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Ultrasonics, Ferroelectrics, and Frequency Control, IEEE Transactions on

Issue 3 • Date March 2013

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Displaying Results 1 - 25 of 28
  • IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control - cover

    Publication Year: 2013 , Page(s): c1 - c2
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  • IEEE Ultrasonics, Ferroelectrics, and Frequency Control Society - Administrative Committee

    Publication Year: 2013 , Page(s): c3
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  • IEEE Ultrasonics, Ferroelectrics, and Frequency Control Society - Elected Administrative Committee

    Publication Year: 2013 , Page(s): c4
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  • Table of contents

    Publication Year: 2013 , Page(s): i - iii
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  • Information for contributors with multimedia addition

    Publication Year: 2013 , Page(s): 437 - 440
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  • Electromechanical properties of relaxor ferroelectric P(VDF-TrFE-CFE)-P(VDF-CTFE) blends

    Publication Year: 2013 , Page(s): 441 - 445
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (533 KB) |  | HTML iconHTML  

    Electromechanical properties of the relaxor ferroelectric poly(vinylidene fluoride-trifluoroethylene-chlorofluoroethylene) [P(VDF-TrFE-CFE)] terpolymer blended with a small amount of poly(vinylidene fluoride-chlorotrifluoroethylene) [P(VDF-CTFE)] copolymer, which possesses a much higher elastic modulus than that of the neat terpolymer, were investigated. It was observed that the presence of small amount of P(VDF-CTFE) does not affect the microstructure of the crystalline phase. However, the uniaxially stretched blended films show a slight increase in the crystallinity and increased or similar induced polarization at high electric fields compared with the neat terpolymer, likely caused by the interface effect. Consequently, for blends with P(VDF-CTFE) less than 5 wt%, the transverse strains S1 along the stretching direction for uniaxially stretched blended films are nearly the same as those of neat P(VDF-TrFE-CFE), whereas the elastic modulus along the S1-direction increases with the P(VDF-CTFE) content. As a result, the blended films exhibit a higher elastic energy density and electromechanical coupling factor k31 compared with the neat terpolymer. View full abstract»

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  • High-temperature actuation performance of BiScO3–PbTiO3 ceramics and their multilayer configuration

    Publication Year: 2013 , Page(s): 446 - 450
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (633 KB) |  | HTML iconHTML  

    Electric-field-induced strains of BiScO3-PbTiO3 (BS-PT) ceramics and actuation performance in multilayer configuration were investigated in the temperature range from 25°C to 250°C. Experimental results confirmed that BS-PT ceramics showed better piezoelectric temperature stability than PZT-5H ceramics, and larger strain than PZT-4 and PZT-8 ceramics at temperatures above 50°C. The strain of a BSPT multilayer actuator prepared by the silicate-cement-glue method was comparable to that of a single-layer BS-PT ceramic. Under ±7.5 kV/cm electric field, the strain of a BS-PT multilayer actuator reached 0.115% at 200°C. Our work shows that BS-PT ceramics are suitable for high-temperature actuation applications. View full abstract»

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  • Performance improvement of fresnel beamforming using dual apodization with cross-correlation

    Publication Year: 2013 , Page(s): 451 - 462
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1594 KB) |  | HTML iconHTML  

    Fresnel beamforming is a beamforming method that has a delay profile with a shape similar to a physical Fresnel lens. With 4 to 8 transmit channels, 2 receive channels, and a network of single-pole/single-throw switches, Fresnel beamforming can reduce the size, cost, and complexity of a beamformer. The performance of Fresnel beamforming is highly dependent on focal errors resulting from phase wraparound and quantization of its delay profile. Previously, we demonstrated that the performance of Fresnel beamforming relative to delay- and- sum (DAS) beamforming is comparable for linear arrays at f-number = 2 and 50% bandwidth. However, focal errors for Fresnel beamforming are larger because of larger path length differences between elements, as in the case of curvilinear arrays compared with linear arrays. In this paper, we present the concept and performance evaluation of Fresnel beamforming combined with a novel clutter suppression method called dual apodization with cross-correlation (DAX) for curvilinear arrays. The contrast-to-noise ratios (CNRs) of Fresnel beamforming followed by DAX are highest at f-number = 3. At f-number = 3, the experimental results show that using DAX, the CNR for Fresnel beamforming improves from 3.7 to 10.6, compared with a CNR of 5.2 for DAS beamforming. Spatial resolution is shown to be unaffected by DAX. At f-number = 3, the lateral beamwidth and axial pulse length for Fresnel beamforming with DAX are 1.44 and 1.00 mm larger than those for DAS beamforming (about 14% and 21% larger), respectively. These experimental results are in good agreement with simulation results. View full abstract»

