Experimental demonstration of acoustic and electromagnetic metamaterials with conical dispersion

We experimentally demonstrate metamaterials with extreme dispersions by coiling up space with curled channels. An acoustic metamaterial is constructed with conical dispersion, supporting negative refraction with airborne sound. We have also demonstrated a double-negative microwave metamaterial by guiding through the cutoff-free TEM mode between two curled conducting wires. Field mappings and effective medium extraction confirm our studies.