Grate Lobes / Side Lobes Suppression for Sparse Array Design by Using Genetic Algorithms

Sparse arrays are popular in sonar, ultrasonic imaging and other acoustic equipment. For inter-element spacing larger than one wave length, there will be grate lobes for ordinary sparse array and may course ghost image for acoustic imaging and severe interference for underwater object detection. For some other applications of sparse array in which the reverberation suppression is crucial, the lower the side lobes of the array directivity pattern, the better the equipment performance, and then the low side lobe for the array directivity pattern is one of the main objects to be achieved for this kind of acoustic equipment. Using genetic algorithm to optimize the design of sparse array with randomly spaced elements to suppress the grate lobes/side lobes is introduced in this paper. Fitness function design and variable choosing method for genetic algorithms used in these kinds of application are presented.