Journal articles: 'MHz acoustic wave'

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Ellis, G. R. A., and P. J. Hall. "A 3072 Channel Surface Acoustic Wave Spectrum Analyser." Publications of the Astronomical Society of Australia 7, no. 1 (1987): 34–35. http://dx.doi.org/10.1017/s1323358000021780.

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AbstractA spectrum analyser based on SAW (surface acoustic wave) devices has been developed for Jupiter, solar and pulsar observations. It has an overall frequency range of 100 MHz and a frequency resolution of 30 kHz. A complete spectrum is produced every 80 μs. It is initially being used with a 4000 dipole broadband array in the frequency range 30-130 MHz and for Jupiter observations from 8-38 MHz.

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Kuznetsova, Iren, Andrey Smirnov, Vladimir Anisimkin, Sergey Gubin, Maria Assunta Signore, Luca Francioso, Jun Kondoh, and Vladimir Kolesov. "Inkjet Printing of Plate Acoustic Wave Devices." Sensors 20, no. 12 (June 12, 2020): 3349. http://dx.doi.org/10.3390/s20123349.

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In the paper, the results of production of Ag inkjet printed interdigital transducers to the acoustic delay line based on Y-cut X-propagation direction of lithium niobate plate for the frequency range from 1 to 14 MHz are presented. Additionally, morphological, structural, and electro-physical characteristics of the obtained electrodes were investigated. Mathematical modeling of the excitation of acoustic waves by these electrode structures was carried out. Comparison of the theoretical results with experimental ones showed their qualitative and quantitative coincidences. It was shown that conventional inkjet printing can replace the complex photolithographic method for production of interdigital transducers for acoustic delay lines working up to 14 MHz. The resulting electrode structures make it possible to efficiently excite acoustic waves with a high value of electromechanical coupling coefficient in piezoelectric plates.

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SEEMANN, K. M., F. KRONAST, A. HÖRNER, S. VALENCIA, A. WIXFORTH, A. V. CHAPLIK, and P. FISCHER. "ATTENUATION OF SURFACE ACOUSTIC WAVES BY SPIN–WAVE EXCITATIONS IN Co60Fe20B20." SPIN 04, no. 01 (March 2014): 1440005. http://dx.doi.org/10.1142/s2010324714400050.

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The acousto-magnetic attenuation of surface acoustic waves (SAW) in an Co 60 Fe 20 B 20 exchange spring magnet is evidenced experimentally. By high-resolution magnetic imaging using photo-excitation electron microscopy (XPEEM) and magnetometry measurements, the deflection of the ferromagnet from its equilibrium state is visualized. Along a harmonic oscillator model with damping term, the experimental observation of SAW attenuation is attributed to low-frequency spin wave generation in a magnetic exchange spring. Measuring the SAW attenuation at four eigenfrequencies generated via on-chip higher-harmonic generation, we obtain a sub-GHz resonance at f0 = 538 MHz.

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Yu, Tai-Ho. "Characteristic measurement of a surface acoustic wave nano-stepping motor by using a fiber-optic Michelson interferometer." Advances in Mechanical Engineering 11, no. 9 (September 2019): 168781401987619. http://dx.doi.org/10.1177/1687814019876190.

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The actuation technique of a surface acoustic wave motor with nanometer scale linear motion was experimentally investigated in this study. The surface acoustic wave motor comprised a stator made of a Y+128° cut, X-propagation lithium niobate substrate with silicon sliders and an array of pillar projections manufactured using semiconductor fabrication techniques. Two sets of interdigital transducers deposited on the substrate were used to generate Rayleigh waves with a driving frequency of up to 9.7 MHz. The surface acoustic wave motor was driven by friction exerted on the contact area between the slider and the surface acoustic waves in a retrogressive elliptical locus. The stepping motion of the surface acoustic wave motor was measured directly using a fiber-optic Michelson interferometer through demodulation with a digital signal processing method. A displacement of several nanometers was achieved at each step during the experiment.

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Javadi, Yashar, and Sergej Hloch. "Employing the Waves to Measure Longitudinal Residual Stresses in Different Depths of a Stainless Steel Welded Plate." Advances in Materials Science and Engineering 2013 (2013): 1–8. http://dx.doi.org/10.1155/2013/746187.

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Ultrasonic stress measurement is based on the acoustoelasticity law which presents the relationship between the stress and acoustic wave velocity in engineering materials. The technique uses longitudinal critically refracted () waves that travel parallel to the material surface. The wave is a bulk longitudinal wave that propagates within an effective depth underneath the surface while the penetration depth of a wave depends on its frequency. It is possible to measure the residual stress in different depths by employing different frequencies of the waves. This paper evaluates welding residual stresses in different depths of a plate made of austenitic stainless steel (304L). The penetration depths are accurately measured for the waves produced by 1 MHz, 2 MHz, 4 MHz, and 5 MHz transducers. Residual stresses through the thickness of the plate are then evaluated by employing four different series of transducers. It has been concluded that the method is nondestructive, easy and fast, portable, readily available, and low cost and bulk measuring technique which can be accurately employed in through-thickness stress measurement of austenitic stainless steels.

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Sharma, Parmanand, Sanjeev Kumar, and K. Sreenivas. "Interaction of surface acoustic waves and ultraviolet light in ZnO films." Journal of Materials Research 18, no. 3 (March 2003): 545–48. http://dx.doi.org/10.1557/jmr.2003.0069.

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The frequency response of a 37 MHz bulk LiNbO3 surface acoustic wave (SAW) filter with a 200-nm-thick ZnO overlayer exhibited a downshift in the frequency with ultraviolet (UV) light due to acoustoelectric interactions between the photo-generated carriers in the semiconducting ZnO and the surface acoustic waves. In contrast, a 36 MHz ZnO thin film SAW delay-line with insulating ZnO films exhibited an upshift in the frequency. The response was more pronounced at higher harmonics (130–315 MHz) and was attributed to changes in the elastic/dielectric properties in the upper surface layer of ZnO. A linear change in the frequency with UV intensity shows immense applicability for wireless ultraviolet sensor applications.

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Raboonik, Abbas, and Paul S. Cally. "Benchmarking hall-induced magnetoacoustic to Alfvén mode conversion in the solar chromosphere." Monthly Notices of the Royal Astronomical Society 507, no. 2 (August 13, 2021): 2671–83. http://dx.doi.org/10.1093/mnras/stab2293.

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ABSTRACT A 2.5D numerical model of magnetoacoustic-Alfvén linear mode conversions in the partially ionized low solar atmosphere induced by the Hall effect is surveyed, varying magnetic field strength and inclination, and wave frequency and horizontal wavenumber. It is found that only the magnetic component of wave energy is subject to Hall-mediated conversions to Alfvén wave-energy via a process of polarization rotation. This strongly boosts direct mode conversion between slow magnetoacoustic and Alfvén waves in the quiet low chromosphere, even at mHz frequencies. However, fast waves there, which are predominantly acoustic in nature, are only subject to Hall-induced conversion via an indirect two-step process: (i) a geometry-induced fast–slow transformation near the Alfvén-acoustic equipartition height zeq; and (ii) Hall-rotation of the fast wave in z > zeq. Thus, for the two-stage process to yield upgoing Alfvén waves, zeq must lie below or within the Hall-effective window 0 ≲ z ≲ 700 km. Magnetic field strengths over 100 G are required to achieve this. Since the potency of this Hall effect varies inversely with the field strength but directly with the wave frequency, only frequencies above about 100 mHz are significantly affected by the two-stage process. Increasing magnetic field inclination θ generally strengthens the Hall convertibility, but the horizontal wavenumber kx has little effect. The direct and indirect Hall mechanisms both have implications for the ability of MHD waves excited at the photosphere to reach the upper chromosphere, and by implication the corona.

