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Efficient Driving of Piezoelectric Transducers Using a Biaxial Driving Technique.

Pichardo S, Silva RR, Rubel O, Curiel L - PLoS ONE (2015)

Bottom Line: More efficient operation reduces the electric power required to produce the desired bioeffect or contrast.Journal of Physics: Condensed Matter. 2014;26(13):135901.] suggested that driving transducers by applying orthogonal electric fields can significantly reduce the coercivity that opposes ferroelectric switching.The average (± s.d.) resonance frequency of the samples was 465.1 (± 1.5) kHz.

View Article: PubMed Central - PubMed

Affiliation: Thunder Bay Regional Research Institute, Thunder Bay, Ontario, Canada; Electrical Engineering, Lakehead University, Thunder Bay, Ontario, Canada.

ABSTRACT
Efficient driving of piezoelectric materials is desirable when operating transducers for biomedical applications such as high intensity focused ultrasound (HIFU) or ultrasound imaging. More efficient operation reduces the electric power required to produce the desired bioeffect or contrast. Our preliminary work [Cole et al. Journal of Physics: Condensed Matter. 2014;26(13):135901.] suggested that driving transducers by applying orthogonal electric fields can significantly reduce the coercivity that opposes ferroelectric switching. We present here the experimental validation of this biaxial driving technique using piezoelectric ceramics typically used in HIFU. A set of narrow-band transducers was fabricated with two sets of electrodes placed in an orthogonal configuration (following the propagation and the lateral mode). The geometry of the ceramic was chosen to have a resonance frequency similar for the propagation and the lateral mode. The average (± s.d.) resonance frequency of the samples was 465.1 (± 1.5) kHz. Experiments were conducted in which each pair of electrodes was driven independently and measurements of effective acoustic power were obtained using the radiation force method. The efficiency (acoustic/electric power) of the biaxial driving method was compared to the results obtained when driving the ceramic using electrodes placed only in the pole direction. Our results indicate that the biaxial method increases efficiency from 50% to 125% relative to the using a single electric field.

No MeSH data available.


Plots of WA (a), WE (b) and η (c) as a function of ϕ for all transducers (Tx.#) when driving each of the P and L electrodes at their individual resonance frequency.The plots of WA(ϕ) (a) and η(ϕ) (c) show the results for the “P+L” (−) driving technique compared to the “P” (⋅⋅⋅) electrodes only. The error bars indicate the standard deviation between 3 repetitions of the experiments for the same value of ϕ. The plot of WE(ϕ) (b) shows the individual effective electrical power for each of the electrodes P (WEP, ⋅⋅⋅), L (WEL,—--) and their sum P+L (WE, −) when driving both P and L electrodes simultaneously. When only the P electrodes were driven (not shown), the values of WEP and WEL were 2 W and 0 W, respectively.
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pone.0139178.g007: Plots of WA (a), WE (b) and η (c) as a function of ϕ for all transducers (Tx.#) when driving each of the P and L electrodes at their individual resonance frequency.The plots of WA(ϕ) (a) and η(ϕ) (c) show the results for the “P+L” (−) driving technique compared to the “P” (⋅⋅⋅) electrodes only. The error bars indicate the standard deviation between 3 repetitions of the experiments for the same value of ϕ. The plot of WE(ϕ) (b) shows the individual effective electrical power for each of the electrodes P (WEP, ⋅⋅⋅), L (WEL,—--) and their sum P+L (WE, −) when driving both P and L electrodes simultaneously. When only the P electrodes were driven (not shown), the values of WEP and WEL were 2 W and 0 W, respectively.

Mentions: Fig 6 shows plots of WA, WE, and η for a transducer sample where each of its P and L electrodes were driven at their individual resonance frequency. In contrast to the results seen when driving P and L electrode at the same frequency, no observable trend as a function of ϕ could be observed. Fig 7 show the ensemble of results of WA, WE and η for all the transducers. A constant increase in η was observed for transducers #1 and #2 when both electrodes were driven, but again no trend was observed and this gain was inferior to driving both electrodes at the same frequency. A summary of the results observed when driving electrodes P and L at their individual resonance frequency is included in Tables 2 and 3.


Efficient Driving of Piezoelectric Transducers Using a Biaxial Driving Technique.

