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Proceedings Paper

Generation of Bessel limited-diffraction beams with hexagonal sparse arrays
Author(s): Nariman Majdi Nasab; Shahram Shirani; Mostafa Analoui
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Paper Abstract

The transducer driving function for Bessel beam has circular symmetry and can be generated by annular or 2-D arrays. In 2-D array, the elements are divided into a number of rings. Taking advantage of the circular symmetry, it was shown that arranging the elements in a hexagonal pattern instead of ordinary rectangular pattern could produce almost the same field pattern with 14% less elements. Our aim here is to eliminate some of the elements of the hexagonal array and obtain a hexagonal sparse array while maintaining the quality of the generated field. In our proposed method, starting from the outer most ring, a specific number of the elements of the ring are randomly selected and turned off. The field pattern of the resulting sparse arrays is simulated and compared to the field of the array with all of its elements active. If the relative mean square error is lower than a specific threshold value, more elements of the ring are turned off. This procedure is then repeated for the next ring until reaching the central ring. Our simulations for hexagonal sparse arrays show that for an error threshold of 4%, an acceptable Bessel beam can be generated only with 22% of the transducer elements used in the original hexagonal arrays. Generated beam still shows its non-diffracting property over a limited distance.

Paper Details

Date Published: 12 April 2000
PDF: 9 pages
Proc. SPIE 3982, Medical Imaging 2000: Ultrasonic Imaging and Signal Processing, (12 April 2000); doi: 10.1117/12.382230
Show Author Affiliations
Nariman Majdi Nasab, Univ. Nacional Autonoma de Mexico (United States)
Shahram Shirani, Univ. of British Columbia (Canada)
Mostafa Analoui, Indiana Univ. School of Dentistry (United States)


Published in SPIE Proceedings Vol. 3982:
Medical Imaging 2000: Ultrasonic Imaging and Signal Processing
K. Kirk Shung; Michael F. Insana, Editor(s)

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