Search "superdirective superconducting antenna". With normal conductors the directivity of an antenna depends on how many wavelengths it spans; the summation of the currents over the effective aperture. With superconducting materials you can exploit the weirdness in current distribution to make very directional antennas that are
small relative to the wavelength.
It could be a game changer for making efficient directional small receive antennas. Normally electrically small antennas are just super inefficient but it's made up for either on the transmit side (like with high power AM radio) or with most of the gain coming from some low noise amplifier (like small UHF wireless devices).