A linear sensor array with self-bending sensitivity

Abstract

Self-bending wave fields exhibit an envelope that seemingly bends in space under free-field conditions. They are created by wave fronts that fold along a caustic. In this paper, we invert the concept by exploiting the reciprocity principle of the Helmholtz equation in order to create a linear sensor array whose sensitivity seemingly bends in free space in the nearfield of the array. The sensor array therefore allows for listening around a distracting source, a jammer, or a physical object as sensitivity nulls can be placed at a defined distance. We illustrate the operating range and the robustness of the solution based on numerical simulations. For the presented scenario, an attenuation of more than 50 dB in a controllable region in space is achieved in a frequency range of more than two octaves.Index Terms-sensor array, self-bending acoustic beams, nearfield beamforming, null steering