Pichardo S, Silva RR, Rubel O, Curiel L - PLoS ONE (2015)

Plots of WA (a), WE (b) and η (c) as a function of ϕ for all transducers (Tx.#) when driving each of the P and L electrodes at their individual resonance frequency.The plots of WA(ϕ) (a) and η(ϕ) (c) show the results for the “P+L” (−) driving technique compared to the “P” (⋅⋅⋅) electrodes only. The error bars indicate the standard deviation between 3 repetitions of the experiments for the same value of ϕ. The plot of WE(ϕ) (b) shows the individual effective electrical power for each of the electrodes P (WEP, ⋅⋅⋅), L (WEL,—--) and their sum P+L (WE, −) when driving both P and L electrodes simultaneously. When only the P electrodes were driven (not shown), the values of WEP and WEL were 2 W and 0 W, respectively.
© Copyright Policy
Related In: Results  -  Collection

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Show All Figures
getmorefigures.php?uid=PMC4587744&req=5

pone.0139178.g007: Plots of WA (a), WE (b) and η (c) as a function of ϕ for all transducers (Tx.#) when driving each of the P and L electrodes at their individual resonance frequency.The plots of WA(ϕ) (a) and η(ϕ) (c) show the results for the “P+L” (−) driving technique compared to the “P” (⋅⋅⋅) electrodes only. The error bars indicate the standard deviation between 3 repetitions of the experiments for the same value of ϕ. The plot of WE(ϕ) (b) shows the individual effective electrical power for each of the electrodes P (WEP, ⋅⋅⋅), L (WEL,—--) and their sum P+L (WE, −) when driving both P and L electrodes simultaneously. When only the P electrodes were driven (not shown), the values of WEP and WEL were 2 W and 0 W, respectively.
Mentions: Fig 6 shows plots of WA, WE, and η for a transducer sample where each of its P and L electrodes were driven at their individual resonance frequency. In contrast to the results seen when driving P and L electrode at the same frequency, no observable trend as a function of ϕ could be observed. Fig 7 show the ensemble of results of WA, WE and η for all the transducers. A constant increase in η was observed for transducers #1 and #2 when both electrodes were driven, but again no trend was observed and this gain was inferior to driving both electrodes at the same frequency. A summary of the results observed when driving electrodes P and L at their individual resonance frequency is included in Tables 2 and 3.

Bottom Line: More efficient operation reduces the electric power required to produce the desired bioeffect or contrast.Journal of Physics: Condensed Matter. 2014;26(13):135901.] suggested that driving transducers by applying orthogonal electric fields can significantly reduce the coercivity that opposes ferroelectric switching.The average (± s.d.) resonance frequency of the samples was 465.1 (± 1.5) kHz.

View Article: PubMed Central - PubMed

Affiliation: Thunder Bay Regional Research Institute, Thunder Bay, Ontario, Canada; Electrical Engineering, Lakehead University, Thunder Bay, Ontario, Canada.

ABSTRACT
Efficient driving of piezoelectric materials is desirable when operating transducers for biomedical applications such as high intensity focused ultrasound (HIFU) or ultrasound imaging. More efficient operation reduces the electric power required to produce the desired bioeffect or contrast. Our preliminary work [Cole et al. Journal of Physics: Condensed Matter. 2014;26(13):135901.] suggested that driving transducers by applying orthogonal electric fields can significantly reduce the coercivity that opposes ferroelectric switching. We present here the experimental validation of this biaxial driving technique using piezoelectric ceramics typically used in HIFU. A set of narrow-band transducers was fabricated with two sets of electrodes placed in an orthogonal configuration (following the propagation and the lateral mode). The geometry of the ceramic was chosen to have a resonance frequency similar for the propagation and the lateral mode. The average (± s.d.) resonance frequency of the samples was 465.1 (± 1.5) kHz. Experiments were conducted in which each pair of electrodes was driven independently and measurements of effective acoustic power were obtained using the radiation force method. The efficiency (acoustic/electric power) of the biaxial driving method was compared to the results obtained when driving the ceramic using electrodes placed only in the pole direction. Our results indicate that the biaxial method increases efficiency from 50% to 125% relative to the using a single electric field.

No MeSH data available.