Fabrication and modeling of inversion layer ultrasonic transducers using LiNbO/sub 3/ single crystal

Zhou, Qifa; Cannata, J.M.; Huang, C.Z.; Guo, Hongkai; Marmarelis, Vasilis Z.; Shung, K. K.

doi:10.1109/ultsym.2003.1293576

Cited by 9 publications

(15 citation statements)

References 9 publications

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“…It has been extensively researched for its excellent ferroelectric, piezoelectric, dielectric, pyroelectric, electric-optical and nonlinear optical properties (Wang et al, 2008;Chen et al, 2007;Sarkisov et al, 2000). Now LiNbO 3 is a very significant material for optical applications, such as acoustic wave transducers, acoustic delay lines, acoustic filters, optical amplitude modulators, optical phase modulators, second-harmonic generators, Q-switches, beam deflectors, dielectric waveguides, memory elements, holographic data processing devices, and others (Kim et al, 2001;Zhen et al, 2003;Pham et al, 2005;Liu et al, 2002;Zhou et al, 2006). LiNbO 3 is a ferroelectric material which has the highest Curie temperature of about 1210 °C up to now and the largest spontaneous polarization of about 0.70 C/m 2 at room temperature.…”

Section: Introductionmentioning

confidence: 99%

Photovoltaic Effect in Ferroelectric LiNbO3 Single Crystal

Lu¹,

Zhao²,

Li³

2011

Ferroelectrics - Physical Effects

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Section: Introductionmentioning

confidence: 99%

Photovoltaic Effect in Ferroelectric LiNbO3 Single Crystal

Lu¹,

Zhao²,

Li³

2011

Ferroelectrics - Physical Effects

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“…Mention is made here of Saravanos and Heyliger (1995), Saravanos et al (1997), Ramirez et al (2006), and references therein. FEM has also been used to model ultrasound transducers (Lerch, 1990;Hossack and Hayward, 1991;McKeighen, 2001;Zhou et al, 2006). Time-domain schemes have been used to predict the performance of ultrasound transducers in terms of impedances and efficiencies.…”

Section: Introductionmentioning

confidence: 99%

“…Time-domain schemes have been used to predict the performance of ultrasound transducers in terms of impedances and efficiencies. The effect of matching layers, backing layers, bonding layer and electrodes on the operation of the transducer can be addressed using this technique (Zhou et al, 2006;McKeighen, 2001). However, a large number of elements and simulation time are usually required for high frequency simulations.…”

Section: Introductionmentioning

confidence: 99%

“…A recent improvement on the design of broadband ultrasound transducer by the introduction of an inversion layer (IL) has been reported (Nakamura et al, 2003(Nakamura et al, , 2005Zhou et al, 2006Zhou et al, , 2005Huang et al, 2005). The active element in an IL transducer is composed of two piezoelectric sublayers of opposite poling directions.…”

Section: Introductionmentioning

confidence: 99%

“…It has been demonstrated that the use of a layer of LiNbO 3 of 30% of the total thickness with inverted piezoelectric properties decreases the conversion loss at the second-order thickness-mode, i.e., at a frequency equal to twice the fundamental resonance frequency. Zhou et al (2005Zhou et al ( , 2006 used time-domain finite elements to study electrical impedance and acoustic characteristics of IL transducers.…”

Section: Introductionmentioning

confidence: 99%

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Dispersion of elastic guided waves in piezoelectric infinite plates with inversion layers

