A review of parametric acoustic array in air

In this review paper, we examine some of the recent advances in the parametric acoustic array (PAA) since it was first applied in air in 1983 by Yoneyama. These advances include numerical modelling for nonlinear acoustics, theoretical analysis and experimentation, signal processing techniques, implementation issues, applications of the parametric acoustic array, and some safety concerns in using the PAA in air. We also give a glimpse on some of the new work on the PAA and its new applications. This review paper gives a tutorial overview on some of the foundation work in the PAA, and serves as a prelude to the recent works that are reported by different research groups in this special issue.