The propagation of Lamb waves in one-dimensional phononic crystal plates bordered with symmetric uniform layers

We investigated theoretically the band structures of Lamb waves in one-dimensional (1D) phononic crystal (PC) plates coated symmetrically with finite Tungsten or Silicon loading layers on both sides. Numerical results show that when a thin PC plate is bordered with the Silicon loading layers, both the midgap frequencies of the first band gaps of S0S0 and A0A0 modes change approximately linearly with the thickness of the Silicon loading layers. These two modes may be used as a sensor.