Generation of Bessel limited-diffraction beams with hexagonal sparse arrays

Nariman Majdi Nasab; Shahram Shirani; Mostafa Analoui

doi:10.1117/12.382230

12 April 2000 Generation of Bessel limited-diffraction beams with hexagonal sparse arrays

Nariman Majdi Nasab, Shahram Shirani, Mostafa Analoui

Proceedings Volume 3982, Medical Imaging 2000: Ultrasonic Imaging and Signal Processing; (2000) https://doi.org/10.1117/12.382230
Event: Medical Imaging 2000, 2000, San Diego, CA, United States

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.

Citation Download Citation

Nariman Majdi Nasab, Shahram Shirani, and Mostafa Analoui "Generation of Bessel limited-diffraction beams with hexagonal sparse arrays", Proc. SPIE 3982, Medical Imaging 2000: Ultrasonic Imaging and Signal Processing, (12 April 2000); https://doi.org/10.1117/12.382230

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