Reduction of Near-Field Grating Lobes in Sparse Acoustic Phased Arrays

<p>Acoustic phased arrays with inter-element spacings of greater than one half-wavelength will produce grating lobes that decrease the usefulness of the array. With many array configurations, the near-field and far-field character of these lobes is significantly different -- an optimization of the array configuration to reduce grating lobes in the far-field can have little bearing on the performance of the array in the near-field.</p> <p>The focus of this thesis is the reduction of grating lobes in the near-field by iterative optimization. Genetic algorithms are employed to choose inter-element spacings which are able to reduce the magnitude of grating lobes at select distances in the near-field. The genetic algorithm produced configurations that are theoretically able to suppress grating lobes in the near-field.</p> <p>In order to verify the efficacy of these configurations, a hardware test platform was constructed. The platform permits largely automated evaluation of the near-field character of arbitrary array configurations. Using the test platform, several of the arrangements were constructed and evaluated. The results of these evaluations confirm that it is possible to reduce the grating lobes of sparse phased arrays in the near-field.</p>

Name thesis:degree_name

Master of Science in Electrical & Computer Engineering

Level thesis:degree_level

Thesis - Open Access

Discipline thesis:degree_discipline

Electrical, Computer, Software, and Systems Engineering

Year

2013

Author dc:creator

• Rudolph, Dylan

• acoustic arrays
• grating
• lobes
• Electrical and Computer Engineering

Repository record dc:identifier

https://commons.erau.edu/edt/125

OAI identifier oai:identifier

oai:commons.erau.edu:edt-1124