An Experimental Investigation of the Cross-Coupling between Elements of an Acoustic Imaging Array Transducer

1982 ◽  
Vol 4 (1) ◽  
pp. 44-55 ◽  
Author(s):  
J. Fleming Dias
Keyword(s):  
Experimental Investigation ◽  
Surface Waves ◽  
Common Ground ◽  
Cross Coupling ◽  
Acoustic Mode ◽  
Acoustic Imaging ◽  
Range Resolution ◽  
Array Transducer ◽  
Coupling Mode ◽  
The Cross

In a phased array acoustic imaging transducer, the cross coupling between elements of the array can lead to a loss in range resolution, cause an increase in rolloff with angle of the sector scan, and increase the ringdown time. In this paper, we present results of an experimental investigation of an acoustic mode that couples the elements through the propagation of surface waves on the surface of the acoustic absorber. These results indicate that the strength of the mode is enhanced by the coherent reflections from adjacent neighbor elements which act as efficient reflectors of the surface waves. We also demonstrate a technique whereby reflections can be made to interact destructively to reduce the strength of that coupling mode. A further reduction can be obtained by stiffening the structure by bonding to the tops of the elements a thick brass foil and by using it as a common ground connection.

Construction and Performance of an Experimental Phased Array Acoustic Imaging Transducer

1981 ◽  
Vol 3 (4) ◽  
pp. 352-368 ◽  
Author(s):  
J. Fleming Dias
Keyword(s):  
Silicone Rubber ◽  
Common Ground ◽  
Phased Array ◽  
Acoustic Imaging ◽  
Metal Foil ◽  
Acoustic Lens ◽  
Array Transducer ◽  
The Common ◽  
And Performance ◽  
Pulse Echo

A technique for electrically connecting to the PZT elements in a phased array transducer of a cardiac imaging probe is described. The transducer is a stack consisting of a PZT substrate with metallized faces and is bonded to an acoustic absorber across a thin alumina substrate of proper acoustic impedance. The PZT substrate is sawed into an array of elements and a metal foil with an integrally moulded acoustic lens is bonded to the tops of the elements to form the common ground connection. The transducer stack is enclosed in an alumina box and the electrical connection to the PZT elements is made by silk-screened metallic conductors on the sides of the box. The stack transducer module is enclosed in a two part linen bakelite case which is sealed by injecting silicone rubber. A technique that was used to prepare the surface of the acoustic absorber, which resulted in wide bandwidth transducers, is described. Finally, we show the pulse-echo response of the completed transducer imaging a point target in water.

INFLUENCE OF THE INTER-ELEMENT COUPLING ON ULTRASOUND ARRAY RADIATION PATTERNS

2001 ◽  
Vol 09 (03) ◽  
pp. 773-788 ◽  
Author(s):  
P. GORI ◽  
A. IULA ◽  
M. PAPPALARDO ◽  
N. LAMBERTI ◽  
F. MONTERO DE ESPINOSA
Keyword(s):  
Radiation Pattern ◽  
Numerical Technique ◽  
Central Element ◽  
Cross Coupling ◽  
Filling Material ◽  
Radiation Patterns ◽  
Sommerfeld Integral ◽  
Array Transducer ◽  
Five Elements ◽  
The Cross

It is well known that the performances of the acoustic imaging arrays are degraded by the inter-element coupling sustained via the backing, the matching layers, and the kerf filler. The filling material inserted between the elements gives mechanical robustness to the array, but acts as a path of interaction, transmitting, between the elements, shear and lateral compressional forces. In this work, the effect on the array radiation pattern of the cross-coupling due to the filling material is investigated. A hybrid experimental–numerical technique is used. Two groups of five elements of a commercial array transducer were isolated and in one group the kerf filling material was removed. The cross-coupling waveforms, captured with a mechanical probe of small dimensions in contact with the emitting surfaces of the elements, were recorded for filled and unfilled groups of elements when: only the central element of the group was driven; all the elements were driven with the same pulse applied at the same time; all the elements were driven with the same pulse, but inverting the polarity alternately. This latter case refers to the worst coupling situation caused by the shear forces exerted between the elements. Fourier transforming the temporal signals, the cross-coupling transfer function of each element was computed and the radiation pattern was simulated by a numerical model based on the Rayleigh–Sommerfeld integral. Comparing the radiation patterns for filled and unfilled groups of elements, for the three cases mentioned above, a good estimation of the influence of the filling material is obtained.

scholarly journals Experimental Investigation of Inter-element Isolation in a Medical Array Transducer at Various Manufacturing Stages

2016 ◽  
Vol 39 (1) ◽  
pp. 62-74 ◽  
Author(s):  
Franco Marinozzi ◽  
Fabiano Bini ◽  
Andrea Grandoni
Keyword(s):  
Experimental Investigation ◽  
Lead Zirconate Titanate ◽  
Central Element ◽  
Laser Doppler Vibrometer ◽  
Cross Coupling ◽  
Lead Zirconate ◽  
Matching Layer ◽  
Array Transducer ◽  
Vibration Pattern ◽  
The One

