Focusing Ultrasonic Wave using Metamaterial-based Device with Cross Shape

Focusing on the ultrasonic wave became a point of interest for many researchers in recent years. In this paper, we present the design of the acoustic metamaterials device with the broadband gradient index in the water medium, whose effective index of refraction can be controlled. The device consist of an organized array of cross shape unit cells, the focusing effect is obtained by controlling in the geometry parameters of cross shape and the arrangement between each unit cell in the device. The finite element numerical simulations were performed in the frequency domain to study the focusing effect of the structures at designed frequencies on the propagation of the ultrasonic wave and experiments also conducted using the same design with the simulations. The experiment results are in the good agreement with the simulation results which shows the applicability of this device for focusing ultrasonic wave.