Characteristics of wide-band planar ultrasonic transducers using plane and edge wave contributions

1988 ◽  
Vol 35 (2) ◽  
pp. 253-263 ◽  
Author(s):  
S.M. Kramer ◽  
S.L. McBride ◽  
H.D. Mair ◽  
D.A. Hutchins
Keyword(s):  
Wide Band ◽  
Ultrasonic Transducers ◽  
Edge Wave

Comparative study of wide-band ultrasonic transducers

Ultrasonics ◽  
1987 ◽  
Vol 25 (6) ◽  
pp. 315-321 ◽  
Author(s):  
R.J. Dewhurst ◽  
C.E. Edwards ◽  
A.D.W. McKie ◽  
S.B. Palmer
Keyword(s):  
Comparative Study ◽  
Wide Band ◽  
Ultrasonic Transducers

scholarly journals Ferroelectret Ultrasonic Transducers for Pulse-Echo Water Immersion

2020 ◽  
Vol 10 (24) ◽  
pp. 8771
Author(s):  
Julio Quirce ◽  
Linas Svilainis ◽  
Jorge Camacho ◽  
Tomas Gomez Alvarez-Arenas
Keyword(s):  
Short Pulse ◽  
Water Immersion ◽  
Wide Band ◽  
Spot Size ◽  
Ultrasonic Transducers ◽  
Piezoelectric Response ◽  
Radius Of Curvature ◽  
High Porosity ◽  
Technical Problems ◽  
Pulse Echo

Ferroelectrets are thin and porous polymeric films with a cellular microstructure, high porosity, permanent polarization and piezoelectric response. They have been used for different applications, where one of the most interesting ones is for the fabrication of air-coupled ultrasonic transducers. More recently they have been tested as water immersion transducers, showing a promising wide bandwidth but limited sensitivity along with other technical problems. This paper investigates ultrasonic transducers for water immersion and pulse-echo operation based on ferroelectret films. Two different ferroelectret foams with different resonant frequencies, acoustic impedances and cellular structures were tried. Flat and spherically focused prototypes (radius of curvature of 22 and 35 mm) were produced and tested. Finally, different materials and methods were tried to provide a protective surface coating. Acoustic field measurements for the focused transducers confirm the possibility to efficiently focus the ultrasonic beam by the proposed fabrication method, with focal spot size of 1.86 mm at −6 dB. Results show that in spite of the reduced sensitivity (about −115 dB), some of the tried ferroelectret films provide a very wide band response (−6 dB band from 0.29 to 2.7 MHz) and short pulse duration (2–3 us) that can be of interest for different applications.

Fabrication of non-uniformly excited wide-band ultrasonic transducers

Ultrasonics ◽  
1987 ◽  
Vol 25 (2) ◽  
pp. 100-106 ◽  
Author(s):  
R.H. Brittain ◽  
J.P. Weight
Keyword(s):  
Wide Band ◽  
Ultrasonic Transducers

Wide-band Multi-layer Ultrasonic Transducers Made of Piezoelectric Films of Vinylidene Fluoride-Trifluoroethylene Copolymer

1986 ◽  
Vol 25 (S1) ◽  
pp. 91 ◽  
Author(s):  
Kousaku Sakaguchi ◽  
Takashi Sato ◽  
Kiyohito Koyama ◽  
Susumu Ikeda ◽  
Shuichiro Yamamizu ◽  
...  
Keyword(s):  
Vinylidene Fluoride ◽  
Wide Band ◽  
Ultrasonic Transducers ◽  
Piezoelectric Films

Seven-colour photometry at the Geneva Observatory

1966 ◽  
Vol 24 ◽  
pp. 262-266 ◽  
Author(s):  
M. Golay
Keyword(s):  
Wide Band ◽  
Electric System ◽  
Band Type

During the last 5 years, we have developed a seven-colour photometry at the Geneva Observatory. Our multicolour photo-electric system is of a wide-band type; the bandwidth being about 500Å for four filters. The three others are similar to theUBVsystem. In Table 1 we give the filter combinations used in our photometry (1).

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