A grating lobes suppression method for a steerable parametric array loudspeaker

A parametric array loudspeaker (PAL) is a highly directional sound source with small aperture size. To achieve accurate sound projection, the steerable PAL is implemented by the use of the phased array technology. In this paper, the sound field model based on the Westervelt equation of a practical steerable PAL is presented, and a quasi-linear approximation is adopted to obtain the spatial sound pressure distribution. By applying the phased array technology, the audio beam can steer to the target direction. However, the grating lobe arises when the transducers are spaced more than half a wavelength, which disturbs the effect of beam steering. We further propose the grating lobes suppression method and apply it to the steerable PAL. Simulation results validate the performance of the proposed method.