Negative refraction of acoustic waves in a tow-dimensional square zigzag lattice structure

The negative refraction behavior and imaging effect for acoustic waves in a kind of two-dimensional square zigzag lattice structure are studied in this paper. Through the finite element method based on COMSOL we calculate the band structures and the equivalent frequency surfaces (EFS) of the considered system, thereby confirming the frequency range where the negative refraction presented. Due to the existence of a rotational symmetry in the calculated structure, a phase difference can be induced to the waves generated from a point source and a deviated negative refraction imaging can be achieved. This kind of phenomenon is also demonstrated by the simulation of two Gaussian beams incident to the structure from different direction with the same angle.