PVDF ultrasonic transducers

Platte, Michael

doi:10.1080/00150198708008983

Cited by 33 publications

(16 citation statements)

References 13 publications

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“…It is a unique polymer and its ferroelectric behavior combined with its superb mechanical properties and ease of fabrication makes it more useful for piezoelectric and pyroelectric applications. PVDF is serious contender with its more conventional ceramic counterpart and exhibits advantages over it for use as hydrophones and also in the design of new transducers especially a needle type hydrophones [6]. Recently, the characterization of PVDF membranes with porous structures [7] and dielectric behavior of PVDF blend [8] have been reported.…”

Section: Introductionmentioning

confidence: 99%

AC Conductivity and Dielectric Relaxation Behavior of Solution Grown Poly (Vinylidene Fluoride) Films

Singh

Sinha²,

Kaur

et al. 2005

Ferroelectrics

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Ac conductivity [σ m (ω)], dielectric constant [ε (ω)] and dielectric loss [ε (ω)] of solution grown poly (vinylidene fluoride) (PVDF) films (thick ∼85-100 µm) have been measured in the temperature range 77-400 K and in the frequency range 100 HZ-10 MHz. A frequency dependent conductivity described by the relation σ (ω) = Aω s , is observed in the low temperature region where s < 1 and is independent of temperature up to 200 K and decreases with increase in temperature. The density of states at the Fermi level [N (E F )] estimated at 77 K and 100 kHz is ∼1.1×10 18 −4.8×10 19 cm −3 eV −1 . The dielectric constant in the low temperature region (<200 K) shows a very weak frequency and temperature dependence. However, in the higher temperature region (>250 K) a strong frequency dispersion of dielectric constant and strong temperature dependence of ac conductivity are observed. Three relaxations; the α c − , the α a − and the β-relaxations, appearing from high temperature side to the low temperature side in the dielectric loss versus temperature spectrum, having activation energy ∼0.232-0.474 eV, ∼0.189-0.226 eV and ∼ 0.052-0.068 eV, respectively have been observed in the present investigation. The activation energies (∼0.02-0.05 eV) of the charge carriers calculated at 77 K indicates the evidence of electronic hopping conduction in the low temperature region.

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Section: Introductionmentioning

confidence: 99%

AC Conductivity and Dielectric Relaxation Behavior of Solution Grown Poly (Vinylidene Fluoride) Films

Singh

Sinha²,

Kaur

et al. 2005

Ferroelectrics

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“…The bandwidth of the resulting ultrasonic channel was shown to be much greater than narrowband transducers allow, even at room-scale distances and for transmitter and receiver units not directly facing one another. 16. Accuracy of location estimates in the privacy-oriented system.…”

Section: Resultsmentioning

confidence: 99%

“…These piezo films, most notably polyvinylidene fluoride (PVDF), have been applied as ultrasonic transducers in hydrophone applications, and for high frequency (greater than 200 kHz) medical imaging and nondestructive testing [15], [16], [17], [18]. Piezo film transducers are small, inexpensive, more rugged than electrostatic transducers, and have a wide frequency bandwidth.…”

Section: Transducer Selection and Mountingmentioning

confidence: 99%

Broadband ultrasonic location systems for improved indoor positioning

Hazas

Hopper

2006

IEEE Trans. on Mobile Comput.

337

178

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Ultrasonic location systems are a popular solution for the provision of fine-grained indoor positioning data. Applications include enhanced routing for wireless networks, computer-aided navigation, and location-sensitive device behavior. However, current ultrasonic location systems suffer from limitations due to their use of narrowband transducers. This paper investigates the use of broadband ultrasound for indoor positioning systems. Broadband ultrasonic transmitter and receiver units have been developed and characterized. The utilization of these units to construct two positioning systems with different architectures serves to highlight and affirm the concrete, practical benefits of broadband ultrasound for locating people and devices indoors.Index Terms-Location-dependent/sensitive, pervasive and ubiquitous computing, support services for mobile computing. ae 536

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“…Electrostatic or capacitance devices [6] consist of a roughened conducting backplate electrode over which a metallized membrane is stretched. There are also several piezoelectric designs, which use piezopolymer foils such as PVDF [7], impedance matching layers [8], or composites of epoxy resin and piezoceramics such as PZT [9]. SUGh a device is used in this work, and is based on a 1-3 connectivity composite [10], shown schematically in Figure 1.…”

Section: Introductionmentioning

confidence: 99%