak as a transmitter.