Superdirective “meta-molecules”

We show that superdirectivity can be achieved in metamaterial structures by relying on magneto- and electro-inductive waves capable of providing the rapidly varying current distribution needed. Following our previous studies on dimers we extend in this paper our analysis to trimers of split rings coupled both magnetically and electrically. We deduce rigorous analytical conditions for achieving superdirectivity in terms of separation and detuning of meta-atoms, quality factors and mutual coupling. Our results may pave the way to the first realization of genuine superdirective metamaterials.