“…For the SM, a 1D periodic model is a general choice for exploring mechanism of the BGs. 20,26,32 However, in practical applications, the design of the 2D periodic SM is more important and necessary. 18,37,41 In addition, due to some uncontrollable factors in actual situations, such as the difficulty of achieving perfect continuity between different materials, large-scale field experiments are still needed to verify the SMs with ultra-wide and low-frequency bandgaps for surface waves.…”