A Generic Approach for Computation of Near-Field and Far-Field Pattern of Beamforming Acoustic Transducer Array

Abstract

This paper addresses a mathematical formulation to determine the radiation performance of an acoustic beamforming array, which is valid for both near-field and far-field regions. The developed beamforming analysis is generic for application to any array configuration, with the array elements having a radiating aperture of canonical contours. The beamforming analysis presented in this paper for the acoustic transducer array is obtained by the process of vector summation of radiated fields from the elements of the acoustic transducer array with an array factor and beam steering phase factor. The initial validity of the beamforming analysis is examined by considering the far-field region as a particular case of the near-field region with the relevant distance criterion. The numerous simulation studies presented in this paper show that the proposed method produces excellent results with the distinct structure of sidelobes at a distance RNF ≥ 0.5D2/λ from the acoustic aperture of (7(1) linear and (7(7) planar array of acoustic transducers. If the distance between the transducer array and the point of observation is very low (RNF < 0.5D2/λ), simulation results indicate a less directive main beam. The two-dimensional near field beam steering method proposed in this paper finds the significant utility in many practical applications such as Underwater Acoustic Imaging (UAI) systems and Underwater Acoustic Communication (UAC).