共查询到20条相似文献,搜索用时 27 毫秒
1.
Zhou Q Xu X Gottlieb EJ Sun L Cannata JM Ameri H Humayun MS Han P Shung KK 《IEEE transactions on ultrasonics, ferroelectrics, and frequency control》2007,54(3):668-675
High-frequency needle ultrasound transducers with an aperture size of 0.4 mm were fabricated using lead magnesium niobate-lead titanate (PMN-33% PT) as the active piezoelectric material. The active element was bonded to a conductive silver particle matching layer and a conductive epoxy backing through direct contact curing. An outer matching layer of parylene was formed by vapor deposition. The active element was housed within a polyimide tube and a 20-gauge needle housing. The magnitude and phase of the electrical impedance of the transducer were 47 omega and -38 degrees, respectively. The measured center frequency and -6 dB fractional bandwidth of the PMN-PT needle transducer were 44 MHz and 45%, respectively. The two-way insertion loss was approximately 15 dB. In vivo high-frequency, pulsed-wave Doppler patterns of blood flow in the posterior portion and in vitro ultrasonic backscatter microscope (UBM) images of the rabbit eye were obtained with the 44-MHz needle transducer. 相似文献
2.
Saitoh S Takeuchi T Kobayashi T Harada K Shimanuki S Yamashita Y 《IEEE transactions on ultrasonics, ferroelectrics, and frequency control》1999,46(2):414-421
A novel 128-channel phased array probe for echocardiography with a center frequency of 3.7 MHz using 0.91Pb(Zn(1/3)Nb(2/3))O(3)-0.09PbTiO(3 ) (PZN-9%PT) single crystal has been fabricated to realize greater sensitivity and broader bandwidth properties. The echo amplitude of the PZN-9%PT single-crystal probe is about 5 dB higher than that of the conventional lead airconate titanate (PZT) ceramic probe, and the fractional bandwidth is about 25 percentage points broader. The quality of B mode images obtained by the PZN-9%PT probe satisfies the performance of the two types of conventional PZT ceramic probes that have center frequencies of 2.5 and 3.75 MHz. At the reference frequency of 3 MHz, the Doppler sensitivity of the PZN-9%PT probe is about 5 dB higher than that of the 3.75 MHz PZT probe; the blood flow of a pulmonary vein in a hard-to-image patient is much more clearly imaged than in the case of using the PZT probe. These superior images are attributable to the use of sufficiently large PZN-9%PT single crystals obtained by the self-flux method. 相似文献
3.
He C Jing W Zhu K Qiu J 《IEEE transactions on ultrasonics, ferroelectrics, and frequency control》2011,58(6):1118-1121
The optical transmittance spectra of relaxor ferroelectric 0.92Pb(Zn(1/3)Nb(2/3))O(3)-0.08PbTiO(3) (PZN-8%PT) single crystals poled along different directions have been systematically studied at room temperature. After being poled along the [011] direction, the transmittance of induced orthorhombic PZN-8%PT single crystal is more than 50% from 0.5 to 5.7 μm, which is much higher than that poled along the [001] and [111] directions. The refractive indices and linear electro-optic properties of the orthorhombic PZN-8%PT single crystal were characterized at a wavelength of 632.8 nm. Large electro-optic responses were observed, (γ33) = 220 pm/V, (γ13) = 62 pm/V, and (γ23) = 23 pm/V. Thus, orthorhombic PZN-8%PT single crystal is a promising material for high-performance electro-optic devices. 相似文献
4.
