Study on Bandgap Property of Three-Dimensional Star-Like Double-Arrow Lattice

Herein, a three-dimensional star-like double-arrow lattice is proposed, which is inspired by the double-arrow structure. Based on Bloch's theorem and finite element method, the calculation program is made up and the band structures are calculated. The calculation results demonstrate that the bandgap property of the double-arrow lattice is improved compared with that of a cross lattice. The parametric study is carried out and geometric parameters have strong effects on the bandgap property. As the angle between the external edge and symmetric line increases, the total bandgap width increases apparently, and the opening frequency of low-order bandgap decreases. This phenomenon reflects that the low-frequency bandgap property is improved. Via the isosurface of phase velocity and group velocity, the anisotropy is investigated. Strong anisotropy and energy focus appear, which can be used to design waveguides.