A casting-based fabrication process for a high-frequency piezo-electric linear array

2012 ◽  
Author(s):  
Gerrit J. van Dijk ◽  
Erwin J. Alles ◽  
Koen W.A. van Dongen
Keyword(s):  
High Frequency ◽  
Linear Array ◽  
Fabrication Process ◽  
Piezo Electric

scholarly journals Accuracy of ultrasonography in detecting radiolucent soft-tissue foreign bodies

2014 ◽  
Vol 24 (02) ◽  
pp. 196-200
Author(s):  
Morteza Tahmasebi ◽  
Hamdollah Zareizadeh ◽  
Azim Motamedfar
Keyword(s):  
Foreign Body ◽  
Soft Tissue ◽  
High Frequency ◽  
Foreign Bodies ◽  
Linear Array ◽  
Foreign Body Removal ◽  
Retained Foreign Body ◽  
Array Transducer ◽  
Highly Sensitive ◽  
Objective Detection

Abstract Background and Objective: Detection of radiolucent soft-tissue foreign bodies is a challenging problem, which is especially further complicated when retained foreign body is highly suggested by clinicians but radiography is negative. So, blind exploration is sometimes hazardous for patients. The purpose of this study was to determine the accuracy of ultrasonography (USG) in detecting radiolucent soft-tissue foreign bodies in the extremities. Materials and Methods: From November 2011 to January 2012, patients with clinically suspected radiolucent soft-tissue foreign body and negative radiography were evaluated by USG with a 12-MHz linear array transducer. The patients with positive clinical and USG examination were included in our study and underwent exploration or USG removal. Results: Fifty-one patients underwent foreign body removal under ultrasonography-guided or surgical exploration and 47 patients had foreign body (31, 12, 3, and 1 case had thorn, wood, glass, and plastic, respectively). Ultrasound was positive in 50 patients. USG falsely predicted the presence of foreign body in four cases and was falsely negative in one of the cases. Accuracy, sensitivity, and positive predictive value were determined as 90.2%, 97.9%, and 92%, respectively. Conclusions: The real-time high-frequency USG is a highly sensitive and accurate tool for detecting and removing radiolucent foreign bodies which are difficult to be visualized by routine radiography.

Design and fabrication of high frequency BNT film based linear array transducer

2015 ◽  
Vol 41 ◽  
pp. S631-S637 ◽  
Author(s):  
Hongwei Liu ◽  
Wei Ren ◽  
Jinyan Zhao ◽  
Huifeng Zhao ◽  
Xiaoqing Wu ◽  
...  
Keyword(s):  
High Frequency ◽  
Linear Array ◽  
Array Transducer

scholarly journals New fabrication of high-frequency (100-MHz) ultrasound PZT film kerfless linear array [Correspondence]

2013 ◽  
Vol 60 (4) ◽  
pp. 854-857 ◽  
Author(s):  
Benpeng Zhu ◽  
Ngai Yui Chan ◽  
Jiyan Dai ◽  
K. Kirk Shung ◽  
Shinichi Takeuchi ◽  
...  
Keyword(s):  
High Frequency ◽  
Linear Array ◽  
Pzt Film

scholarly journals High-Frequency Radars: Beamforming Calibrations Using Ships as Reflectors*

2013 ◽  
Vol 30 (3) ◽  
pp. 638-648 ◽  
Author(s):  
X. Flores-Vidal ◽  
P. Flament ◽  
R. Durazo ◽  
C. Chavanne ◽  
K.-W. Gurgel
Keyword(s):  
High Frequency ◽  
Unusual Case ◽  
Linear Array ◽  
Beam Steering ◽  
Surface Current ◽  
Calibration Procedure ◽  
Beam Pattern ◽  
Dramatic Improvement ◽  
Ocean Surface Current ◽  
Phase Differences

Abstract Linear array antennas and beamforming techniques offer some advantages compared to direction finding using squared arrays. The azimuthal resolution depends on the number of antenna elements and their spacing. Assuming an ideal beam pattern and no amplitude taper across the aperture, 16 antennas in a linear array spaced at half the electromagnetic wavelength theoretically provide a beam resolution of 3.5° normal to the array, and up to twice that when the beam is steered within an azimuthal range of 60° from the direction normal to the array. However, miscalibrated phases among antenna elements, cables, and receivers (e.g., caused by service activities without recalibration) can cause errors in the beam-steering direction and distortions of the beam pattern, resulting in unreliable ocean surface current and wave estimations. The present work uses opportunistic ship echoes randomly received by oceanographic high-frequency radars to correct an unusual case of severe phase differences between receiver channels, leading to a dramatic improvement of the surface current patterns. The method proposed allows for simplified calibrations of phases to account for hardware-related changes without the need to conduct the regular calibration procedure and can be applied during postprocessing of datasets acquired with insufficient calibration.

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