Yin J Jiang B Cao W 《IEEE transactions on ultrasonics, ferroelectrics, and frequency control》2000,47(1):285-291
The elastic, piezoelectric, and dielectric properties of a 0.955Pb(Zn(1/3)Nb(2/3))O(3)-0.045PbTiO(3 ) (PZN-4.5%PT) multi-domain single crystal, poled along [001] of the original cubic direction, have been determined experimentally using combined resonance and ultrasonic methods. At room temperature, the PZN-4.5%PT single crystal has rhombohedral symmetry. After being poled along [001], four degenerate states still remain. Statistically, such a domain-engineered crystal may be treated as having an average tetragonal symmetry, and its material constants were determined based on 4 mm symmetry. It was confirmed that the electromechanical coupling coefficient k(33) for the domain-engineered samples is >90%, and the piezoelectric constant d(33) is >2000 pC/N. A soft shear mode with a velocity of 700 m/s was found in the [110] direction. From the measured experimental data, the orientational dependence of phase velocities and electromechanical coupling coefficients was calculated. The results showed that the transverse and longitudinal coupling coefficients, k(31) and k(33), reach their maximum along [110] and [001], respectively. 相似文献
5.
Kumar FJ Lim LC Lim SP Lee KH 《IEEE transactions on ultrasonics, ferroelectrics, and frequency control》2003,50(3):203-209
A nondestructive quality evaluation and control procedure for large-area, (001)-cut PZN-8%PT wafers is described. The crystals were grown by the flux technique engineered to promote (001) layer growth of the crystals. The wafers were sliced parallel to the (001) layer growth plane. Curie temperature (Tc) variations, measured with matching arrays of dot electrodes (of 5.0 mm in center-to-center spacing), were found to be better than +/- 4.0 degrees C both within wafers and from wafer to wafer. After selective dicing to give final wafers of narrower Tc distributions (e.g., +/- 3.0 degrees C or better), the wafers were coated with complete electrodes and poled at room temperature at 0.7-0.9 kV/mm. Typical overall properties of the poled wafers were: K3T = 5,200 (+/- 10% from wafer to wafer), tan delta < 0.01 (all wafers), and kt = 0.55 (+/- 5%) (all percentage variations are in relative percentages). Then, the distributions of K3S, tan delta, and kt were measured by the array dot electrode technique. The variations in K3S (hence K3T) and kt within individual wafers were found to be within +/- 10% and +/- 5%, respectively. The dielectric loss values, measured at 1 kHz, were consistently low, being < 0.01 throughout the wafers. The kt values determined by the dot electrodes were found to be about 5% smaller than those obtained with the complete electrodes, which can be attributed to an increase in capacitance ratio due to the partial electroding. The k33 values, deduced using the relation K3S approximately (1 - k33(2))K3T, from the mean K3S and overall K3T values, average 0.94 (+/- 2%). The present work shows that the distribution of Tc within wafers can be used as a convenient check for the uniformity in composition and electromechanical properties of PZN-8%PT single crystal wafers. Our results show that, to control deltaK3T and deltakt within individual wafer to < or = 10% and 5%, respectively, the variation in Tc within the wafer should be kept within +/- 3.0 degrees C or better. 相似文献
6.
He C Jing W Wang F Zhu K Qiu J 《IEEE transactions on ultrasonics, ferroelectrics, and frequency control》2011,58(6):1127-1130
Transverse piezoelectric property of 0.91Pb(Zn(1/3)Nb(2/3))O(3)-0.09PbTiO(3) (PZN-9%PT) single crystal poled along [011] direction under different fields have been investigated, the poling field giving the best property was between 350 and 650 V/mm at room temperature. Full tensorial elastic, dielectric, and piezoelectric properties of PZN-9%PT single crystal poled along the [011] direction under 500 V/mm have been determined by resonance and ultrasonic methods. It was found that the electromechanical coupling coefficients k(32) and k(33) can reach 0.90 and 0.89 and the piezoelectric coefficients d(32) and d(15) are -1705 and 2012 pC/N, respectively. This complete set of physical properties can provide convenience for piezoelectric device fabrication and domain engineering studies. 相似文献
7.
