Experimental demonstration of superdirectivity for coupled dimers of meta-atoms

A century-long quest for realizing superdirective antennas has got a new lease of life with the advent of metamaterials: Arrays of coupled meta-atoms capable of carrying slow short-wavelength magneto-inductive waves were shown to be promising candidates for realizing rapidly varying current distributions required for superdirectivity. This paper provides an overview of our work towards realizing a genuine superdirective meta-array, with only one element being driven. In particular, we report on our most recent experimental, numerical and analytical results, which, for the first time to our knowledge, confirm superdirective end-fire directivity reaching the maximum theoretical value. We formulate the conditions for superdirectivity in terms of shape and size of the meta-atoms and discuss implications of our results for future work on superdirective metamaterials.