Metamaterial Insulator Enabled Superdirective Array

Metamaterial EM insulators are shown to suppress mutual coupling between densely packed array elements. This technique allows for array element design in isolation, without consideration of adjacent elements and mutual coupling effects. Suppressing mutual coupling allows for denser packing and enhanced directivity in antenna arrays approaching the superdirective theoretical maximums. Metamaterial isolation walls 0.05lambda0thick exhibit 20 dB peak isolations with 10 dB isolation bandwidths of 2-6% and very low losses. These insulators achieve lower than -30 dB coupling levels for 0.2lambda0periodicity arrays. A simulated 1.18lambda0five element broadside array exhibits a superdirective 65 degree first-null beamwidth with -9.5 dB side-lobes and when physically fabricated, experiment validates theory with a squinted 75 degree first-null beamwidth and only slight degradation of sidelobe levels. The main beam of the metamaterial insulated array is steerable over a full +/-90 degree horizon with little scan loss and no instances of scan blindness, a null can be placed to any angle including broadside, and as narrow as 25 degree peak-to-null separation is possible