Fabrication and performance of a 40-MHz linear array based on a 1-3 composite with geometric elevation focusing 总被引:1,自引:0,他引:1
Brown JA Foster FS Needles A Cherin E Lockwood GR 《IEEE transactions on ultrasonics, ferroelectrics, and frequency control》2007,54(9):1888-1894
The fabrication and performance of a 256-element high-frequency (40-MHz) linear array is described. The array was fabricated using a high-frequency 1-3 PZT-polymer composite material developed in our laboratory. The spacing of the pillars in the composite was chosen to match the 40-microm center-to-center element spacing of the array electrodes. The element electrodes were created using photolithography, and connections to the electrodes were made using ultrasonic wire bonding. The array was focused in the elevation direction by geometrically shaping the composite material using a cylindrical die with a 6-mm radius of curvature. The resulting transducer produced pulses with a -6 dB two-way bandwidth of 50% and a peak-to-peak pressure of 503 kPa when excited with a +/-30 V monocycle pulse. The measured one-way (-6 dB) directivity for a single array element was 24 degrees and the -3 dB one-way elevation beamwidth was measured to be 130 microm. The radiation pattern for a focused 64-element subaperture was measured by mechanically translating the aperture above a needle hydrophone. A -3 dB one-way beamwidth of 97 microm was found at a depth of 6 mm. The one-way radiation pattern decreased smoothly to less than -30 dB at a lateral distance of 640 microm. 相似文献
8.
Lee W Idriss SF Wolf PD Smith SW 《IEEE transactions on ultrasonics, ferroelectrics, and frequency control》2004,51(10):1334-1346
The design, fabrication, and characterization of a 112 channel, 5 MHz, two-dimensional (2-D) array transducer constructed on a six layer flexible polyimide interconnect circuit is described. The transducer was mounted in a 7 Fr (2.33 mm outside diameter) catheter for use in real-time intracardiac volumetric imaging. Two transducers were constructed: one with a single silver epoxy matching layer and the other without a matching layer. The center frequency and -6 dB fractional bandwidth of the transducer with a matching layer were 4.9 MHz and 31%, respectively. The 50 omega pitch-catch insertion loss was 80 dB, and the typical interelement crosstalk was -30 dB. The final element yield was greater than 97% for both transducers. The transducers were used to acquire real-time, 3-D images in an in vivo sheep model. We present in vivo images of cardiac anatomy obtained from within the coronary sinus, including the left and right atria, aorta, coronary arteries, and pulmonary veins. We also present images showing the manipulation of a separate electrophysiological catheter into the coronary sinus. 相似文献
9.
Lim LC Rajan KK Jin J 《IEEE transactions on ultrasonics, ferroelectrics, and frequency control》2007,54(12):2474-2478
Relaxor ferroelectric Pb(Zn(1/3)Nb(2/3))O(3-x)PbTiO(3) (PZN-PT) and Pb(Mg(1/3)Nb(2/3))O(3)-PbTiO(3)(PMN-PT) single crystals are the potential candidates for future high-performance piezoelectric devices due to their exceptionally high dielectric and piezoelectric properties. Characterization on flux-grown PZN-PT single crystals of different orientations revealed that PZN-(6-7)%PT single crystals show good homogeneity in dielectric and electromechanical properties and composition. When poled in [001] direction, these crystals exhibit high longitudinal-mode properties with dielectric constant (K(T)) approximately equal to 7000, piezoelectric coefficients (d(33)) approximately equal to 2800 pC/N, and electromechanical coupling factors (k(33)) > or = 0.92. For [011]-cut crystals, optimally poled PZN-7%PT single crystal exhibits very high transverse-mode dielectric and piezoelectric properties with K(T) > or = 5000, d(32) approximately equal to -3800 pC/N and k(32) > or = 0.90. [011]- poled PZN 6%PT has d(32) approximately equal to -3000 pC/N and comparable k(32) and K(T) values. In comparison with melt-grown PMNPT single crystals, flux-grown PZN-PT single crystals show good compositional homogeneity, superior and consistent dielectric and electromechanical properties, and higher depolarization temperatures (TDP). 相似文献
10.
Delaunay T Clezio EL Guennou M Dammak H Thi MP Feuillard G 《IEEE transactions on ultrasonics, ferroelectrics, and frequency control》2008,55(2):476-488
An experimental setup based on the electrical excitation of a piezoelectric sample is proposed for resonant ultrasound spectroscopy measurements. The detection of the mechanical vibrations is performed by means of a laser interferometer. At the same time, the free vibrations of piezoelectric parallelepipeds of tetragonal and hexagonal symmetries are modeled taking into account the effect of the sample metalization. The paper presents the full elastic, piezoelectric and dielectric tensors of two PMN-34.5%PT ceramic and PZN-12%PT single crystal cubes. 相似文献
11.
