Planar coil excitation of multifrequency shear wave transducers

Stevenson, Alice; Araya-Kleinsteuber, B.; Sethi, R. S.; Metha, H.M.; Lowe, Christopher R.

doi:10.1016/j.bios.2004.04.023

Cited by 20 publications

(15 citation statements)

References 23 publications

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“…The MSCAT sensor's performance was compared to the performance of a standard QCM sensor and an EMPAS with a 16-turn hand wound coil that was fabricated as described in the literature [13,26]. Fifteen solutions of varying viscosities were made by mixing Karo brand corn syrup with deionized water at varying ratios.…”

Section: Methodsmentioning

confidence: 99%

“…are described elsewhere [3][4][5][6]. In contrast to the QCM and LFE sensors which are excited by two electrodes, a hand wound spiral coil has been used as the excitation source in two other acoustic wave sensors, namely the Magnetic Acoustic Resonant Sensor (MARS) [7][8][9][10][11][12] and the Electromagnetic Piezoelectric Acoustic Transduction Sensor (EMPAS) [12][13][14][15][16][17]. The MARS utilizes the same operating principles as Electromagnetic Acoustic Transducers (EMAT), a technology that has been used for more than 50 years on the macro scale [18][19][20] to test the structural integrity of metallic objects such as sheet metal [21] and materials characterization [22].…”

Section: Introductionmentioning

confidence: 99%

“…1b uses only a piezoelectric crystal and a hand wound spiral coil that is separated by a small air gap (~ 30 mm) [12,[13][14][15][16][17]. The hand wound spiral coil produces electric fields that penetrate the piezoelectric material to excite acoustic waves [15].…”

Section: Introductionmentioning

confidence: 99%

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3I-4 A Monolithic Spiral Coil Acoustic Transduction Sensor

Vetelino

McCann

Flewelling

et al. 2006

2006 IEEE Ultrasonics Symposium

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A monolithic spiral coil acoustic transduction (MSCAT) sensor that combines and improves upon the positive features of other acoustic wave sensors has been developed. The MSCAT sensor consists of an AT-cut quartz substrate that has a bare sensing surface and a photolithographically deposited multiturn gold spiral coil on the opposite surface. The spiral coil acts as an antenna that radiates a time varying electric field that penetrates into the AT-quartz wafer. As a result of the piezoelectric effect, the time varying electric field sets up a time varying stress in the wafer. The MSCAT sensor can operate at high frequencies by efficiently exciting high harmonics with the application of a high frequency RF signal to the spiral coil. It is shown that resonant acoustic waves up to the 63 rd order harmonic can be efficiently excited. The MSCAT sensor was used to measure the viscosity of corn syrup. When compared to the performance of the standard quartz crystal monitor (QCM), the MSCAT sensor was found to be over three times more sensitive to viscosity changes. Finally, the MSCAT sensor was shown to be capable of detecting conductivity changes in liquids.

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Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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3I-4 A Monolithic Spiral Coil Acoustic Transduction Sensor

Vetelino

McCann

Flewelling

et al. 2006

2006 IEEE Ultrasonics Symposium

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“…In the MARS device, acoustic generation is achieved in freestanding sensor plates by connecting a planar spiral coil to a radio frequency signal generator, an AM detector and a lock-in amplifier, and positioning it proximal to the lower surface of the plate to produce excitation by converse piezoelectricity (Stevenson et al, 2003b(Stevenson et al, , 2004(Stevenson et al, , 2005. In this way, it is possible to induce remotely and detect acoustic waves in the quartz with electromagnetic and electric fields.…”

Section: Introductionmentioning

confidence: 99%

Magnetic acoustic resonance immunoassay (MARIA): a multifrequency acoustic approach for the non‐labelled detection of biomolecular interactions