This work presents the experimental investigation of vibration maps of a linear array transducer with 192 piezoelements by means of a laser Doppler vibrometer at various manufacturing finishing steps in air and in water. Over the years, many researchers have investigated cross-coupling in fabricated prototypes but not in arrays at various manufacturing stages. Only the central element of the array was driven at its working frequency of 5 MHz. The experimental results showed that the contributions of cross-coupling depend on the elements of the acoustic stack: Lead Zirconate Titanate (PZT), kerf, filler, matching layer, and lens. The oscillation amplitudes spanned from (6 ± 38%) nm to (110 ± 40%) nm when the energized element was tested in air and from (6 ± 57%) nm to (80 ± 67%) nm when measurements were obtained under water. The best inter-element isolation of −22 dB was measured in air after cutting the kerfs, whereas the poorest isolation was −2 dB under water with an acoustic lens (complete acoustic stack). The vibration pattern in water showed a higher standard deviation on the displacement measurements than the one obtained in air, due to the influence of acousto-optic interactions. The amount increased to 30% in water, as estimated by a comparison with the measurements in air. This work describes a valuable method for manufacturers to investigate the correspondence between the manufacturing process and the quantitative evaluations of the resulting effects.

A horizontal linear vibrator for measuring the cross-coupling coefficient of superconducting gravity gradiometers

Measurement ◽  
2021 ◽  
Vol 174 ◽  
pp. 109083
Author(s):  
Lu Zhang ◽  
Yuntao Qiu ◽  
Xikai Liu ◽  
Liang Chen ◽  
Ning Zhang ◽  
...  
Keyword(s):  
Coupling Coefficient ◽  
Cross Coupling ◽  
Superconducting Gravity ◽  
The Cross

scholarly journals Divergent Pathways Regulate Ligand-Independent Activation of ERα in SK-N-BE Neuroblastoma and COS-1 Renal Carcinoma Cells

1998 ◽  
Vol 12 (6) ◽  
pp. 835-841
Author(s):  
Cesare Patrone ◽  
Elisabetta Gianazza ◽  
Sabrina Santagati ◽  
Paola Agrati ◽  
Adriana Maggi
Keyword(s):  
Cell Line ◽  
Intracellular Signaling ◽  
Steroid Receptors ◽  
Neuroblastoma Cell ◽  
Cross Coupling ◽  
Activation Function ◽  
Neuroblastoma Cell Line ◽  
Membrane Receptors ◽  
Insulin Dependent ◽  
The Cross

Abstract The α-estrogen receptor (ERα) transcriptional activity can be regulated either by binding to the cognate ligand or by intracellular signaling pathways responsive to a variety of factors acting through cell membrane receptors. Studies carried out in HeLa and COS-1 cells demonstrated that the cross-coupling between estrogen and growth factor receptors is mediated by p21ras and requires phosphorylation of a specific serine residue (Ser 118 in the human ERα and Ser 122 in mouse ERα) located in the ERα N-terminal activation function 1 (AF-1). Likewise, in the SK-N-BE neuroblastoma cell line p21ras is involved in the cross-coupling between insulin and ERα receptors. However, in this cell line Ser 122 is not necessary for insulin-dependent activation of unliganded ERα. In addition, after insulin activation, the electrophoretic mobility associated to serine hyperphosphorylation of ERα in SK-N-BE and in COS-1 cells is different. Our study rules out the possibility of tyrosine phosporylation in unliganded ERα activation by means of transactivation studies of ERα tyrosine mutants and analysis of Tyr phosphorylation immunoreactivity. The two cofactors for steroid receptors RIP 140 and SRC-1 do not seem to be specifically involved in the insulin-induced ERα transactivation. The present study demonstrates the possibility of an alternative, cell-specific pathway of cross-coupling between intracellular and membrane receptors, which might be of importance for the understanding of the physiological significance of this mode of activation in the nervous system.

scholarly journals Acousto-Optic Cells with Phased-Array Transducers and Their Application in Systems of Optical Information Processing

Materials ◽  
2021 ◽  
Vol 14 (2) ◽  
pp. 451
Author(s):  
Vladimir Balakshy ◽  
Maxim Kupreychik ◽  
Sergey Mantsevich ◽  
Vladimir Molchanov
Keyword(s):  
Phased Array ◽  
Power Conversion ◽  
Experimental Studies ◽  
Acoustic Power ◽  
Acoustic Mode ◽  
Bragg Angle ◽  
Excitation Band ◽  
Acousto Optic Interaction ◽  
Array Transducer ◽  
New Type

This paper presents the results of theoretical and experimental studies of anisotropic acousto-optic interaction in a spatially periodical acoustic field created by a phased-array transducer with antiphase excitation of adjacent sections. In this case, contrary to the nonsectioned transducer, light diffraction is absent when the optical beam falls on the phased-array cell at the Bragg angle. However, the diffraction takes place at some other angles (called “optimal” here), which are situated on the opposite sides to the Bragg angle. Our calculations show that the diffraction efficiency can reach 100% at these optimal angles in spite of a noticeable acousto-optic phase mismatch. This kind of acousto-optic interaction possesses a number of interesting regularities which can be useful for designing acousto-optic devices of a new type. Our experiments were performed with a paratellurite (TeO2) cell in which a shear acoustic mode was excited at a 9∘ angle to the crystal plane (001). The piezoelectric transducer had to nine antiphase sections. The efficiency of electric to acoustic power conversion was 99% at the maximum frequency response, and the ultrasound excitation band extended from 70 to 160 MHz. The experiments have confirmed basic results of the theoretical analysis.

Sign in / Sign up

Export Citation Format

Share Document