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  • Pitch-catch phase aberration correction of multiple isoplanatic patches for 3-D transcranial ultrasound imaging

    Publication Year: 2013 , Page(s): 463 - 480
    Cited by:  Papers (1)
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    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (2945 KB) |  | HTML iconHTML  

    Having previously presented the ultrasound brain helmet, a system for simultaneous 3-D ultrasound imaging via both temporal bone acoustic windows, the scanning geometry of this system is utilized to allow each matrix array to serve as a correction source for the opposing array. Aberration is estimated using cross-correlation of RF channel signals, followed by least mean squares solution of the resulting overdetermined system. Delay maps are updated and real-time 3-D scanning resumes. A first attempt is made at using multiple arrival time maps to correct multiple unique aberrators within a single transcranial imaging volume, i.e., several isoplanatic patches. This adaptive imaging technique, which uses steered unfocused waves transmitted by the opposing, or beacon, array, updates the transmit and receive delays of 5 isoplanatic patches within a 64° x 64° volume. In phantom experiments, color flow voxels above a common threshold have also increased by an average of 92%, whereas color flow variance decreased by an average of 10%. This approach has been applied to both temporal acoustic windows of two human subjects, yielding increases in echo brightness in 5 isoplanatic patches with a mean value of 24.3 ± 9.1%, suggesting that such a technique may be beneficial in the future for performing noninvasive 3-D color flow imaging of cerebrovascular disease, including stroke. View full abstract»

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  • Frequency- and phase-sensitive magnetomotive ultrasound imaging of superparamagnetic iron oxide nanoparticles

    Publication Year: 2013 , Page(s): 481 - 491
    Cited by:  Papers (4)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1197 KB) |  | HTML iconHTML  

    It has recently been demonstrated that superparamagnetic iron oxide nanoparticles can be used as magnetomotive ultrasound contrast agents. A time-varying external magnetic field acts to move the particles and, thus, the nanoparticle-laden tissue. However, the difficulty of distinguishing this magnetomotive motion from undesired movement induced in regions without nanoparticles or other motion artifacts has not been well reported. Using a high-frequency linear-array system, we found that displacements outside nanoparticle-laden regions can be similar in magnitude to those in regions containing nanoparticles. We also found that the displacement outside the nanoparticle regions had a phase shift of approximately π radians relative to that in the nanoparticle regions. To suppress signals arising from undesirable movements, we developed an algorithm based on quadrature detection and phase gating at the precise frequency of nanoparticle displacement. Thus, clutter at other frequencies can be filtered out, and the processed signal can be color-coded and superimposed on the B-mode image. The median signal-to-clutter ratio improvement using the proposed algorithm was 36 dB compared with simply summing the movement energy at all frequencies. This clutter rejection is a crucial step to move magnetomotive ultrasound imaging of nanoparticles toward in vivo investigations. View full abstract»

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  • Functional ultrasound imaging of the brain: theory and basic principles

    Publication Year: 2013 , Page(s): 492 - 506
    Cited by:  Papers (5)
    Multimedia
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (2891 KB) |  | HTML iconHTML  

    Hemodynamic changes in the brain are often used as surrogates of neuronal activity to infer the loci of brain activity. A major limitation of conventional Doppler ultrasound for the imaging of these changes is that it is not sensitive enough to detect the blood flow in small vessels where the major part of the hemodynamic response occurs. Here, we present a μDoppler ultrasound method able to detect and map the cerebral blood volume (CBV) over the entire brain with an important increase in sensitivity. This method is based on imaging the brain at an ultrafast frame rate (1 kHz) using compounded plane wave emissions. A theoretical model demonstrates that the gain in sensitivity of the μDoppler method is due to the combination of 1) the high signal-to-noise ratio of the gray scale images, resulting from the synthetic compounding of backscattered echoes; and 2) the extensive signal averaging enabled by the high temporal sampling of ultrafast frame rates. This μDoppler imaging is performed in vivo on trepanned rats without the use of contrast agents. The resulting images reveal detailed maps of the rat brain vascularization with an acquisition time as short as 320 ms per slice. This new method is the basis for a real-time functional ultrasound (fUS) imaging of the brain. View full abstract»