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Chukwunonye, C. U., Nicholas J. Jones, and Gabriela Petculescu. "Sensitization in Aluminum Alloys: Effect on Acoustic Parameters." Corrosion 74, no. 11 (August 15, 2018): 1237–44. http://dx.doi.org/10.5006/2832.

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Velocity and attenuation of shear and longitudinal sound waves were measured as a function of sensitization level in AA5083-H116 and AA5456-H116 aluminum alloys using two different techniques: resonant ultrasound spectroscopy (RUS) and pulse echo (PE). The frequency range for RUS was 0.3 MHz to 1 MHz. For PE, longitudinal 3.5 MHz and shear 1 MHz transducers were used. Sensitization was artificially induced in the laboratory by isothermally heating specimens at temperatures of 120°C, 175°C, 185°C, and 240°C for fixed periods of time (12 h to 96 h, the longer times for the lower temperatures). Measurements were repeated after each heating sequence. The overall changes are reported as percent difference between the as received and the fully sensitized states. The quantity that was found to be most sensitive to the degree of sensitization in this study is the attenuation coefficient of longitudinal waves, αL. The measured change in αL exceeds 20%, with error bars within 1% to 4%. Despite the magnitude of the error bars, the αL vs. degree-of-sensitization curve is clear and smooth. The shear wave velocity changed by 1.2% to 1.5%, with error bars within 0.01% to 0.1%. The larger change was observed for the AA5456 alloy, which contains more Mg. The longitudinal wave velocity was found to change by 0.5% for the 5456 alloy, with error bars within 0.004% to 0.02%. The attenuation coefficient for shear waves was not measured. This study identifies multiple ultrasonic parameters that can be combined into a new, on-site, nondestructive tool for quantitatively monitoring the sensitization level in Mg-rich aluminum alloys, with possible extensions to other materials.

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Jarosz, B. J., and R. L. Clarke. "Acoustic radiation from thin rods in water." Canadian Journal of Physics 64, no. 6 (June 1, 1986): 671–76. http://dx.doi.org/10.1139/p86-124.

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The ultrasound pressure distribution produced by end-excited stainless-steel rods immersed in water has been investigated. Rod diameters of 0.238 and 0.319 cm were tested at frequencies between 1.0 and 3.5 MHz. Immersion depths up to 10 cm were studied. Semiperiodic patterns were observed along the rods, with repetition lengths of 0.6 and 1.1 cm. Fast Fourier-transform analysis of the patterns showed the presence of three spatial frequencies interpreted to be the lowest mode longitudinal wave, Rayleigh-type surface waves, and the Stoneley wave propagating in the liquid.

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Zhang, Naiqing, Yue Wen, and James Friend. "MHz-Order Surface Acoustic Wave Thruster for Underwater Silent Propulsion." Micromachines 11, no. 4 (April 16, 2020): 419. http://dx.doi.org/10.3390/mi11040419.

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High frequency (MHz-order) surface acoustic waves (SAW) are able to generate intense fluid flow from the attenuation of acoustic radiation in viscous fluids as acoustic streaming. Though such flows are known to produce a force upon the fluid and an equivalent and opposing force upon the object producing the acoustic radiation, there is no convenient method for measuring this force. We describe a new method to accomplish this aim, noting the potential of these devices in providing essentially silent underwater propulsion by virtue of their use of the sound itself to generate fluid momentum flux. Our example employs a 40 MHz SAW device as a pendulum bob while immersed in a fluid, measuring a 1.5 mN propulsion force from an input power of 5 W power to the SAW device. Supporting details regarding the acoustic streaming profile via particle image velocimetry and an associated theoretical model are provided to aid in the determination of the propulsion force knowing the applied power and fluid characteristics. Finally, a simple model is provided to aid the selection of the acoustic device size to maximize the propulsion force per unit device area, a key figure of merit in underwater propulsion devices. Using this model, a maximum force of approximately 10 mN/cm 2 was obtained from 1 W input power using 40 MHz SAW in water and producing a power efficiency of approximately 50%. Given the advantages of this technology in silent propulsion with such large efficiency and propulsion force per unit volume, it seems likely this method will be beneficial in propelling small autonomous submersibles.

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Bowers, W. D., R. L. Chuan, and T. M. Duong. "A 200 MHz surface acoustic wave resonator mass microbalance." Review of Scientific Instruments 62, no. 6 (June 1991): 1624–29. http://dx.doi.org/10.1063/1.1142442.

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Zhou, Jian, Xingli He, Wenbo Wang, Nana Hu, Hao Jin, Y. Xu, Shurong Dong, Demiao Wang, Y. Q. Fu, and J. K. Luo. "Flexible surface acoustic wave devices and its applications in microfluidics." MRS Proceedings 1659 (2014): 27–33. http://dx.doi.org/10.1557/opl.2014.33.

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Abstract:Flexible electronics and microsystems are an emerging technology with a tremedous impact to the future electronics and information technology and widespread applications. Various devices and microsystems have been developed. Surface acoustic wave (SAW) devices are a type of essential device for electronics, microsensors and microsystems; however there is no activity on the development of flexible SAW devices yet. This paper reports the development of flexible SAW devices on cheap, bendable and disposable plastic films. Flexible SAW devices with resonant frequency of 198.1 MHz and 447 MHz for the Rayleigh and Lamb waves respectively have been obtained with a large transmission signal up to 18dB. The flexible SAW devices have also demonstrated their ability for acoustic streaming with a velocity up to 3.4 cm/s and for particle concentration. The results have clearly demonstrated that the flexible SAW devices have great potential for applications in electronics and microsystems.

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Awal, Md Rabiul, Muzammil Jusoh, Muhammad Syarifuddin Yahya, Salisa Abdul Rahman, Ahmad Nazri Dagang, Nurul Adilah Abdul Latiff, Hidayatul Aini Zakaria, and Shakir Saat. "ACOUSTIC WAVE PROPAGATION IN HIGH SCALE IMPEDANCE MISMATCH MEDIUMS." IIUM Engineering Journal 22, no. 2 (July 4, 2021): 1–9. http://dx.doi.org/10.31436/iiumej.v22i2.1563.

