  This work investigates acoustic wave transmission property through a zero
index metamaterials (ZIM) waveguide embedded with a general solid defect. Total
transmission and total reflection can be achieved by adjusting the parameters
of the solid defect. We comprehensively study how longitudinal/transverse wave
speeds of the solid defect affect the acoustic wave propagation through the
waveguide. A two-dimensional (2D) acoustic crystals (ACs) system with zero
index is used to realize these intriguing transmission properties. Thus, our
work provides more possibilities to manipulate acoustic wave propagation
through ZIM.
