A modal beamformer for circular arrays of 1-dimensional particle velocity sensors

Particle velocity sensors are directional receivers that measure the particle motion associated with an acoustic wave rather than the scalar pressure that is obtained by omni-directional pressure sensors. Therefore, arrays of velocity sensors possess some desirable directional properties compared to conventional arrays of pressure sensors. In this paper, a modal beamformer for circular arrays of radially oriented 1-D acoustic velocity sensors is presented. It is shown that the highly directional modes of the acoustic field can be extracted from the sensor measurements using the spatial Fourier transform. These modes are weighted and combined to form narrow and steerable beams. The highest order of mode that can be extracted is limited by the number of vector sensors utilized in the array. Theoretical analysis and numerical simulations indicate that the proposed modal beamformer attains the same directivity performance as that of circular pressure sensor array beamformers but outperforms them in terms of w...