3D microscale metamaterial structures and methods of making. The metamaterial structure includes a polygonal structure having a plurality of panels connected to one another at structure corners. A metal resonator pattern is provided on each of the panels. The resonator patterns of neighboring panels are electromagnetically coupled to one another across a gap between the resonator patterns at the corresponding structure corner. The panels can be a polymer material, layers of graphene oxide, etc. The metamaterial structure can be a 3D octagram split-ring resonator, and is completely isotropic. The 3D metamaterial structure can be made by a self-folding process.
