Acoustic lens using sonic crystal for energy-transmission application

We design and characterize a two-dimensional sonic crystal (SC) to manipulate the propagation of acoustic waves by numerical simulation based on the finite-difference time-domain (FDTD) method and by ultrasonic measurement. Two types of SC for an acoustic lens effect are studied. One is a homogeneous periodic structure exhibiting negative refraction, and the other has a hetero-structure. Negative refraction behavior in the simulation is good agreement with the experiment in the frequency range around 1.2 MHz. We also observe a lens effect for far-field wave in the hetero-structured SC. These results indicate that a novel energy-transmission/harvesting device can be designed using SCs.