Bandgap properties in metamaterial sandwich plate with periodically embedded plate-type resonators

•In this study, a novel plate-type resonator used in the metamaterial sandwich plate is proposed and the band structure and the transmission spectra of the metamaterial sandwich plate are investigated.•The formation mechanisms of the bandgaps are investigated via the analysis of the mode shapes of the plate-type resonator and face plate in a unit cell.•The effect of the geometric parameters on the bandgaps is investigated and the improvement of the plate-type resonator is also discussed.