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A finite element analysis of acoustic propagation in a multilayered medium is presented in this paper. A circular transmitter (diameter 14 mm, thickness 3 mm) and a rectangular receiver (20×10×0.5 mm3) are set to detect the variations in the propagation pattern. A complex medium (70×40×60 mm3) composed of skin, fat, muscle, bone and liquid is designed in a simulated environment. A scale of frequencies (10 kHz to 2 MHz) is applied to trace the impact on the propagation pattern as well. It is found from the analysis that fat and liquid layers affect the acoustic propagation the most (-69 dB), which results in a significant drop in the received sound pressure level at the receiving end. Again, other than skin and fat layers, low frequencies (less than 1 MHz) are more beneficial in terms of sound pressure level. However, higher frequencies contribute to lower displacements at the receiving end, which will cause less power potential as well. ABSTRAK: Analisis elemen terhingga bagi penyebaran akustik dalam medium berlapis dibentangkan dalam kajian ini. Pemancar bulat (diameter 14 mm, ketebalan 3 mm) dan penerima segi empat tepat (20 × 10 × 0.5 mm3) diatur bagi mengesan perubahan pola penyebaran. Medium kompleks (70 × 40 × 60 mm3) yang terdiri daripada kulit, lemak, otot, tulang dan cecair direka dalam persekitaran simulasi. Skala frekuensi (10 kHz hingga 2 MHz) digunakan bagi mengesan corak penyebaran. Dapatan kajian menunjukkan bahawa lapisan lemak dan cecair mempengaruhi penyebaran akustik (-69 dB), yang mengakibatkan penurunan mendadak tahap penerimaan tekanan bunyi di hujung penerima. Selain lapisan kulit dan lemak, frekuensi rendah (kurang dari 1 MHz) adalah lebih berguna dari segi tahap tekanan suara. Walau bagaimanapun, frekuensi lebih tinggi menyebabkan kurang anjakan di hujung penerima, sekaligus mengurangkan potensi daya tenaga.

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Gao, Junning, Zhibiao Hao, Lang Niu, Lai Wang, Changzheng Sun, Bin Xiong, Yanjun Han, et al. "Surface acoustic wave devices fabricated on epitaxial AlN film." Functional Materials Letters 09, no. 02 (April 2016): 1650034. http://dx.doi.org/10.1142/s179360471650034x.

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This paper reports surface acoustic wave (SAW) devices fabricated on AlN epitaxial film grown on sapphire, aiming to avoid the detrimental polarization axis inconsistency and refrained crystalline quality of the normally used polycrystalline AlN films. Devices with center frequency of 357 MHz and 714 MHz have been fabricated. The stop band rejection ratio of the as-obtained device reaches 24.5 dB and the pass band ripple is profoundly smaller compared to most of the reported AlN SAW devices with the similar configuration. Judging from the rather high edge dislocation level of the film used in this study, the properties of the SAW devices have great potential to be improved by further improving the crystalline quality of the film. It is then concluded that the AlN epitaxial film is favorable for high quality SAW devices to meet the high frequency and low power consumption challenges facing the signal processing components.

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Kazys, Rymantas, Algirdas Voleisis, and Reimondas Sliteris. "Investigation of the Acoustic Properties of Viscosity Standards." Archives of Acoustics 41, no. 1 (March 1, 2016): 55–58. http://dx.doi.org/10.1515/aoa-2016-0005.

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Abstract Longitudinal and shear ultrasonic wave velocities were measured versus temperature in the viscosity standards of Paragon S8000S, N30000S and Cannon N2700000. The measurements were performed by the through-transmission method at the frequency of 2 MHz. Ultrasonic pulses were sent via polymethyl methacrylate (PMMA) waveguides between the tips of which a small amount of the particular standard liquid was placed. The velocities of longitudinal and shear waves were determined to depend on the viscosity of the liquid and increase with the viscosity.

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Zhang, Naiqing, Yue Wen, and James Friend. "MHz-order surface acoustic wave thruster for underwater silent propulsion." Journal of the Acoustical Society of America 146, no. 4 (October 2019): 2866. http://dx.doi.org/10.1121/1.5136944.

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Maruyama, Takashi, Kamil Yusupov, and Adel Akchurin. "Interpretation of deformed ionograms induced by vertical ground motion of seismic Rayleigh waves and infrasound in the thermosphere." Annales Geophysicae 34, no. 2 (February 18, 2016): 271–78. http://dx.doi.org/10.5194/angeo-34-271-2016.

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Abstract. The vertical ground motion of seismic surface waves launches acoustic waves into the atmosphere and induces ionospheric disturbances. Disturbances due to Rayleigh waves near the short-period Airy phase appear as wavy fluctuations in the virtual height of an ionogram and have a multiple-cusp signature (MCS) when the fluctuation amplitude is increased. An extremely developed MCS was observed at Kazan, Russia, after the 2010 M 8.8 Chile earthquake. The ionogram exhibited steep satellite traces for which the virtual heights increased rapidly with frequency starting near the top of cusps and continuing for 0.1–0.2 MHz. This complicated ionogram was analyzed by applying a ray tracing technique to the radio wave propagation in the ionosphere that was perturbed by acoustic waves. Acoustic wavefronts were inclined by the effects of finite Rayleigh wave velocity and sound speed in the thermosphere. The satellite echo traces were reproduced by oblique returns from the inclined wavefronts, in addition to the nearly vertical returns that are responsible for the main trace.

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Narayan, Advaith, Mingyang Cui, and J. Mark Meacham. "Using motile cells to characterize surface acoustic wave-based acoustofluidic devices." Journal of the Acoustical Society of America 152, no. 4 (October 2022): A35. http://dx.doi.org/10.1121/10.0015453.

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Acoustic microfluidics is a robust and powerful method to manipulate cells and cell-like particles on chip, having good biocompatibility and ease of incorporation into multioperation microfluidic devices compared to optical manipulation. However, the use of acoustic microfluidics is largely confined to research settings. The primary barrier to translation of this technology toward clinical and industrial uses is the inability to experimentally determine the pressure field (shape and amplitude) and associated acoustophoretic forces in real time as device conditions vary. Despite the multitude of previous characterization methods, none provide the flexibility of motile cells (e.g., the unicellular alga Chlamydomonas reinhardtii) as probes to map evolving pressure fields on chip. We have previously developed this approach for use with bulk acoustic wave (BAW)-based devices. Here, we extend the method to qualitatively assess device resonances and relative field strengths for surface acoustic wave (SAW)-based devices with straight channels and circular chambers driven at 6 MHz and 20 MHz. The fabrication and electrical characterization of hybrid BAW/SAW devices with glass channels are also discussed. Upon testing, the optimal device operating parameters are identified using impedance measurements, as well as visual identification of resonant frequencies using the swimming algae cells.

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Aprillo, Laksamana Agung, Hendy Santosa, and Faisal Hadi. "Analisis Total Electron Content (TEC) Menggunakan Continous Wavelet Transform Sebagai Indikator Prekursor Gempa Bumi Di Wilayah Provinsi Bengkulu." JURNAL AMPLIFIER : JURNAL ILMIAH BIDANG TEKNIK ELEKTRO DAN KOMPUTER 9, no. 2 (November 30, 2019): 27–33. http://dx.doi.org/10.33369/jamplifier.v9i2.15380.

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ABSTRACT Bengkulu is one of 34 provinces in Indonesia which is a megathrust region. So Bengkulu province is often hit by many large earthquakes with shallow depth. TEC anomaly was analyzed based on three electromagnetic waves radiated by an earthquake. The total electron content (TEC) anomaly is seen through the global positioning system (GPS) dual-frequency radio signal data. The continuous wavelet transform (CWT) method is used to divide the signal analysis into several sections according to the electromagnetic wave frequency range of acoustic (2.5 mHz) -3 mHz), gravity waves (1 mHz-2.8 mHz) and rayleigh waves (5 mHz-33 mHz). GPS observation data for 9 days is calculated using the Standard deviation (2?) method to see trends in data changes. The analysis shows anomalies in the September 12 2007 earthquake (7.9 Mw), the March 5 2010 earthquake (6.3 Mw) and the August 4 2011 earthquake (6.0 Mw). Anomalies are detected 1 to 5 hours before an earthquake occurs. TEC anomalies that occur may be related to the process of preseismic before the earthquake and may be an early sign of an earthquake.Keyword: earthquake, total electron content, continous wavelet transform, standard deviation

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Long, Yin, Xiaosong Du, Yang Wang, Jinzhu Zhao, Huiling Tai, Xianzhong Tang, and Yadong Jiang. "Hydrogen-bond acidic polymers coated SAW sensors for 2,4-dinitrotoluene detection." RSC Adv. 4, no. 103 (2014): 59643–49. http://dx.doi.org/10.1039/c4ra11525b.

