Non-reciprocity and control of Doppler effect in antenna systems induced by active time-varying metamaterials and metasurfaces

In this contribution we present the recent advancements of active time-varying modulated metamaterials and metasurfaces in the antenna field. At first, we present the physical insights of the unusual interaction arising between the electromagnetic field and such kind of active metamaterials, metamaterial-inclusions and metasurfaces. Then, we discuss about the magnet-less non-reciprocity and artificial red-/blue-shift of the interacting signal, which enable the conceiving of non-reciprocal antennas and Doppler cloaks, respectively. A filtering nonreciprocal horn antenna and metamaterial/metasurface-based cloaking devices hiding the velocity of a moving object are presented.