Efficient emission of directional sound waves by using subwavelength meta-cavities Zhang, Likun ; Fan, Xudong ; Zhao, Jiajun ; Liang, Bin ; Cheng, Jianchun ; Wu, Ying ; Landi, Maryam Abstract Publication: Acoustical Society of America Journal Pub Date: September 2018 DOI: 10.1121/1.5067802 Bibcode: 2018ASAJ..144R1763Z