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Kotov, V. M., and S. V. Averin. "Acoustooptic Diffraction of Three-Color Radiation on a Single Acoustic Wave." International Journal of Optics 2019 (February 24, 2019): 1–5. http://dx.doi.org/10.1155/2019/4386093.

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Bragg diffraction which provides effective acoustooptic interaction of three-color radiation with a single acoustic wave at a high frequency of sound is proposed and tested in a single crystal of paratellurite at the wavelengths of λ= 0.488, 0.514, and 0.633 μm. Maximal diffraction efficiency of radiation with λ=0.633 μm at acoustic frequency of 150 MHz is 88% and that with λ= 0.488 μm and λ=0.514 μm is 60%. In diffraction efficiency range from 0 to 40% the dependence of all beams on acoustic power is the same.

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Ktari, N., N. Fourati, C. Zerrouki, M. Ruan, M. Seydou, F. Barbaut, F. Nal, N. Yaakoubi, M. M. Chehimi, and R. Kalfat. "Design of a polypyrrole MIP-SAW sensor for selective detection of flumequine in aqueous media. Correlation between experimental results and DFT calculations." RSC Advances 5, no. 108 (2015): 88666–74. http://dx.doi.org/10.1039/c5ra16237h.

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A shear horizontal surface acoustic wave sensor (SH-SAW) operating at 104 MHz was functionalized with a polypyrrole (PPy) molecularly imprinted polymer (MIP) for selective detection of flumequine (FLU) in aqueous media.

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Liu, Jiacheng, Temesgen Bailie Workie, Ting Wu, Zhaohui Wu, Keyuan Gong, Jingfu Bao, and Ken-ya Hashimoto. "Q-Factor Enhancement of Thin-Film Piezoelectric-on-Silicon MEMS Resonator by Phononic Crystal-Reflector Composite Structure." Micromachines 11, no. 12 (December 20, 2020): 1130. http://dx.doi.org/10.3390/mi11121130.

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Thin-film piezoelectric-on-silicon (TPoS) microelectromechanical (MEMS) resonators are required to have high Q-factor to offer satisfactory results in their application areas, such as oscillator, filter, and sensors. This paper proposed a phononic crystal (PnC)-reflector composite structure to improve the Q factor of TPoS resonators. A one-dimensional phononic crystal is designed and deployed on the tether aiming to suppress the acoustic leakage loss as the acoustic wave with frequency in the range of the PnC is not able to propagate through it, and a reflector is fixed on the anchoring boundaries to reflect the acoustic wave that lefts from the effect of the PnC. Several 10 MHz TPoS resonators are fabricated and tested from which the Q-factor of the proposed 10 MHz TPoS resonator which has PnC-reflector composite structure on the tether and anchoring boundaries achieved offers a loaded Q-factor of 4682 which is about a threefold improvement compared to that of the conventional resonator which is about 1570.

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Campbell, William, Serge Galliou, Michael E. Tobar, and Maxim Goryachev. "Electro-mechanical tuning of high-Q bulk acoustic phonon modes at cryogenic temperatures." Applied Physics Letters 122, no. 3 (January 16, 2023): 032202. http://dx.doi.org/10.1063/5.0131361.

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We investigate the electromechanical properties of quartz bulk acoustic wave resonators at extreme cryogenic temperatures. By applying a DC bias voltage, we demonstrate broad frequency tuning of high-Q phonon modes in a quartz bulk acoustic wave cavity at cryogenic temperatures of 4 K and 20 mK. More than 100 line-widths of tuning of the resonance peak without any degradation in loaded quality factor, which are as high as [Formula: see text], is seen for high order overtone modes. For all modes and temperatures, the observed coefficient of frequency tuning is [Formula: see text] 3.5 mHz/V per overtone number n corresponding to a maximum of 255.5 mHz/V for the n = 73 overtone mode. No degradation in the quality factor is observed for any value of an applied biasing field.

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Chowdhury, Md Fahim F., Walid Al Misba, Md Mahadi Rajib, Alexander J. Edwards, Dhritiman Bhattacharya, Mathew S. Varghese, Joseph S. Friedman, and Jayasimha Atulasimha. "Focused surface acoustic wave induced nano-oscillator based reservoir computing." Applied Physics Letters 121, no. 10 (September 5, 2022): 102402. http://dx.doi.org/10.1063/5.0110769.

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We demonstrate using micromagnetic simulations that a nanomagnet array excited by surface acoustic waves (SAWs) can work as a reservoir. An input nanomagnet is excited with focused SAW and coupled to several nanomagnets, seven of which serve as output nanomagnets. To evaluate memory effect and computing capability, we study the short-term memory (STM) and parity check (PC) capacities, respectively. The SAW (4 GHz carrier frequency) amplitude is modulated to provide a sequence of sine and square waves of 100 MHz frequency. The responses of the selected output nanomagnets are processed by reading the envelope of their magnetization states, which is used to train the output weights using the regression method. For classification, a random sequence of 100 square and sine wave samples is used, of which 80% are used for training, and the rest are used for testing. We achieve 100% training and 100% testing accuracy. The average STM and PC are calculated to be ∼4.69 and ∼5.39 bits, respectively, which is indicative of the proposed acoustically driven nanomagnet oscillator array being well suited for physical reservoir computing applications. The energy dissipation is ∼2.5 times lower than a CMOS-based echo-state network. Furthermore, the reservoir is able to accurately predict Mackey-Glass time series up to several time steps ahead. Finally, the ability to use high frequency SAW makes the nanomagnet reservoir scalable to small dimensions, and the ability to modulate the envelope at a lower frequency (100 MHz) adds flexibility to encode different signals beyond the sine/square waves classification and Mackey-Glass predication tasks demonstrated here.

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KURUOĞLU, Furkan. "Influence of the Core Pillar Height on the Bandgap Characteristics of Piezoelectric Phononic Crystals with Ring-Shaped Grooves." Cumhuriyet Science Journal 43, no. 2 (June 29, 2022): 346–50. http://dx.doi.org/10.17776/csj.1104315.

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Dispersion profiles and surface acoustic wave attenuation characteristics of ring-shaped phononic crystals are investigated as a function of the core pillar height. Finite element method simulations are carried out for both band analyses and transmission spectra calculations. The results reveal that increasing core pillar height results in a decrement in the local resonance band frequency and the corresponding transmission peaks. The obtained dispersion profiles show that the phononic crystal bandgap also expands from 6 MHz to 11 MHz while the pillar height increases from 5 um to 7 um. Similar characteristics are also seen in the transmission spectra for the varying core pillar heights of the ring-shaped periodic grooves. In addition, surface acoustic wave attenuation competency depends on the core pillar height. The frequencies where the investigated phononic crystals are functional can be tuned by adjusting the core pillar height.