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  • Robotic ultrasound systems in medicine

    Publication Year: 2013 , Page(s): 507 - 523
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    Robots ultrasound (RUS) can be defined as the combination of ultrasound imaging with a robotic system in medical interventions. With their potential for high precision, dexterity, and repeatability, robots are often uniquely suited for ultrasound integration. Although the field is relatively young, it has already generated a multitude of robotic systems for application in dozens of medical procedures. This paper reviews the robotic ultrasound systems that have been developed over the past two decades and describes their potential impact on modern medicine. The RUS projects reviewed include extracorporeal devices, needle guidance systems, and intraoperative systems. View full abstract»

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  • An experimental study on the stiffness of size-isolated microbubbles using atomic force microscopy

    Publication Year: 2013 , Page(s): 524 - 534
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (755 KB) |  | HTML iconHTML  

    To fully assess contrast-enhanced acoustic bioeffects in diagnostic and therapeutic procedures, the mechanical properties of microbubbles need to be considered. In the present study, direct measurements of the microbubble stiffness were performed using atomic force microscopy by applying nanoscale compressions (up to 25 nN/s) on size-isolated, lipidcoated microbubbles (diameter ranges of 4 to 6 μm and 6 to 8 μm). The stiffness was found to lie between 4 and 22 mN/m and to decrease exponentially with the microbubble size within the diameter range investigated. No cantilever spring constant effect was found on the measured stiffness. The Young's modulus of the size-isolated microbubbles used in our study ranged between 0.4 and 2 MPa. Microstructures on the surface of the microbubbles were found to influence the overall microbubble elasticity. Our results indicated that more detailed theoretical models are needed to account for the size-dependent microbubble mechanical properties to accurately predict their acoustic behavior. The findings provided useful insights into guidance of cavitation-induced drug and gene delivery and could be used as part of the framework in studies on the shear stresses induced on the blood vessel walls by oscillating microbubbles. View full abstract»

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  • A beamforming study for implementation of vibro-acoustography with a 1.75-D array transducer

    Publication Year: 2013 , Page(s): 535 - 551
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1669 KB) |  | HTML iconHTML  

    Vibro-acoustography (VA) is an ultrasoundbased imaging modality that uses radiation force produced by two cofocused ultrasound beams separated by a small frequency difference, Δf, to vibrate tissue at Δf. An acoustic field is created by the object vibration and measured with a nearby hydrophone. This method has recently been implemented on a clinical ultrasound system using 1-D linear-array transducers. In this article, we discuss VA beamforming and image formation using a 1.75-D array transducer. A 1.75-D array transducer has several rows of elements in the elevation direction which can be controlled independently for focusing. The advantage of the 1.75-D array over a 1-D linear-array transducer is that multiple rows of elements can be used for improving elevation focus for imaging formation. Six configurations for subaperture design for the two ultrasound beams necessary for VA imaging were analyzed. The point-spread functions for these different configurations were evaluated using a numerical simulation model. Four of these configurations were then chosen for experimental evaluation with a needle hydrophone as well as for scanning two phantoms. Images were formed by scanning a urethane breast phantom and an ex vivo human prostate. VA imaging using a 1.75-D array transducer offers several advantages over scanning with a linear-array transducer, including improved image resolution and contrast resulting from better elevation focusing of the imaging point-spread function. View full abstract»

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  • Design of a phased array for the generation of adaptive radiation force along a path surrounding a breast lesion for dynamic ultrasound elastography imaging

    Publication Year: 2013 , Page(s): 552 - 561
    Cited by:  Papers (1)
    Multimedia
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1510 KB) |  | HTML iconHTML  

