Four-element planar arrays focus a point-like source based on the artificial iterative phase conjugated processing

The artificial iterative phase conjugated processing is an improved algorithm of phase conjugation and has been proven to focus a sharp focal spot using linear array. Because cross-shaped four-element planar array and triangular four-element planar array are widely used in the situation of little acoustic measuring points , their focal patterns by the artificial iterative phase conjugated processing are discussed in this paper. Theory analysis and numerical simulations gives conclusions. Based on the artificial iterative phase conjugated processing, two arrays focus a smaller focal spot than that by phase conjugation. As their iterate number increases, focal spot size decreases but the sidelobe amplitude becomes big. Considering the focal spot size and sidelobe interference, the triangular four-element array has a clearer pattern than the cross-shaped one .