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Ilyahinsky, A. V., and V. M. Rodyushkin. "About the nonlinear acoustic parameter during deformation of AMG61 alloy." PNRPU Mechanics Bulletin, no. 3 (December 15, 2020): 41–47. http://dx.doi.org/10.15593/perm.mech/2020.3.05.

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Various acoustic effects are used in the study of deformation processes. Acoustic emission is most often mentioned in such studies, and the effects due to nonlinear properties of a deformable metal are the subject of the present work. These properties of real solids lead to nonlinear acoustic effects of the interaction elastic waves forbidden by the theory of elasticity of a homogeneous isotropic body. The work solves the problem of using the principles of nonlinear acoustics in studying the deformation of AMg61 alloy samples. A surface elastic wave is used to control the alloy condition. The process of the elastic wave propagation in the deformed AMg61 alloy due to nonlinear effects is accompanied by generating the double frequency, both of the longitudinal component of the wave and the shear one, the latter is forbidden by equations of the classical elasticity theory. Excitation and reception in the samples was carried out by piezoelectric converters (PES). A wedge converter with a resonance frequency of 1MHz was used to excite the surfactant. The passing surfactant was recorded by a wedge converter with a resonance frequency of 2 MHz. We justified the control technique of the nonlinear acoustic parameter with respect to amplitudes of the first and second harmonics measured during the whole deformation process. An experimental device has been developed to control the nonlinear acoustic parameter in the process of changing the structural state of the sample metal. The pilot study results of the nonlinear acoustic parameter under Amg61 alloy deformation are given. It is shown that the nonlinear acoustic parameter, as well as the acoustic emission activity, is sensitive to changing mechanisms of the defective structure evolution. The non-linearity jump formation during deformation of alloy AMg61 is recorded, which may indicate adjustment of the metal structure. The presented data demonstrate the increase of acoustic nonlinearity in metal at various deformation stages, both at early stages of elastoplastic deformation and at pre-destruction stage, which can be used as the prognostic criterion.

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Morgan, David P. "A HISTORY OF SURFACE ACOUSTIC WAVE DEVICES." International Journal of High Speed Electronics and Systems 10, no. 03 (September 2000): 553–602. http://dx.doi.org/10.1142/s0129156400000593.

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This paper gives a historical account of the development of Rayleigh-wave, or surface-acoustic-wave (SAW), devices for applications in electronics. The subject was spurred on initially by the requirements of pulse compression radar, and became a practical reality with the planar interdigital transducer, dating from 1965. The accessibility of the propagation path gave rise to substantial versatility, and a huge variety of devices were developed. Passive SAW devices are now ubiquitous, with applications ranging from professional radar and communications systems to consumer areas such as TV, pagers and mobile phones. The paper describes the extensive work, particularly in the 1970s, to investigate SAW propagation in crystalline media, including piezoelectric coupling, diffraction and temperature effects. This led to identification of many suitable materials. Concurrently, many devices began development, including pulse compression filters, bandpass filters, resonators, oscillators, convolvers and matched filters for spread spectrum communications. In the 1970s, many of these became established in professional systems, and the SAW bandpass filter became a standard component for domestic TV. In the 1980s and 90s, SAW responded to the new call for low-loss filters, particularly for mobile phones. With losses as low as 2 dB required (and subsequently achieved) at RF frequencies around 900 MHz, a raft of new technologies was developed. Additionaly, for IF filters special techniques were evolved to reduce the physical size needed for narrow bandwidths. Such devices are now manufactured in very large quantities. In order to satisfy these needs, new types of surface wave, particularly transverse leaky waves, were investigated, and materials using such waves now have their place alongside more traditional materials.

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Alhazmi, Hani, and Rasim Guldiken. "Contactless Liquid Height and Property Estimation Using Surface Acoustic Waves." Acoustics 2, no. 2 (June 6, 2020): 366–81. http://dx.doi.org/10.3390/acoustics2020021.

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The propagation of surface acoustic waves over a solid plate is highly influenced by the presence of liquid media on the surface. At the solid–liquid interface, a leaky Rayleigh wave radiates energy into the liquid, causing a signification attenuation of the surface acoustic wave amplitude. In this study, we take advantage of this spurious wave mode to predict the characteristics of the media, including the volume or height. In this study, the surface acoustic waves were generated on a thick 1018 steel surface via a 5 MHz transducer coupled through an angle beam wedge. A 3D-printed container was inserted on the propagation path. The pulse-echo time-domain responses of the signal were recorded at five different volumes (0, 400, 600, 1000, and 1800 µL). With the aid of parametric CAD analysis, both the position and distance of the entire traveling wave in the liquid layer were modeled and verified with experimental studies. The results indicated that the average drop in the reflected wave amplitude due to liquid loading is −62.5% compared to the empty container, with a percentage of error within 10% for all cases. The localized-time frequency components of the reflected wave were obtained via a Short-Time Fourier Transform technique. Up to 10% reduction (500 KHz) in the central frequency was observed due to the liquid volume increasing. The method discussed herein could be useful for many applications, where some of the liquid’s parameters or the ultrasonic wave behavior in the liquid need to be assessed.

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Bruus, Henrik. "Ultrasound rays in droplets: the role of viscosity and caustics in acoustic streaming." Journal of Fluid Mechanics 826 (August 2, 2017): 1–4. http://dx.doi.org/10.1017/jfm.2017.420.

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When an acoustic wave propagates through a viscous fluid, it progressively transfers momentum to the fluid through viscous dissipation, which results in the formation of a steady vortical flow called acoustic streaming. Although spawned by viscous effects, the magnitude of the streaming does not depend on the viscosity in most simple geometries. However, viscosity has a profound influence on the acoustic streaming as demonstrated by Riaud et al. (J. Fluid Mech., vol. 821, 2017, pp. 384–420) in their study of sessile mm-sized water–glycerol droplets placed on a piezoelectric substrate with a 20-MHz ultrasound surface acoustic wave propagating along its surface. A detailed experimental and numerical analysis reveals that streaming dynamics is driven by a few ultrasound ray caustics inside the droplet.

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Anisimkin, Vladimir, Vladimir Kolesov, Anastasia Kuznetsova, Elizaveta Shamsutdinova, and Iren Kuznetsova. "An Analysis of the Water-to-Ice Phase Transition Using Acoustic Plate Waves." Sensors 21, no. 3 (January 29, 2021): 919. http://dx.doi.org/10.3390/s21030919.

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It is shown that, in spite of the wave radiation into the adjacent liquid, a large group of Lamb waves are able to propagate along piezoelectric plates (quartz, LiNbO3, LiTaO3) coated with a liquid layer (distilled water H2O). When the layer freezes, most of the group’s waves increase their losses, essentially forming an acoustic response towards water-to-ice transformation. Partial contributions to the responses originating from wave propagation, electro-mechanical transduction, and wave scattering were estimated and compared with the coupling constants, and the vertical displacements of the waves were calculated numerically at the water–plate and ice–plate interfaces. The maximum values of the responses (20–30 dB at 10–100 MHz) are attributed to the total water-to-ice transformation. Time variations in the responses at intermediate temperatures were interpreted in terms of a two-phase system containing both water and ice simultaneously. The results of the paper may turn out to be useful for some applications where the control of ice formation is an important problem (aircraft wings, ship bodies, car roads, etc.).

