A low-frequency superdirective acoustic vector sensor array

This paper provides a novel acoustic vector sensor array architecture for superdirectivity at low frequencies. It has a uniform 3 by 3 rectangular geometry of intersensor spacing less than 0.04 wavelength over its operation frequency band, with an up to 10.4 dB of directivity index in cylindrically isotropic noise. This is realized through a mode domain approach, which accesses the acoustic modes by fitting certain multipole models to the wavefield observations. Field experiments show that this is a practical solution of implementing a miniaturized vector sensor array with superdirectivity.