Analytic theory of an edge mode between impedance surfaces

Abstract

An eigenmode analysis is presented of the electromagnetic field which occurs between two complementary surface impedances. The analysis is based on the generalized reflection method which is a generalization of the Sommerfeld-Maliuzhinets technique. Numerical results are presented and validated against independent Comsol simulations. Also, the characteristic impedance and phase velocity are defined and calculated for further investigation of the structure.

Electromagnetic‐Dual Metasurfaces for Topological States along a 1D Interface

“…Furthermore, the electric and magnetic field distributions over the cross section of the interface waveguide, which are plotted in Figure d, show that the edge mode is concentrated along the line intersection of the thin metasurface films and decays rapidly into the surrounding bulk/surfaces. Uniquely, this characterizes the edge states as 1D line waves in contrast to the typical 2D surface edge states in previously reported PTIs.…”

“…Importantly, unlike the majority of existing PTIs, including those with finite thickness, the topological phases here arise due to engineering surface waves rather than bulk waves. Consequently, the ensued topological edge modes, which occur at the boundary of such system, are confined along a 1D line rather than a 2D surface interface, despite the lack of enclosing structures. In addition, we present a proof‐of‐concept in the microwave regime and experimentally show backscattering‐immune propagation of the gapless edge modes around sharp corners by direct imaging of the near field.…”

Adiabatic Mode-Matching Techniques for Coupling Between Conventional Microwave Transmission Lines and One-Dimensional Impedance-Interface Waveguides

“…An electromagnetic mode can be supported by an impedance surface with an exponential decay away from the surface and a propagation function . The surface impedances for TE and TM polarized waves are [18,24,37]…”

“…Topological insulators support waves at the interface of trivial and non-trivial materials in topological space [20,21]. In the past several years, researchers have found a different one-dimensional (1D) impedance-interface mode, called a line wave (LW) mode, at the interface of two planes with different surface impedances from microwave to optical bands [22][23][24]. Further researches focusing on similar waveguides were reported recently [25,26].…”

Classical-to-topological transmission line couplers

“…EM duality 12 and 2. the pseudospin degree of freedom for photons. As analyzed in 13 - 15 , when a 2D material characterized by a capacitive surface impedance Z c is placed next to another of complementary inductive surface impedance Z i , there can exist an EM mode at the interface. By necessity, such a mode is tightly confined to the interface and can therefore be considered a 1D mode, or line wave.…”