Volumetric metamaterials versus impedance surfaces in scattering applications

Demonstration and Control of "Spoof-Plasmon" Scattering from 3D Spherical Metaparticles

Geometries that replicate the behavior of metal nanostructures at much lower frequencies via texturing surfaces so they will support a surface wave have been a central pillar of metamaterials research. However, previous work has focused largely on geometries that can be reduced to symmetries in one or two dimensions, such as strips, flat planes, and cylinders. Shapes with isotropic responses in three dimensions are important for applications, such as radar scattering and the replication of certain nanoscale behaviors. This work presents a detailed exploration of the scattering behavior of 3D spherical "spoof plasmonic" metaparticles, based on the platonic solids. Their behavior is compared to an effective medium model through simulation and experiment, and the vast range of behaviors that can be produced from a metal sphere of a given radius via tuning its internal structure is explored in detail.

Simple low-cost 3D metal printing via plastic skeleton burning

Additive manufacturing of complex volumetric structures opened new frontiers in many technological fields, turning previously inconceivable designs into a practical reality. Electromagnetic components, including antenna and waveguiding elements, can benefit from exploring the third dimension. While fused deposition modeling (FDM) polymer printers become widely accessible, they manufacture structures with moderately low electromagnetic permittivities, compared to metals. However, metal 3D printers, being capable of producing complex volumetric constructions, remain extremely expensive and hard to maintain apparatus, suitable for high-end market applications. Here we develop a new metal printing technique, based on a low-cost and simple FDM device and subsequent electrochemical deposition. For testing the new method, we fabricated several antenna devices and compared their performances to standard printed FeCl₃ etched board-based counterparts, demonstrating clear advantages of the new technique. Our new metal printing can be applied to manufacture electromagnetic devices as well as metallic structures for other applications.