Beamforming with an array of sensors is an advanced signal processing technique for directional signal transmission or reception. This directionality is achieved by phase shifts of received signals of each sensor for the constructive interference of wavefronts, resulting in the amplification of the signal from a particular direction. In this study, the use of an asymmetric sensor array is proposed to reduce the effects of ‘spatial aliasing’, which is typically encountered in the structural health monitoring (SHM) practice when employing beamforming. In this technique, a sensor array is asymmetrically and closely deployed for robust beamforming based source localization. This sensor deployment has a great effect on suppressing the phenomenon that wave signals are constructively shifted even on other directions. The proposed asymmetric sensor array is to reduce the spatial aliasing error without using any advanced signal processing techniques. In order to demonstrate the proposed sensor array technique, several simulation and experimental investigations are carried out with various symmetric and asymmetric sensor arrays. For the experiments, a complicated composite structure including honeycomb core, spars, and holes is used. The performance comparison is then made to demonstrate the performance of the proposed sensor array technique. The superior robustness of the asymmetric sensor array is confirmed by both simulation and experiment results in complicated structures.
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