Figure 1

(a) Dispersion relations of SMPs (the dashed lines) and regular mode (the solid line) for \({{\rm{H}}}_{0}=1785\,{\rm{G}}\) in the YIG-air-metal structure. The middle shaded area indicates the one-way region for the waveguide, and the other shaded areas indicate the zones of bulk modes in the YIG. (b) Simulated electric field amplitudes at \(f=9\,{\rm{GHz}}\). (c) Schematic of the YIG-air-metal structure under an external magnetic field H₀. The thickness of the air layer is \(d=1\,{\rm{mm}}\).