Localized Spoof Surface Plasmon Skyrmions Excited by Guided Waves

Recently, skyrmions are constructed in the system of localized spoof surface plasmons (LSSPs), showing topological robustness and near-equidistant multi-resonant response. Guided wave excitation of the LSSP skyrmions plays an elementary role in large-scale planar integration and construction of complex networks. However, it is not investigated. In this study, the LSSP skyrmions are excited by guided waves supported by two kinds of widely used transmission lines, microstrip line and coplanar waveguide. Space-coiling meta-structures with different shapes that support LSSP skyrmions are etched on the ground planes as defected ground structures (DGSs). All structures including resonator, transmission line, input and output ports are in one plane. The structures are fabricated on printed circuit boards (PCBs) and the near-equidistant multi-resonant spectra of the LSSP skyrmions are measured. Moreover, to reduce the material loss, the structure is made on MgB₂ superconducting film, and the quality factor (Q-factor) is increased by seven times compared to the corresponding mode on PCB. This study paves the way for the massive planar integration of the LSSP skyrmions and the construction of complex networks with the LSSP skyrmions, and provides an idea for developing metasurfaces with low material loss in the microwave and terahertz bands.