Properties of the beampattern of weight- and layout-optimized sparse arrays

Holm, Sverre; Elgetun, Bjørnar; Dahl, Geir

doi:10.1109/58.655623

Cited by 127 publications

(77 citation statements)

References 16 publications

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“…This work focuses on the synthesis of reconfigurable multiple patterns with fewer elements by selecting the common ones with optimized excitation amplitudes and phases. Some synthesis methods by using nonuniform element positions [16][17][18][19][20][21][22], or by applying thinning techniques [23][24][25], have been presented to effectively reduce the number of elements. However, these reviewed techniques are proposed for the synthesis of single-pattern arrays.…”

Section: Introductionmentioning

confidence: 99%

“…In addition, the choice of a symmetrical layout and symmetrical amplitudes can greatly simplify the beamforming network. Hence, this choice has been widely adopted by many single-pattern synthesis methods, for example, in [23] and [31]. To cast the problem of finding the common element positions for multiple patterns into the form of linear programming, we introduce an auxiliary variable to define the common upper bound of the real and imaginary parts of multiple excitations for each element.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Synthesis of Sparse or Thinned Linear and Planar Arrays Generating Reconfigurable Multiple Real Patterns by Iterative Linear Programming

You¹,

Zhu

Tan³

et al. 2016

PIER

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Abstract-It is shown in this paper that the problem of reducing the number of elements for multiplepattern arrays can be solved by a sequence of reweighted 1 optimizations under multiple linear constraints. To do so, conjugate symmetric excitations are assumed so that the upper and lower bounds for each pattern can be formulated as linear inequality constraints. In addition, we introduce an auxiliary variable for each element to define the common upper bound of both the real and imaginary parts of multiple excitations for different patterns, so that only linear inequality constraints are required. The objective function minimizes the reweighted 1 -norm of these auxiliary variables for all elements. Thus, the proposed method can be efficiently implemented by the iterative linear programming. For multiple desired patterns, the proposed method can select the common elements with multiple set of optimized amplitudes and phases, consequently reducing the number of elements. The radiation characteristics for each pattern, such as the mainlobe shape, response ripple, sidelobe level and nulling region, can be accurately controlled. Several synthesis examples for linear array, rectangular/triangular-grid and randomly spaced planar arrays are presented to validate the effectiveness of the proposed method in the reduction of the number of elements.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Synthesis of Sparse or Thinned Linear and Planar Arrays Generating Reconfigurable Multiple Real Patterns by Iterative Linear Programming

You¹,

Zhu

Tan³

et al. 2016

PIER

View full text Add to dashboard Cite

show abstract

“…However, the results indicate that the grating lobe levels are at least 6 dB below the intensity at the focus; serious damage on normal tissue is not expected. In addition, a sparse array (64 active elements) can benefit from the reduced number of elements compared with a full matrix array (195 elements) [14,29].…”

Section: Computational Simulationsmentioning

confidence: 99%

Design of Focused Ultrasound Array for Non-Invasive Transesophageal Cardiac Ablation~!2009-08-30~!2009-11-26~!2010-02-12~!

Lee¹,

Francischelli²,

Smith³

2010

TOMDJ

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Atrial fibrillation (AF) is the most common type of arrhythmia, affecting more than 2.2 million Americans. One effective treatment is cardiac ablation, which shows a high rate of success in treating paroxysmal AF. As a prevailing modality for this treatment, catheter ablation using radiofrequency has been effective, but comes with measurable morbidity and significant costs and time associated with this procedure for permanent or persistent AF. To address these issues, an ultrasound applicator for cardiac ablation without surgical incisions or blood contact was designed, developed and evaluated in this study. To initially design a transesophageal applicator using therapeutic ultrasound capable of creating atrial lesions from the esophagus, sound pressure fields in a simple tissue model were numerically determined. Based on the simulation results for transducer arrays together with current transesophageal medical devices and the throat anatomy, we designed, fabricated, and tested a focused ultrasound applicator that can be inserted into the esophagus for noninvasive cardiac ablation. The ultimate goal in this project is to bring this applicator as close as possible to the heart to effectively deliver ultrasound energy and create electrically isolating lesions in myocardial tissue, which replicate the currently used Maze procedure. The transducer design is a two-dimensional sparse phased array with flat tapered elements operating at 1.6 MHz. This array uses 64 active elements spatially sampled from 195 rectangular elements. Its probe head housing is 19 mm in diameter and incorporates an acoustic window. A prototype applicator has been successfully tested in vitro using fresh porcine myocardial tissue. The results demonstrated a potential applicability of an ultrasound applicator to transesophageal cardiac surgery in AF treatment.

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“…However, it is not easy to implement a large-scale element array because of its high cost, which has been a major factor inhibiting its wider application within the field of medical ultrasound imaging [9]. To resolve this problem, sparse array technology has been studied [10][11][12]. By randomly eliminating some elements, sparse arrays can reduce the number of elements while maintaining sharply focused beams.…”

Section: Introductionmentioning

confidence: 99%

An experimental study of ultrasonic imaging with a reduced number of array elements using the envelope method

Sakamoto

Taki

Sato

2011

Acoust. Sci. & Tech.

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In this experimental study, we conducted measurements using a 128-element ultrasonic array system. Ultrasonic images generated by the conventional migration method were compared with the Envelope method, a promising high-resolution imaging technique. To determine the image quality of an ultrasonic measurement system that uses fewer elements, we selected 64, 32, 16 and 8 elements from the total 128 elements used in our imaging process. The results show that in homogeneous environments the Envelope method can produce clearer images than those produced by the conventional method even when using a small number of elements, suggesting that the introduction of the Envelope method could be an effective way of reducing the number of elements employed in array systems, while maintaining high image quality.

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Properties of the beampattern of weight- and layout-optimized sparse arrays

Cited by 127 publications

References 16 publications

Synthesis of Sparse or Thinned Linear and Planar Arrays Generating Reconfigurable Multiple Real Patterns by Iterative Linear Programming

Synthesis of Sparse or Thinned Linear and Planar Arrays Generating Reconfigurable Multiple Real Patterns by Iterative Linear Programming

Design of Focused Ultrasound Array for Non-Invasive Transesophageal Cardiac Ablation~!2009-08-30~!2009-11-26~!2010-02-12~!

An experimental study of ultrasonic imaging with a reduced number of array elements using the envelope method

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