A Study On Acoustic Metasurface For Sound Wave Manipulation

Metasurface is a new concept in recent years.Because of its subwavelength thickness,it has attracted wide attention and became a hot research topic.The acoustic metasurface proposed by analogy optical metasurface has also become an important research subject in the field of acoustic metamaterials.In this paper,firstly,a variety of ways to control acoustic wave using impedance matched metasurface are studied,and the effects of phase arrangement of acoustic metasurface on wave manipulation are explained,and several applications of metasurface are simulated,such as anomalous reflection and refraction,negative reflection,negative refraction,and acoustic incident plane wave converted into acoustic surface wave.Then,a new type of transmitted acoustic metasurface based on Helmholtz resonators is designed,and the performance of the sound wave control is verified by simulation.Several potential applications and characteristics are demonstrated,such as an acoustic transmitted isolator,an ultrasonic Bessel beam generator,frequency broadening effect of anomalous refraction and focusing and so on.In addition,according to the relationship between the topological charge number of the vortex wave and the phase distribution in a loop,the topological charge number of acoustic vortex beam is controlled by the impedance matched acoustic metasurface with the arrangement of the phase distribution.Finally,the phase defect is introduced into the acoustic vortex beam,and the defect wave is obtained,which is expected to play a role in particle control.The above simulated results have some reference value for device design based on acoustic metasurface.The one main feature of the acoustic metasurface is subwavelength thickness.The acoustic devices based on this are easy to develop in the direction of miniaturization and integration.The other important feature of acoustic devices is the arrangement of carefully designed phase distribution to realize the arbitrary manipulation of acoustic waves.The advantage of miniaturization and the ability to control acoustic waves in arbitrarily ways are the core values of metasurface.