Cannata JM Williams JA Zhou QF Sun L Shung KK Yu H Kim ES 《Journal of applied physics》2008,103(8):artno084109
A simple fabrication technique was developed to produce high frequency (100 MHz) self-focused single element transducers with sputtered zinc oxide (ZnO) crystal films. This technique requires the sputtering of a ZnO film directly onto a curved backing substrate. Transducers were fabricated by sputtering an 18 μm thick ZnO layer on 2 mm diameter aluminum rods with ends shaped and polished to produce a 2 mm focus or f-number equal to one. The aluminum rod served a dual purpose as the backing layer and positive electrode for the resultant transducers. A 4 μm Parylene matching layer was deposited on the transducers after housing and interconnect. This matching layer was used to protect the substrate and condition the transfer of acoustic energy between the ZnO film and the load medium. The pulse-echo response for a representative transducer was centered at 101 MHz with a -6 dB bandwidth of 49%. The measured two way insertion loss was 44 dB. A tungsten wire phantom and an adult zebrafish eye were imaged to show the capability of these transducers. 相似文献
12.
Ritter T Geng X Kirk Shung K Lopath PD Park SE Shrout TR 《IEEE transactions on ultrasonics, ferroelectrics, and frequency control》2000,47(4):792-800
Single crystal relaxor ferroelectrics of PZN-8%PT were investigated for potential application in ultrasound transducers. The full set of electromechanical properties was determined using combined resonance and laser interferometry techniques. Ultra-high length extensional coupling (k(33)) of 0.94 was observed, a 25% increase over Navy Type VI PZT ceramics. The thickness extensional coupling (k(t)) of 0.48 was comparable to PZT compositions, and the compliance S(33)(E) was a factor of six greater. To maximize height extensional coupling (k'(33)), while minimizing length extensional coupling k(31) in array elements, it was necessary to align the elements along the 100 crystallographic direction in the x-y plane. Mode coupling plots and test samples for array elements determined that width-to-height ratios of less than 0.5 were desired, similar to the requirement for polycrystalline PZT ceramics. Modeling of 1-3 composites and experimental results demonstrated that thickness coupling greater than 0.80 could be achieved with a 40% to 70% volume fraction of PZN-PT. Although this is a substantial increase over PZT 1-3 composites, with a thickness coupling coefficient of 0.66, it represents a smaller fraction of the length extensional coupling k(33). This reduction may be a consequence of the increased compliance of PZN-PT, which results in significant clamping by the polymer matrix. Ultrasonic transducers fabricated using PZN-8%PT 1-3 composites achieved experimental bandwidths as high as 141%. The pulse-echo responses displayed good agreement with modeled results using the Redwood equivalent circuit. 相似文献
13.
Zhang Y Zhao X Wang W Ren B Liu D Luo H 《IEEE transactions on ultrasonics, ferroelectrics, and frequency control》2011,58(9):1774-1781
In this paper, PIMNT/epoxy 1-3 composites with different volume fractions were prepared by the dice-and-fill method for application in ultrasonic transducers. The theoretical and experimental properties at different volume fractions and the temperature stability of the electromechanical property were investigated. The highest electromechanical coupling factor k(t) was obtained as 0.833 with the volume fraction of 0.58 and k(t) changed little below the Curie temperature of the single crystal. Afterward, an angle-beam transverse wave ultrasonic transducer using the fabricated composite was designed and manufactured based on the simulation of the KLM model and commercial software. The assembled prototype transducer showed large improvement in two-way insertion loss, relative bandwidth at -6 dB, surplus sensitivity, and axial resolution, which were -24.3 dB, 107%, 85 dB, and 28 dB, respectively, compared with a commercial PZT-based composite transducer. 相似文献
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16.
