A novel beamforming technique that resembles the principle of interference is proposed for sonar arrays to suppress the side lobes while the main lobe is kept intact. It uses two window functions. The first one is a rectangular function that produces a primary beam pattern. A secondary new window function is derived and its beam pattern is steered such that the null or trough of the main lobe of the new window coincides with the peak or crest of the first side lobe of the rectangular window and so on to other major side lobes. Pattern multiplication was used to get a final beam pattern. The approach is simulated and verified through a sonar array with 24 hydrophone sensors.
A Side-Lobe Suppression Method Based on Coherence Factor for Terahertz Array Imaging