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Liu, Yuhan, and Shuanggen Jin. "Ionospheric Rayleigh Wave Disturbances Following the 2018 Alaska Earthquake from GPS Observations." Remote Sensing 11, no. 8 (April 13, 2019): 901. http://dx.doi.org/10.3390/rs11080901.

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Big earthquakes often excite the acoustic resonance between the earth’s surface and the lower atmosphere. The perturbations can propagate upward into the ionosphere and trigger ionospheric anomalies detected by dual-frequency GPS observations, but coseismic ionospheric disturbance (CID) directivity and mechanism are not clear. In this paper, the ionospheric response to the Mw = 7.9 Alaska earthquake on 23 January 2018 is investigated from about 100 continuous GPS stations near the epicenter. The fourth-order zero-phase Butterworth band-pass filter with cutoffs of 2.2 mHz and 8 mHz is applied to obtain the ionospheric disturbances. Results show that the CIDs with an amplitude of up to 0.06 total electron content units (TECU) are detected about 10 min after the Alaska earthquake. The CIDs are as a result of the upward propagation acoustic waves triggered by the Rayleigh wave. The propagation velocities of TEC disturbances are around 2.6 km/s, which agree well with the wave propagation speed of 2.7 km/s detected by the bottom pressure records. Furthermore, the ionospheric disturbances following the 2018 Mw = 7.9 Alaska earthquake are inhomogeneous and directional which is rarely discussed. The magnitude of ionospheric disturbances in the western part of the epicenter is more obvious than in the eastern part. This phenomenon also corresponds to the data obtained from the seismographs and bottom pressure records (BPRs) at the eastern and western side of the epicenter.

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Lu, Tingting, Shuai Wang, Hao Zhang, Lingwei Xu, and T. Aaron Gulliver. "Design of Bulk Acoustic Wave Filters for Beidou Receiver." Journal of Circuits, Systems and Computers 24, no. 02 (November 27, 2014): 1550018. http://dx.doi.org/10.1142/s0218126615500188.

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Based on the thin-film bulk acoustic resonator (FBAR) technology, a new narrow-band bulk acoustic wave (BAW) filter for Beidou B1 band receiver is designed. The aluminum nitride thin film is used as a piezoelectric layer. The Mason model of air-gap TFBAR (AGR) resonators is established in advanced design system to investigate the relationship between electrical impedance and physical parameters. The simulation results illustrate the effect of the area of parallel unit and the number of resonators on the performance of the BAW filters. By changing the series-parallel unit series and area ratio, the pass band of the BAW filter can reach 1556–1566 MHz, and the out-of-band rejection and the insertion loss can reach 47.5 dB and 3.0 dB, respectively.

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Sujarittam, Krit, and James Choi. "Calibration of a focused passive cavitation detector using bubble shock waves." Journal of the Acoustical Society of America 151, no. 4 (April 2022): A31. http://dx.doi.org/10.1121/10.0010558.

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In microbubble-mediated therapeutic ultrasound, a focused passive cavitation detector (PCD) is often used to measure the bubbles’ acoustic emissions, providing useful signals for treatment monitoring. However, calibrating a spherically focused PCD is challenging, due to the difficulty of generating a spherical wave that matches the PCD’s surface curvature. Here, a PCD was calibrated using broadband shock waves generated by inertial collapses of single microbubbles. Microbubbles were diluted to a very low concentration, flowed through a wall-less gel channel, and sonicated using single-cycle, 0.5-MHz-centre-frequency, 1-MPa acoustic pulses. The focused PCD to be calibrated and a reference needle hydrophone captured their emissions. The sensitivity and phase response of the PCD relative to the reference hydrophone was calculated from the single bubble signals. For comparison, the PCD was also calibrated using a focused emitter as a sound source (Rich and Mast, JASA , 2015). The nominal PCD sensitivities obtained using the two methods agreed within 1% ± 14% within the PCD’s bandwidth (2–10 MHz). The calibration data from the bubble method was then used to correct the PCD’s signal distortions. Our method recovered the impulse waveform of the bubble-generated shock wave from the raw PCD signal, where such a waveform was not previously observed.

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Pfaffenberger, Stefan, Branka Devcic-Kuhar, Karem El-Rabadi, Martin Gröschl, Walter Speidl, Thomas Weiss, Kurt Huber, et al. "2MHz ultrasound enhances t-PA-mediated thrombolysis: comparison of continuous versus pulsed ultrasound and standing versus travelling acoustic waves." Thrombosis and Haemostasis 89, no. 03 (2003): 583–89. http://dx.doi.org/10.1055/s-0037-1613390.

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SummaryIn addition to fibrinolytic enzymes, ultrasound has the potential to enhance thrombolysis. High frequency ultrasound has the advantage that a combination of diagnostic and therapeutic ultrasound with only one device is possible. Therefore, we investigated the optimal high frequency (2 MHz) ultrasound field characteristics and application mode in vitro. Continuous ultrasound significantly enhanced rt-PA mediated thrombolysis: in a travelling wave field thrombolysis was augmented by 49.0 ± 14.7% and in a standing wave field by 34.8 ± 7.3%. In an intermittent application mode (1Hz, 10Hz, 100Hz, 1kHz) most efficient results were obtained for both wave fields using 1 Hz (46.4 ± 10.7% and 39.1 ± 6.6%, respectively). Referring to a possible in vivo application our in vitro data suggests that an intermittent application of a 2 MHz high frequency ultrasound using a travelling wave field would be the most potent application for lysing blood clots.

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Li, Yuanyuan, Meng Shao, Bei Jiang, and Le Cao. "Surface acoustic wave pressure sensor and its matched antenna design." Measurement and Control 52, no. 7-8 (June 21, 2019): 947–54. http://dx.doi.org/10.1177/0020294019857744.

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Interdigital transducer and signal transmission in surface acoustic wave pressure sensor design is one of the difficulties in sensor design. The transmission antenna is an important design indicator to determine the wireless function of the sensor. In this paper, we simulated the design of the interdigital transducer of surface acoustic wave pressure sensor through COMSOL and analyzed the relationship between the eigenfrequency of the single-pair interdigital model and the interdigital electrode. Then, we obtained the design of the interdigital electrode with error of 0.01 MHz. We also simulated the size, bandwidth, impedance matching, and other parameters of antenna through high frequency structure simulator, and a matching dipole transmission antenna was designed and miniaturized. When the bandwidth is satisfied, the control matching impedance error is within [Formula: see text], and it is verified that the antenna satisfies the signal transmission requirement of the surface acoustic wave pressure sensor. This design provides a more comprehensive approach to the design of interdigital transducers and signal transmission for the field of surface acoustic wave measurement pressure.

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Snively, Jonathan B., Roberto Sabatini, Donna A. Calhoun, Christopher J. Heale, Pavel A. Inchin, and Matthew D. Zettergren. "Modeling of acoustic and gravity wave interactions, coupling, and observables above meteorological systems." Journal of the Acoustical Society of America 151, no. 4 (April 2022): A161. http://dx.doi.org/10.1121/10.0010975.