Araya-Kleinsteuber

Roque

Kioupritzi

et al. 2006

J of Molecular Recognition

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A unique sensing platform, comprising an electromagnetic field detector and an acoustic resonator, has been used as a wireless system for remote sensing of biorecognition events. The MARS (Magnetic Acoustic Resonator Sensor) technique has proven useful for detecting the formation of protein multilayers derived from specific binding phenomena. The technique enables multifrequency analysis, without the need of electrodes attached to the sensing element, and also facilitates the in situ surface modification of the substrate for antibody attachment. The MARS sensor was utilized as the platform on which a standard immunoassay was carried out. Two different conditions for the attachment of the first antibody to the quartz surface were tested: (i) Adsorption of the antibody onto the surface of a bare quartz disc; (ii) covalent immobilization of the antibody to a chemically modified quartz surface. Both methods can be successfully utilized for the 'label-less' detection of the biorecognition event between goat IgG and anti-goat IgG by analysis of the multifrequency spectrum. Covalent attachment of the primary antibody results in a more efficient immobilization, with higher surface density, and a consistently enhanced response for the binding of the secondary antibody. This approach will be of interest to life scientists and biochemists that require high performance assay methodologies that do not use chemical labels.

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“…Some authors extended the use of the coil design to piezoelectric materials, and applied those non EMAT devices, since no external magnetic field is present, to biosensor investigations [2]. For sensor applications, one aims at tracking a particular resonant peak frequency as a function of variations in the target fluid.…”

Section: Introductionmentioning

confidence: 99%

Improved longitudinal EMAT transducer for elastic constant extraction

Cunha

Jordan

Proceedings of the 2005 IEEE International Frequency Control Symposium and Exposition, 2005.

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Elastic constants are extracted by measuring the shear and longitudinal bulk acoustic wave (BAW) velocities along several crystal orientations. Rapid, precise measurement of crystal elastic properties are fundamental in the evaluation of new materials for the fabrication of acoustic wave based filters and resonators. The extraction of elastic constants can be done by the use of external piezoelectric transducers in pulse echo or sweep frequency time domain reflection techniques. Recently introduced resonant ultrasound techniques can also be used for elastic constants extraction. This paper discusses a novel, highly efficient design for a longitudinal Electromagnetic Acoustic Transducer (L-EMAT) to be used as an alternative in crystal elastic constant extraction. EMATs are used to launch bulk acoustic waves (BAWs) in samples by way of Lorentz's force due to the induction of surface eddy currents in the presence of a static magnetic field. The EMAT technology is a powerful, noncontact technique used for nondestructive evaluation (NDE) of materials. For NDE applications, acoustic wave mode selection is not critical, provided a dominant mode is identified to detect potentially catastrophic microfractures and metal fatigue in structures such as airplane wings and railroad tracks. Recently, this technology has been extended to the extraction of elastic constants of crystals. For precise elastic constant extraction, plate resonators are employed. It is desirable to avoid the excitation of various longitudinal and shear modes by the same EMAT transducer, for two main reasons: (a) the resonating frequency peaks may overlap, reducing the accuracy of the measurement; (b) the efficiency of the transducer in generating the desired mode increases, if only one mode is excited by the EMAT. The longitudinal EMAT design and fabrication originally reported in this paper explores mode selectivity and improved efficiency by: i) increasing the static magnetic field at the surface of the sample;ii) maximizing the current density in the sample's metallic layer; and iii) orienting the current and static magnetic field such that they are orthogonal. The fabricated longitudinal EMAT was used to measure the longitudinal BAW phase velocity values of X-cut and Z-cut quartz samples, and X-cut langatate (LGT, La 3 Ga 5.5 Ta 0.5 O 14 ) samples. Details of the longitudinal EMAT design, its impedance response, the resonant peaks in the frequency spectra of the measured quartz and LGT plate resonators are reported in the paper. The measured results using a RITEC SNAP system showed better than 0.1% accuracy on the quartz and LGT samples when compared to published constants. The designed longitudinal EMAT has shown to be an accurate and simple alternative in determining crystal elastic constants.

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Planar coil excitation of multifrequency shear wave transducers

Cited by 20 publications

References 23 publications

3I-4 A Monolithic Spiral Coil Acoustic Transduction Sensor

3I-4 A Monolithic Spiral Coil Acoustic Transduction Sensor

Magnetic acoustic resonance immunoassay (MARIA): a multifrequency acoustic approach for the non‐labelled detection of biomolecular interactions

Improved longitudinal EMAT transducer for elastic constant extraction

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