    This work demonstrates, with numerical simulations, the potential of an octagonal probe for the generation of radiation forces in a set of points following a path surrounding a breast lesion in the context of dynamic ultrasound elastography imaging. Because of the in-going wave adaptive focusing strategy, the proposed method is adapted to induce shear wave fronts to interact optimally with complex lesions. Transducer elements were based on 1-3 piezocomposite material. Three-dimensional simulations combining the finite element method and boundary element method with periodic boundary conditions in the elevation direction were used to predict acoustic wave radiation in a targeted region of interest. The coupling factor of the piezocomposite material and the radiated power of the transducer were optimized. The transducer's electrical impedance was targeted to 50 Ω. The probe was simulated by assembling the designed transducer elements to build an octagonal phased-array with 256 elements on each edge (for a total of 2048 elements). The central frequency is 4.54 MHz; simulated transducer elements are able to deliver enough power and can generate the radiation force with a relatively low level of voltage excitation. Using dynamic transmitter beamforming techniques, the radiation force along a path and resulting acoustic pattern in the breast were simulated assuming a linear isotropic medium. Magnitude and orientation of the acoustic intensity (radiation force) at any point of a generation path could be controlled for the case of an example representing a heterogeneous medium with an embedded soft mechanical inclusion. View full abstract»

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  • Higher torsional mode suppression in a pipe for enhancing the first torsional mode by using magnetostrictive patch transducers

    Publication Year: 2013 , Page(s): 562 - 572
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1606 KB) |  | HTML iconHTML  

    Small-sized defects in pipes can be better detected if the first nondispersive torsional mode is used in a higher frequency range. However, dispersive higher torsional modes accompany the first mode if the actuation frequency is above the first cutoff frequency, thereby making the detection difficult. This study proposes a new technique that is particularly useful for guided torsional waves in a pipe; it enhances the desired first nondispersive mode and suppresses the undesired second mode. The technique uses two transmitting transducers separated by an optimized distance and actuated with an optimized delay time. Unlike previous methods, such as a method tuning the delay time for desired mode enhancement and tuning the distance for undesired mode suppression, the proposed approach determines both the distance and delay time mainly to suppress the undesired second mode. With the selected values, the desired first mode is substantially enhanced. This phenomenon is unique in torsional waves, not longitudinal waves, for which delay time and distance controlling methods have been developed. After wave simulations were carried out to show why the proposed method is more effective for the case of torsional waves, several experiments using magnetostrictive transducers were performed to demonstrate the effectiveness of the proposed method. View full abstract»

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  • A dual lateral-field-excited bulk acoustic wave sensor array

    Publication Year: 2013 , Page(s): 573 - 578
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (742 KB) |  | HTML iconHTML  

    Recently, there has been interest in the fabrication of multiple quartz crystal microbalances (QCMs) on a single substrate to create a sensor array. However, such devices are ultimately subject to the limitations of the QCM configuration, requiring electrodes and wires on the sensing surface of the crystal substrate, resulting in a cumbersome arrangement that is unable to detect electrical property changes. The lateral-field-excited (LFE) sensor is a novel sensing device that only requires electrodes on the back side of the substrate. With a bare sensing surface, the LFE sensor is a better choice for implementing a sensor array. The purpose of this paper is to report on the fabrication and testing of two independent LFE devices on a single substrate. The individual LFE elements are shown to respond to both electrical and mechanical property changes, with minimal crosstalk between the LFE elements. View full abstract»

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  • Langasite surface acoustic wave gas sensors: modeling and verification

    Publication Year: 2013 , Page(s): 579 - 586
    Cited by:  Papers (1)
    Multimedia
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (964 KB) |  | HTML iconHTML  

    We report finite element simulations of the effect of conductive sensing layers on the surface wave velocity of langasite substrates. The simulations include both the mechanical and electrical influences of the conducting sensing layer. We show that three-dimensional simulations are necessary because of the out-of-plane displacements of the commonly used (0, 138.5, 26.7) Euler angle. Measurements of the transducer input admittance in reflective delay-line devices yield a value for the electromechanical coupling coefficient that is in good agreement with the three-dimensional simulations on bare langasite substrate. The input admittance measurements also show evidence of excitation of an additional wave mode and excess loss resulting from the finger resistance. The results of these simulations and measurements will be useful in the design of surface acoustic wave gas sensors. View full abstract»

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  • A full-duplex ultrasonic through-wall communication and power delivery system

    Publication Year: 2013 , Page(s): 587 - 595
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (909 KB) |  | HTML iconHTML  