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Meteorology, especially strong tropospheric convection, is widely appreciated to generate broad spectra of acoustic and gravity waves (AWs and GWs or, together, AGWs). These include GWs with scales of tens to hundreds of kilometers and periods of ∼5 min to hours, that readily propagate upward, reach high altitudes (often to the lower-thermosphere), and grow to large amplitudes so that they may evolve nonlinearly prior to being overcome by dissipation. Strong convective dynamics, e.g., thunderstorms and tornadoes, are also known to radiate AWs at very low infrasonic frequencies (e.g., 0.1 Hz down to ∼4 mHz) that reach high altitudes and may be detectable in fluctuations of the atmosphere and ionosphere [e.g., Nishioka et al. (2013); Heale et al. (2019)]. The breaking of strong GW fields may also generate secondary AWs and, more generally, AGWs [Snively (2017); Heale et al. (2021)]. Together, convection and secondary AGW processes contribute to a broad spectrum of AWs with ∼mHz periods that are readily detectable at high altitudes and in pressure signals also measured at ground. Although AWs are excluded from traditional numerical weather prediction models, we report on models and simulation experiments designed to capture AW/AGW evolutions and their resulting observable signatures. In particular, we review and highlight scenarios by which ∼mHz AWs may reveal source processes of interest, as well as the opportunities to use atmospheric and ionospheric signals of AWs/AGWs as complement to ground-based infrasound recordings.

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Santamaria, I. C., and T. Van Doorsselaere. "High frequency generation in the corona: Resonant cavities." Astronomy & Astrophysics 611 (March 2018): A10. http://dx.doi.org/10.1051/0004-6361/201731016.

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Aims. Null points are prominent magnetic field singularities in which the magnetic field strength strongly decreases in very small spatial scales. Around null points, predicted to be ubiquitous in the solar chromosphere and corona, the wave behavior changes considerably. Null points are also responsible for driving very energetic phenomena, and for contributing to chromospheric and coronal heating. In previous works we demonstrated that slow magneto-acoustic shock waves were generated in the chromosphere propagate through the null point, thereby producing a train of secondary shocks escaping along the field lines. A particular combination of the shock wave speeds generates waves at a frequency of 80 MHz. The present work aims to investigate this high frequency region around a coronal null point to give a plausible explanation to its generation at that particular frequency. Methods. We carried out a set of two-dimensional numerical simulations of wave propagation in the neighborhood of a null point located in the corona. We varied both the amplitude of the driver and the atmospheric properties to investigate the sensitivity of the high frequency waves to these parameters. Results. We demonstrate that the wave frequency is sensitive to the atmospheric parameters in the corona, but it is independent of the strength of the driver. Thus, the null point behaves as a resonant cavity generating waves at specific frequencies that depend on the background equilibrium model. Moreover, we conclude that the high frequency wave train generated at the null point is not necessarily a result of the interaction between the null point and a shock wave. This wave train can be also developed by the interaction between the null point and fast acoustic-like magneto-acoustic waves, that is, this interaction within the linear regime.

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Naruse, Kengo, and Yuji Watanabe. "Ultrasonic Plastic Welding at 1.2 MHz using a Surface Acoustic Wave Device." Japanese Journal of Applied Physics 45, no. 5B (May 25, 2006): 4812–15. http://dx.doi.org/10.1143/jjap.45.4812.

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Gusev, Michael E., and Yuri N. Zakharov. "Holographic measurement of surface acoustic wave parameters in crystals." Modern Electronic Materials 5, no. 3 (September 12, 2019): 107–14. http://dx.doi.org/10.3897/j.moem.5.3.51936.

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The theoretical basis of a specialized technique for applying digital holographic interferometry to measure the parameters of surface acoustic waves is presented, a measuring system for visualization and quantitative analysis of the parameters of ultralow-amplitude high-frequency oscillations arising in electronic devices using surface acoustic waves is developed, and experimental results of the study of surface acoustic waves in crystals of lithium niobate are obtained. In this case, to ensure the possibility of recording precision double-exposure interferograms of high-frequency surface acoustic waves, a picosecond pulsed laser with two-stage frequency multiplication was used as a radiation source, and to increase the spatial resolution of the system with the possibility of observing a wide field of view, an adjustable optical zoom of the incoming image was applied to the matrix input (based on charge-coupled devices) of the recording camera and digital zoom was used for obtained interferogram. We achieved the measuring sensitivity of the surface acoustic waves amplitude and spatial-temporal resolution allowing visualization and measurement of surface acoustic waves with amplitudes of the order of 1 nm and frequencies of the order of 10 MHz, which is far beyond the capabilities of standard methods of holographic interferometry.

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Rapoport, Yuriy G., Oleg K. Cheremnykh, Volodymyr V. Koshovy, Mykola O. Melnik, Oleh L. Ivantyshyn, Roman T. Nogach, Yuriy A. Selivanov, et al. "Ground-based acoustic parametric generator impact on the atmosphere and ionosphere in an active experiment." Annales Geophysicae 35, no. 1 (January 5, 2017): 53–70. http://dx.doi.org/10.5194/angeo-35-53-2017.

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Abstract. We develop theoretical basics of active experiments with two beams of acoustic waves, radiated by a ground-based sound generator. These beams are transformed into atmospheric acoustic gravity waves (AGWs), which have parameters that enable them to penetrate to the altitudes of the ionospheric E and F regions where they influence the electron concentration of the ionosphere. Acoustic waves are generated by the ground-based parametric sound generator (PSG) at the two close frequencies. The main idea of the experiment is to design the output parameters of the PSG to build a cascade scheme of nonlinear wave frequency downshift transformations to provide the necessary conditions for their vertical propagation and to enable penetration to ionospheric altitudes. The PSG generates sound waves (SWs) with frequencies f1 = 600 and f2 = 625 Hz and large amplitudes (100–420 m s−1). Each of these waves is modulated with the frequency of 0.016 Hz. The novelty of the proposed analytical–numerical model is due to simultaneous accounting for nonlinearity, diffraction, losses, and dispersion and inclusion of the two-stage transformation (1) of the initial acoustic waves to the acoustic wave with the difference frequency Δf = f2 − f1 in the altitude ranges 0–0.1 km, in the strongly nonlinear regime, and (2) of the acoustic wave with the difference frequency to atmospheric acoustic gravity waves with the modulational frequency in the altitude ranges 0.1–20 km, which then reach the altitudes of the ionospheric E and F regions, in a practically linear regime. AGWs, nonlinearly transformed from the sound waves, launched by the two-frequency ground-based sound generator can increase the transparency of the ionosphere for the electromagnetic waves in HF (MHz) and VLF (kHz) ranges. The developed theoretical model can be used for interpreting an active experiment that includes the PSG impact on the atmosphere–ionosphere system, measurements of electromagnetic and acoustic fields, study of the variations in ionospheric transparency for the radio emissions from galactic radio sources, optical measurements, and the impact on atmospheric aerosols. The proposed approach can be useful for better understanding the mechanism of the acoustic channel of seismo-ionospheric coupling.

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Karapetyan, G. Ya, V. E. Kaydashev, M. E. Kutepov, T. A. Minasyan, V. A. Kalinin, V. O. Kislitsyn, and E. M. Kaidashev. "Tunable high-Q SAW resonator loaded on a changing capacitance." Journal of Advanced Dielectrics 10, no. 01n02 (February 2020): 2060009. http://dx.doi.org/10.1142/s2010135x20600097.