Chen Y Jiang XP Luo HS Dai JY Chan HL 《IEEE transactions on ultrasonics, ferroelectrics, and frequency control》2010,57(11):2601-2604
High-frequency (25 MHz) ultrasonic transducers with Na(0.5)Bi(0.5)TiO(3)-BaTiO(3) (NBT-BT) lead-free piezoelectric single crystal as the active elements are fabricated and characterized. The impedance measurement reveals that the poled [001]-oriented NBT-BT single crystal exhibits a high thickness electromechanical coefficient k(t) of 0.52 and a low clamped dielectric constant of 80. The -6-dB bandwidth of the transducer is 46.16% and the insertion loss at the center frequency is -31.89 dB. The good performance of the transducer indicates that the NBT-BT single crystal would be a promising lead-free material for ultrasonic transducer applications. 相似文献
17.
Vos HJ Frijlink ME Droog E Goertz DE Blacquière G Gisolf A de Jong N van der Steen AF 《IEEE transactions on ultrasonics, ferroelectrics, and frequency control》2005,52(12):2418-2422
A recent study has shown the feasibility of tissue harmonic imaging (THI) using an intravascular ultrasound (IVUS) transducer. This correspondence describes the design, fabrication, and characterization of a THI-optimized piezoelectric transducer with oval aperture of 0.75 mm by 1 mm. The transducer operated at 20 MHz and 40 MHz, and was comprised of a single piezoelectric layer with additional passive layers. The Krimholtz-Leedom-Matthaei (KLM) model was used to iteratively find optimal material properties of the different layers. The transducer characterization showed -6 dB fractional bandwidths of 30% and 25%, and two-way insertion losses of -20 dB and -36 dB, respectively. 相似文献
18.
Qifa Zhou Jonathan M Cannata Hongkai Guo Changzheng Huang Vasilis Z Marmarelis K Kirk Shung 《IEEE transactions on ultrasonics, ferroelectrics, and frequency control》2005,52(1):127-133
Half-thickness inversion layer high-frequency ultrasonic transducers were fabricated using lithium niobate (LiNbO3) single crystal plate. The transducers developed for this study used a 36 degrees rotated Y-cut LiNbO3 thin plate with an active element thickness of 115 microm. The designed center frequency was in the range of 30 to 60 MHz. Half-thickness inversion layer was formed after the sample was annealed at a high temperature, and it is shown that the inversion layer thickness can be controlled by the temperature. Silver powder/epoxy composite and parylene were used as acoustic matching layers. A lossy silver epoxy was used as the backing material. Using an analytical method, the electrical impedance for different inversion layer ratios was determined. The measured resonant frequency was consistent with the modeled data. Even-order higher frequency broadband ultrasonic transducers with a center frequency at 60 MHz was obtained using half-thickness inversion layer of LiNbO3 single crystal. 相似文献
19.
Zhang R Jiang B Jiang W Cao W 《IEEE transactions on ultrasonics, ferroelectrics, and frequency control》2002,49(12):1622-1627
The orientation dependence of slowness and electromechanical coupling coefficients of 0.92Pb(Zn/sub 1/3/Nb/sub 2/3/)O/sub 3/-0.08PbTiO/sub 3/ (PZN-8%PT) domain engineered single crystal was analyzed based on the measured complete set of elastic, piezoelectric, and dielectric constants. There exist one quasi-longitudinal, one quasi-shear, and one pure shear wave in each of the [100]-[010], [010]-[001], and [001]-[110] planes. The slowness of the quasi-shear wave exhibits strong anisotropy in all three planes, and the coupling coefficient k/sub 33/ and k/sub 31/ reach their maximum in [001] and [110] directions of cubic axis, respectively. Because the composition of the PMN-8%PT system is very close to the morphotropic phase boundary, the extraordinary large piezoelectric coefficients d/sub 31/ and d/sub 33/, and high coupling coefficient k/sub 33/ are very sensitive to compositional variation. We have performed error analysis and proposed an improved characterization scheme to derive a complete data set with best consistency. 相似文献