Dispersion Analysis of Deep-Subwavelength-Decorated Metallic Surface Using Field-Network Joint Solution

Due to the abilities of remarkable field confinements and enhancements, plasmonic surfaces supporting spoof surface plasmon polaritons (SPPs) are important artificial structures with many potential applications. In this paper, we propose analytical derivation to the dispersion formulation of metallic surface with complicated subwavelength decorations using a field-network joint solution, which offers a new scheme to obtain the dispersion relations of plasmonic surfaces. Based on the proposed method, we could predict not only the dispersion relationship between the frequency and wavenumber but also the approximate near-field distribution on the plasmonic surface rapidly and accurately. As an example, we analyze a series of complex-decorated metallic plasmonic surfaces, with comparisons to the full-wave simulation and experiment. The analytical, numerical, and experimental results show that these plasmonic surfaces support electromagnetic surface modes that are similar to the SPPs at the optical frequency. Meanwhile, the calculated dispersion curve and field form have great matching to the simulation and measured results.