Cortés

Datta

Mukdadi

2008

International Journal of Solids and Structures

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a b s t r a c tIn this work, we study the dispersion of elastic waves in piezoelectric infinite plates with ferroelectric inversion layers. The motivation is to analyze the effect of ferroelectric inversion layers on wave dispersion and resonant behavior under impulsive line loads. A semianalytical finite-element (SAFE) method has been adopted to analyze the problem. Two model problems are considered for analysis. In one, the plate is composed of a layer of 36°rotated y-cut LiNbO 3 with a ferroelectric inversion layer. In the other, material is PZT-4 with a ferroelectric inversion layer. Comparison with experimental results, reported in the literature for isotropic materials, shows a very good agreement with theoretical predictions obtained using SAFE method. Furthermore, comparison of the resonance frequencies of the S 1 modes, calculated using KLM approximation (f 0 = C d /2h) and SAFE method, are illustrated for each problem. The frequency spectra of the surface displacements show that resonant peaks occur at frequencies where the group velocity vanishes and the phase velocity remains finite, i.e., a minimum in the dispersion curve below the cut-off frequency. The effect of the ratio of the thicknesses of the inversion layer (IL) and the plate on the frequencies and strength of the resonant peaks is examined. It is observed that for PZT-4 with 50% IL to plate thickness ratio the frequency for the second resonant peak is about twice that for the first one. Results are presented showing the dependence of resonant frequencies on the material properties and anisotropy. Materials selection for single-element harmonic ultrasound transducers is a very important factor for optimum design of transducers with multiple thickness-mode resonant frequencies. The theoretical analysis presented in this study should provide a means for optimum ultrasound transducer design for harmonic imaging in medical applications.

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High‐frequency ultrasound transducer by using inversion layer technique for intravascular ultrasound imaging

Sung

Jeong

2016

Electron. lett.

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Inversion layer technique can increase the centre frequency ( f 0 ) and the −6 dB bandwidth of the ultrasound transducer without reducing thickness of active material. However, it suffers from the reduced −6 dB bandwidth when the centre frequency is increased more than 1.5f 0 . A modified inversion technique is proposed and applied it to high-frequency intravascular ultrasound (IVUS) transducer. The performance was computationally verified by using finite element method (FEM) simulation. The proposed IVUS transducer consists of two subelements with each aperture size of 0.6 × 0.6 mm, and each subelement has different types of inversion layer using PMN-PT and PZT-5H. The initial thickness of overall active material was designed for 40 MHz centre frequency and the FEM simulation showed that the centre frequency was increased by about 1.8f 0 maintaining the −6 dB fractional bandwidth compared with the conventional transducer.Introduction: In intravascular ultrasound (IVUS) imaging using a single element transducer, a high-frequency ultrasound (more than 20 MHz frequency) generated by a miniaturised aperture (<1 mm diameter) is directly transmitted to a blood vessel to display interior vessel structure [1]. To improve the resolution of ultrasound image in terms of the ultrasound transducer, the centre frequency and frequency bandwidth should be increased. To increase the centre frequency of the ultrasound transducer, the thickness of the active piezoelectric material should be thinned; however, it suffers from reduction of piezoelectric effect and fragile characteristic during fabrication. Additionally, because piezoelectric material vibrates only in odd-order thickness excitation mode, there is limitation to increase frequency bandwidth. One of the methods to overcome aforementioned issues is using the inversion layer technique [2][3][4][5]. In this technique, the centre frequency can be increased by changing location or ratio of inverted-piezoelectric layer while maintaining the total thickness of active material. However, it suffers from the reduced −6 dB bandwidth when the centre frequency is increased more than 1.5f 0 . In this Letter, we proposed the modified inversion technique capable of increasing the centre frequency more than 1.5f 0 without sacrificing the bandwidth. The proposed IVUS transducer is composed of two sub-elements based on different inversion ratios and different piezoelectric materials. The finite element method (FEM) simulation was conducted to demonstrate the performance of the proposed transducer and compared with the conventional transducer.

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Fabrication and modeling of inversion layer ultrasonic transducers using LiNbO/sub 3/ single crystal

Cited by 9 publications

References 9 publications

Photovoltaic Effect in Ferroelectric LiNbO3 Single Crystal

Photovoltaic Effect in Ferroelectric LiNbO3 Single Crystal

Dispersion of elastic guided waves in piezoelectric infinite plates with inversion layers

High‐frequency ultrasound transducer by using inversion layer technique for intravascular ultrasound imaging

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