    This paper presents a method for two-way ultrasonic communication and power delivery through thick metallic enclosures without physical penetration. Acousticelectric channels are implemented using a pair of coaxially aligned piezoelectric transducers having 25.4 mm diameters and 1 MHz nominal resonant frequencies, mounted on steel walls having lengths in the range of 57.15 to 304.8 mm. A protocol is described which uses ultrasonic waves to achieve simultaneous bidirectional communication through the metallic enclosures. It is shown that such channels are very frequency selective, and a carrier frequency selection and tracking algorithm is presented to choose a frequency of operation at which both adequate power delivery and reliable full-duplex communication are achieved. Using this algorithm, sufficient power is harvested to allow for the continuous operation of internal electronics which require an aggregate of less than 100 mW. Reliable communication of sensor data is achieved at rates in excess of 30 kbps. View full abstract»

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  • Mixed orthogonal frequency coded SAW RFID tags

    Publication Year: 2013 , Page(s): 596 - 602
    Cited by:  Papers (3)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (804 KB) |  | HTML iconHTML  

    Orthogonal frequency coded (OFC) SAW radio-frequency identification (RFID) tags are currently being explored as a multi-sensor platform because of their passive spread-spectrum operation, low loss, and resilience in harsh environments. Ongoing research continues to search for robust device embodiments that increase the number of identifiable codes, in the presence of intersymbol interference, while maintaining reasonable device lengths. This paper presents a technique that shortens the SAW response length while preserving code diversity and bandwidth by utilizing a multi-track SAW configuration. These new devices allow the time response of multiple OFC chips to overlap and yield a mixed-frequency chip having the sum of the chip bandwidths but shorter overall time response. The theoretical development is presented and examples are discussed for these new mixed orthogonal frequency coded (MOFC) SAW devices. Experimental results for MOFC sensors, fabricated on YZ-LiNbO3, with a 7% fractional bandwidth and five chip frequencies in three cells, provide a good contrast to similar OFC designs. Experimental results are presented for the simultaneous operation of eight wireless temperature sensors-four OFC and four MOFC-in a 915-MHz wireless correlator receiver system, highlighting the ability of these devices to operate in the same system. View full abstract»

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  • A new regularization technique for limited-view sound-speed imaging

    Publication Year: 2013 , Page(s): 603 - 613
    Cited by:  Papers (1)
    Multimedia
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1414 KB) |  | HTML iconHTML  

    Reconstructing sound-speed maps from the limited view offered by a linear array of ultrasonic sensors has been a long-standing challenge in medical diagnostics and nondestructive evaluation. Because of the limited range of angles that can be used to interrogate the volume beneath the array, the inverse problem of retrieving sound-speed maps from scattering measurements is highly ill-posed. The missing angles cause significant artifacts that degrade the image by altering the values of sound speed and producing ghost features. This paper introduces the virtual image space component iterative technique (VISCIT), which addresses the limited-view problem by introducing a new regularization technique which iteratively compensates for the missing components by applying an adaptive threshold to the reconstruction. The effectiveness of the method in yielding high-accuracy sound-speed maps is demonstrated using a complex numerical phantom and validated experimentally with an agar phantom. It is shown that sound-speed contrast as low as 1.3% is readily detectable, thus paving the way for more sensitive and selective detection of damage precursors and early stage diseases. View full abstract»

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  • Numerical modeling, calibration, and validation of an ultrasonic separator

    Publication Year: 2013 , Page(s): 614 - 621
    Cited by:  Papers (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1217 KB) |  | HTML iconHTML  

    Our overall goal is to apply acoustic separation technology for the recovery of valuable particulate matter from wastewater in industry. Such large-scale separator systems require detailed design and evaluation to optimize the system performance at the earliest stage possible. Numerical models can facilitate and accelerate the design of this application; therefore, a finite element (FE) model of an ultrasonic particle separator is a prerequisite. In our application, the particle separator consists of a glass resonator chamber with a piezoelectric transducer attached to the glass by means of epoxy adhesive. Separation occurs most efficiently when the system is operated at its main eigenfrequency. The goal of the paper is to calibrate and validate a model of a demonstrator ultrasonic separator, preserving known physical parameters and estimating the remaining unknown or less-certain parameters to allow extrapolation of the model beyond the measured system. A two-step approach was applied to obtain a validated model of the separator. The first step involved the calibration of the piezoelectric transducer. The second step, the subject of this paper, involves the calibration and validation of the entire separator using nonlinear optimization techniques. The results show that the approach lead to a fully calibrated 2-D model of the empty separator, which was validated with experiments on a filled separator chamber. The large sensitivity of the separator to small variations indicated that such a system should either be made and operated within tight specifications to obtain the required performance or the operation of the system should be adaptable to cope with a slightly off-spec system, requiring a feedback controller. View full abstract»

