Interface Waves in Parallel-plate Metasurface Waveguides with Duality Symmetry

We propose a parallel-plate metasurface waveguide, where duality symmetry is realized by spatially arranging two kinds of metasurfaces with opposite equivalent reactance, inductive and capacitive. Period patch and grid arrays are designed to achieve different artificial impedance surfaces. Equivalent impedance boundary conditions are extracted based on simulated dispersion curves of unit cells. Simplified uniform waveguide models based on impedance boundaries are established to further investigate robust transport of interface waves along various routes. Due to the protection from duality symmetry, the interface waves are tightly bounded at the center of the waveguide. The proposed waveguide may pave an important research direction in wireless components design.