Demonstration of Scattering Suppression by a Near-Zero-Index Metamaterial Composed of Dielectric Spheres

We demonstrate microwave scattering suppression by a near-zero-index metamaterial (NZIM) composed of dielectric spheres. The NZIM is designed based on numerical simulations, and is shown by near-field measurements that the medium with dielectric spheres of yttria-stabilized zirconia with the dielectric constant 34 and the radius 1.5 mm arranged in a hexagonal lattice of the lattice constant 3.5 mm exhibits near-zero-index operations with a long wavelength of 22.51 GHz. It is also confirmed that the scattering by a defect of seven adjacent absent spheres is sufficiently suppressed by the NZIM.