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A tunable high-Q surface acoustic wave (SAW) resonator in the form of several parallel-connected interdigital transducers loaded on a varying capacitance on lithium niobate substrates was developed and studied. The working frequency range was 90–2450[Formula: see text]MHz. A method of calculating such resonators, considering losses in the metal film as well as losses due to the propagation of SAWs and transformations into bulk waves is proposed. Such a design allows one to obtain a quality factor over 5000 in the frequency range 2400–2483[Formula: see text]MHz. The resonant frequency shifts by 600[Formula: see text]kHz when the capacitance changes by [Formula: see text]% of the value of 21[Formula: see text]pF (or 32[Formula: see text]ppm/pF) and has an almost linear character.

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Luey, Kenneth, Michael Fay, and Rusty Sly. "Measurement of Molecular Film Contamination Using Surface Acoustic Wave Microbalances." Journal of the IEST 47, no. 2 (September 14, 2004): 25–38. http://dx.doi.org/10.17764/jiet.47.2.u7j41141n4g824l5.

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To ensure the cleanliness of sensitive spacecraft systems, the contamination environment in aerospace cleanrooms and highbays is closely monitored. In this paper, we report the testing and evaluation of a commercially available molecular contamination monitor consisting of a 200-MHz surface acoustic wave microbalance (SAWM). SAWMs were placed into four different aerospace facilities with markedly different environments. SAWMs measured distinctly different molecular film accretion rates consistent with the levels of contamination control and activity in each facility. SAWM results were compared with nonvolatile residue (NVR) accretion rates measured by witness plates. Witness plate data yielded a higher NVR accretion rate than microbalance data. We present evidence that this difference is due to the detection limit of the witness plate analysis technique and not to a fundamental difference in surface deposition processes.

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KONNO, Tomokatsu, Zhongqing BAO, Motoaki HARA, and Hiroki KUWANO. "J2230204 300 MHz band Oscillator type strain sensors using surface acoustic wave resonators." Proceedings of Mechanical Engineering Congress, Japan 2014 (2014): _J2230204——_J2230204—. http://dx.doi.org/10.1299/jsmemecj.2014._j2230204-.

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Hamidon, Mohd, Vlad Skarda, Neil White, Ferdinand Krispel, Peter Krempl, Michael Binhack, and Werner Buff. "High-temperature 434 MHz surface acoustic wave devices based on GaPO/sub 4/." IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control 53, no. 12 (December 2006): 2465–70. http://dx.doi.org/10.1109/tuffc.2006.194.

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Naruse, Kengo, Kiyomi Mori, and Yuji Watanabe. "Ultrasonic Joining of Au Foil using a 2.5 MHz Surface Acoustic Wave Device." Japanese Journal of Applied Physics 47, no. 5 (May 23, 2008): 4305–8. http://dx.doi.org/10.1143/jjap.47.4305.

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Nakano, Ken, Kazuhiro Hane, Shigeru Okuma, and Tadashi Eguchi. "Visualization of 50 MHz Surface Acoustic Wave Propagation Using Stroboscopic Phase-Shift Interferometry." Optical Review 4, no. 2 (March 1997): 265–69. http://dx.doi.org/10.1007/s10043-997-0265-0.

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Giffney, Timothy J., Y. H. Ng, and K. C. Aw. "A Surface Acoustic Wave Ethanol Sensor with Zinc Oxide Nanorods." Smart Materials Research 2012 (December 26, 2012): 1–4. http://dx.doi.org/10.1155/2012/210748.

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Surface acoustic wave (SAW) sensors are a class of piezoelectric MEMS sensors which can achieve high sensitivity and excellent robustness. A surface acoustic wave ethanol sensor using ZnO nanorods has been developed and tested. Vertically oriented ZnO nanorods were produced on a ZnO/128∘ rotated Y-cut LiNbO3 layered SAW device using a solution growth method with zinc nitrate, hexamethylenetriamine, and polyethyleneimine. The nanorods have average diameter of 45 nm and height of 1 μm. The SAW device has a wavelength of 60 um and a center frequency of 66 MHz at room temperature. In testing at an operating temperature of 270 with an ethanol concentration of 2300 ppm, the sensor exhibited a 24 KHz frequency shift. This represents a significant improvement in comparison to an otherwise identical sensor using a ZnO thin film without nanorods, which had a frequency shift of 9 KHz.

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WESTERMARK, Sara, Hans WIKSELL, Håkan ELMQVIST, Kjell HULTENBY, and Hans BERGLUND. "Effect of externally applied focused acoustic energy on clot disruption in vitro." Clinical Science 97, no. 1 (May 21, 1999): 67–71. http://dx.doi.org/10.1042/cs0970067.

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Application of low-frequency ultrasound for clot disruption has been suggested as a potential therapy to enhance thrombus dissolution, but the optimal mode for delivery of ultrasound with clot-disruptive properties has not yet been extensively explored. Target-specific effects are desirable and may be accomplished by focusing the ultrasound. Adequate focusing, however, requires a short wavelength. The aim of this study was to compare the clot-disruptive effects of different modalities of focused acoustic energy. An in vitro model (10 blood clots for each modality) was used to test the clot-disruptive capacity of (i) shock waves generated in an electrohydraulic lithotriptor; (ii) focused continuous ultrasound of frequency 1.1 MHz, delivered from a specially constructed piezoelectric transducer; and (iii) focused pulse-modulated ultrasound of frequency 1.1 MHz delivered from the same transducer. Exposure to 30 s of focused pulse-modulated ultrasound caused a marked reduction (99±2%) in clot weight compared with 30 shock waves (11±5%) or 30 s exposure to focused continuous wave ultrasound (11±6%) (P< 0.0001). The observed marked and rapid disruptive effect on blood clots of focused high-frequency ultrasound indicates an alternative approach for external ultrasound-mediated thrombus destruction in vivo. The focused pulse-modulated technique has potential to exhibit the desired effect in a well-defined target volume and provides the means for control of the average power.

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Ulug, Bulent, Furkan Kuruoğlu, Yeşim Yalçın, Ayşe Erol, Fahrettin Sarcan, Ali Şahin, and Ahmet Cicek. "Surface acoustic wave quasi-Bessel beams generated by symmetrically tilted interdigital transducers." Journal of Physics D: Applied Physics 55, no. 22 (March 7, 2022): 225303. http://dx.doi.org/10.1088/1361-6463/ac570c.

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Abstract Formation of surface acoustic wave (SAW) quasi-Bessel beams on a piezoelectric substrate through superposition of plane waves generated by interdigital transducers tilted symmetrically about the propagation axis is numerically and experimentally demonstrated. Acting as an axicon, the tilted transducers provide a facile way for quasi-Bessel beam generation. Finite-element method simulations reveal that non-diffracting Bessel beams, whose length and width are 193 and 1.38 wavelengths, respectively, can be obtained on a YX-128∘ lithium niobate substrate for an axicon angle of 15 degrees. The corresponding values for 20 degrees are 146 and 1.05 wavelengths, respectively. For a wavelength of approximately 300 micrometers, transmission spectra show that Bessel beam formation can be achieved at frequencies around 13.3 MHz. Bessel beam is visualized through a thin liquid film of methanol on the substrate. SAW Bessel beams can be utilized in acoustophoresis in microfluidic systems and sensing applications.

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Journal articles on the topic 'MHz acoustic wave'

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