High-Order Modes Analysis of Complex Plasmonic Surface Using the Field-Network Joint Solution

The plasmonic surface is made of metallic surface with deep sub-wavelength decorations, which are designed to mimic the surface plasmon polaritons at lower frequency. Recently, high-order modes in some special structures are analyzed. In order to analyze the dispersion problem of high-order modes of complex lossless structures faster and simpler, a convenient and simple method using the average input wave impedance obtained by a field-network joint solution is proposed. Meanwhile, based on Forster's reactance theorem, high-order modes of the complex structure always exist. Then, the dispersion curves of the high-order modes calculated using proposed method are in perfect match with the simulated results, which can verify the effectiveness and correctness of the proposed method. Additionally, the simulated and experimentally measured electric field distribution of high-order modes have great agreement. Using the proposed method, one can quickly obtain dispersion curve of a plasmonic structure to verify or estimate structure design. Hence, the proposed method may make a big step forward for obtaining the special dispersion relations.