A four-element array design for the implementation of the third-order super-cardioid beam pattern

This paper presents a practical acoustic source that can implement the third-order super-cardioid beam pattern (SCBP). Based on the product theorem of the array, the third-order dipole beam pattern can be implemented based on the first-order and second-order dipole beam patterns so that a four-element array is designed. In addition, the second-order dipole beam pattern can also be implemented by the same four-element array. Hence, a four-element array is designed to implement the third-order SCBP. Subsequently, the single-sided radiation flextensional transducer—which is a type of low-frequency underwater acoustic transducer—is selected as the array element of the four-element array that is studied and analyzed by means of the finite element method. Finally, a four-element array prototype is fabricated and tested leading to the conclusion that the special four-element array combined with the product theorem provides a practical way for the implementation of the third-order SCBP.