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  • Manipulations of silver nanowires in a droplet on a low-frequency ultrasonic stage

    Publication Year: 2013 , Page(s): 622 - 629
    Cited by:  Papers (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1005 KB) |  | HTML iconHTML  

    In this work, we report the use of a low-frequency circular ultrasonic stage to form a circular spot of silver nanowires (AgNWs) at the stage center and to radially align AgNWs on the stage surface. The manipulations are implemented within an AgNW suspension droplet at the center of the ultrasonic stage. The ultrasonic stage (50.8 mm diameter, 3.5 mm thick) operates at a flexural vibration mode symmetric about its center and has a vibration peak at the center. The AgNW suspension is formed of deionized water with AgNWs dispersed in it. The operating frequency of the ultrasonic stage is 21.3 kHz; the AgNWs have diameter of 100 nm and length of approximately 30 μm. When the ultrasonic stage vibrates properly, AgNWs on the substrate surface in the droplet may move to the stage center and form a spot or rotate to the radial direction and align radially. The spot diameter and thickness are several hundred micrometers and several micrometers, respectively. The rotation speed of a single AgNW can be up to 31°/min when the vibration velocity of the stage center is 42 mm/s (0-p) for a 40-μL droplet. After the droplet dries out by natural evaporation without ultrasound, the spot and radial alignment have little change in the size and pattern. Principle analyses show that the spot formation and radial alignment of AgNWs are caused by the acoustic streaming in the radial direction in the droplet. View full abstract»

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  • Ultra-wideband communication system prototype using orthogonal frequency coded SAW correlators

    Publication Year: 2013 , Page(s): 630 - 636
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1156 KB) |  | HTML iconHTML  

    This paper presents preliminary ultra-wideband (UWB) communication system results utilizing orthogonal frequency coded SAW correlators. Orthogonal frequency coding (OFC) and pseudo-noise (PN) coding provides a means for spread-spectrum UWB. The use of OFC spectrally spreads a PN sequence beyond that of CDMA; allowing for improved correlation gain. The transceiver approach is still very similar to that of the CDMA approach, but provides greater code diversity. Use of SAW correlators eliminates many of the costly components that are typically needed in the intermediate frequency (IF) section in the transmitter and receiver, and greatly reduces the signal processing requirements. Development and results of an experimental prototype system with center frequency of 250 MHz are presented. The prototype system is configured using modular RF components and benchtop pulse generator and frequency source. The SAW correlation filters used in the test setup were designed using 7 chip frequencies within the transducer. The fractional bandwidth of approximately 29% was implemented to exceed the defined UWB specification. Discussion of the filter design and results are presented and are compared with packaged device measurements. A prototype UWB system using OFC SAW correlators is demonstrated in wired and wireless configurations. OFC-coded SAW filters are used for generation of a transmitted spreadspectrum UWB and matched filter correlated reception. Autocorrelation and cross-correlation system outputs are compared. The results demonstrate the feasibility of UWB SAW correlators for use in UWB communication transceivers. View full abstract»

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  • High-performance surface acoustic wave resonators in the 1 to 3 GHz range using a ScAlN/6H-SiC structure

    Publication Year: 2013 , Page(s): 637 - 642
    Cited by:  Papers (5)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (627 KB) |  | HTML iconHTML  

    This paper describes application of Sc-doped AlN (ScAlN) to wideband SAW devices in the 1 to 3 GHz range. First, it is shown theoretically that large SAW velocity and electromechanical coupling factor are simultaneously achievable when the ScAlN film is combined with a base substrate with extremely high acoustic wave velocities, such as diamond and SiC. Next, SAW delay lines are fabricated on the ScAlN/6H-SiC structure, and reasonable agreement between the theory and experiment is obtained. Finally, one-port SAW resonators are fabricated on the structure, and it is shown that high-performance is achievable in the 1 to 3 GHz range by use of the structure. View full abstract»

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Aims & Scope

IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control focuses on the theory, design, and application on generation, transmission, and detection of bulk and surface mechanical waves.

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Meet Our Editors

Editor-in-Chief
Steven Freear
s.freear@leeds.ac.uk