Ultrasonic beam structures in fluid media

Weight, J.P.

doi:10.1121/1.391411

Cited by 36 publications

(19 citation statements)

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“…Notably, the CGL-free TRA(2 2 ,1 2 )/RRA(4 2 ,2 2 ) produced much smaller grating lobes than TRA(2 2 ,1 2 )/RRA(2 2 ,1 2 ) using the same number of active elements. The same result was also observed in the PW PSFs in Figure 8, which have much broader and lower grating lobes than the corresponding CW PSFs due to the well-known property of wide band beamforming [22]. Figure 9 shows the steered PW PSFs of the SRA pairs.…”

Section: Sparse Rectangular Arraysupporting

confidence: 72%

Sparse Rectangular and Spiral Array Designs for 3D Medical Ultrasound Imaging

Yoon

Song

2019

Sensors

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In three-dimensional (3D) medical ultrasound imaging with two-dimensional (2D) arrays, sparse 2D arrays have been studied to reduce the number of active channels. Among them, sparse 2D arrays with regular or uniform arrangements of elements have advantages of low side lobe energy and uniform field responses over the entire field of view. This paper presents two uniform sparse array models: sparse rectangular arrays (SRAs) on a rectangular grid and sparse spiral arrays (SSAs) on a sunflower grid. Both arrays can be easily implemented on the commercially available or the custom-made arrays. To suppress the overall grating lobe levels, the transmit (Tx) and receive (Rx) array pairs of both the array models are designed not to have grating lobes at the same locations in the Tx/Rx beam patterns, for which the theoretical design rules are also proposed. Computer simulation results indicate that the proposed array pairs for both the SRAs and the SSAs achieve peak grating lobe levels below –40 dB using about a quarter of the number of elements in the dense rectangular array while maintaining similar beam widths to that of the dense array pair.

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Section: Sparse Rectangular Arraysupporting

confidence: 72%

Sparse Rectangular and Spiral Array Designs for 3D Medical Ultrasound Imaging

Yoon

Song

2019

Sensors

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“…[1][2][3] The simplest method for simulation of ultrasonic fields is direct application of Huygens' principle. Experimental observations of the pulsed field of a circular ultrasonic transducer have shown that measured fields are in good agreement with theoretical results, calculated assuming an ideal piston behavior.…”

Section: Introductionmentioning

confidence: 99%

Simulation of ultrasonic fields radiated by a circular source through a layer with nonparallel boundaries

Jasiūnienė

Mažeika

Kažys

2006

The Journal of the Acoustical Society of America

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Active elements of ultrasonic transducers are separated from the medium by thick protective layers, which may have nonparallel front and back surfaces. The objective of this work was to develop a simple method suitable for fast calculation of ultrasonic fields radiated through a layer with parallel or nonparallel boundaries and enabling one to take into account multiple reflections inside the layer. The main presumption of the proposed method is the following: after refraction at the boundary between two media, the ultrasonic field consists of plane and edge waves as before refraction. The proposed simulation method is based on transformation of a multi-layered medium into a virtual one without internal boundaries and equivalent to the actual medium from the point of a view of the times of flight of the direct plane and edge waves. The method enables simulation of radiated ultrasonic fields even after multiple reflections within the layer with parallel or nonparallel boundaries. The examples of simulated and experimentally measured ultrasonic fields of the transducer with a nonparallel front surface of protection layer, radiating into the water, are presented.

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“…The first set has been used traditionally and leads to simple analytical expressions for the radiated fields [3]- [10]. In the second type of models, the impulse response of an ultrasonic transducer is approximated by the concept of a direct plane wave, that travels in the geometrical beam region straight ahead of the transducer, together with a diffracted edge wave that propagates as a toroidal wave from the edge of the transducer [11]- [15]. Other existing models belong to the nonparametric domain in which the vibration pattern of the transducer is calculated point by point over its surface, without giving a closed-form expression [16]- [18].…”

Section: Introductionmentioning

confidence: 99%

Experimental validation for the diffraction effect in the ultrasonic field of piston transducers and its influence on absorption and dispersion measurements

Temsamani

Vandenplas

Lumori

et al. 2001

IEEE Trans. Ultrason., Ferroelect., Freq. Contr.

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The aim of this work was to study the diffraction effects in the ultrasonic field of piston source transducers and their importance for accurate measurements of attenuation and dispersion in viscoelastic materials. In laboratory measurements, the diffraction phenomena are mainly due to the beam spread of the ultrasonic wave propagating in viscoelastic materials. This effect is essentially related to the estimated attenuation and dispersion in the material. In this work, a frequency domain system identification approach, using the maximum likelihood estimator (MLE), was applied to the measured data in order to determine a function for correcting the diffraction losses in both normal and oblique incidences for a large frequency band (300 kHz to 3 MHz). The effective radius of the used transmitter was determined by the inverse problem when ultrasonic beam propagation was investigated in a water medium. Using the estimated radius, the propagation through viscoelastic materials was established, and the acoustic parameters of these materials were estimated. Attention was paid to the determination of the attenuation and dispersion in the materials. These quantities were compared to those obtained without diffraction correction in order to see the influence of introducing the diffraction correction into the propagation model.

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Ultrasonic beam structures in fluid media

Cited by 36 publications

References 0 publications

Sparse Rectangular and Spiral Array Designs for 3D Medical Ultrasound Imaging

Sparse Rectangular and Spiral Array Designs for 3D Medical Ultrasound Imaging

Simulation of ultrasonic fields radiated by a circular source through a layer with nonparallel boundaries

Experimental validation for the diffraction effect in the ultrasonic field of piston transducers and its influence on absorption and dispersion measurements

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