Top PDF Piezoelectric shear wave resonator and method of making same

Piezoelectric shear wave resonator and method of making same

Piezoelectric shear wave resonator and method of making same

An acoustic shear wave resonator comprising a piezoelectric film having its C-axis substantially inclined from the film normal such that the shear wave coupling coefficient significantly exceeds the longitudinal wave coupling coefficient, whereby the film is capable of shear wave resonance, and means for exciting said film to resonate. The film is prepared by deposition in a dc planar magnetron sputtering system to which a

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Environmentally stable reactive alloy powders and method of making same

Environmentally stable reactive alloy powders and method of making same

Apparatus and method for making powder from a metallic melt by atomizing the melt to form droplets and reacting the droplets downstream of the atomizing location with a reactive gas. The droplets are reacted with the gas at a temperature where a solidified exterior surface is formed thereon and where a protective refractory barrier layer (reaction layer) is formed whose penetration into the droplets is limited by the presence of the solidified surface so as to avoid selective reduction of key reactive alloyants needed to achieve desired powder end use properties. The barrier layer protects the reactive powder particles from environmental constituents such as air and water in the liquid or vapor form during subsequent fabrication of the powder to end-use shapes and during use in the intended service environment.
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Method of making a piezoelectric shear wave resonator

Method of making a piezoelectric shear wave resonator

An acoustic shear wave resonator comprising a piezoelectric film having its C-axis substantially inclined from the film normal such that the shear wave coupling coefficient significantly exceeds the longitudinal wave coupling coefficient, whereby the film is capable of shear wave resonance, and means for exciting said film to resonate. The film is prepared by deposition in a dc planar magnetron sputtering system to which a

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The Peano-series solution for modeling shear horizontal waves in piezoelectric plates

The Peano-series solution for modeling shear horizontal waves in piezoelectric plates

Abstract. The shear horizontal (SH) wave devices have been widely used in electro- acoustic. To improve their performance, the phase velocity dispersion and the electromechanical coupling coefficient of the Lamb wave should be calculated exactly in the design. Therefore, this work is to analyze exactly the Lamb waves polarized in the SH direction in homogeneous plate pie.zoelectric material (PZT-5H). An alternative method is proposed to solve the wave equation in such a structure without using the standard method based on the electromechanical partial waves. This method is based on an analytical solution, the matricant explicitly expressed under the Peano series expansion form. Two types of configuration have been addressed, namely the open circuited and the short circuited. Results confirm that the SH wave provides a number of attractive properties for use in sensing and signal processing applications. It has been found that the phase velocity remains nearly constant for all values of h/λ (h is the plate thickness, λ the acoustic wavelength). Secondly the SH 0 wave mode can provide very
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Design of Piezoelectric Aluminum Nitride MEMS Resonator

Design of Piezoelectric Aluminum Nitride MEMS Resonator

Fig. 1 shows the geometry of a rectangular plate resonator with tethers (of same materials) attached at λ/4 position which makes them quarter wave tether. The main purpose of using tether in the design of resonator is to make the mode shape more stable by countermanding spurious resonances and making the structure capable of withstanding higher power [3]. A more efficient way of building reflectors is to introduce a material mismatch between the mechanical structure and the anchors [4].

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Harmonic analysis of lossy piezoelectric composite transducers using the plane wave expansion method

Harmonic analysis of lossy piezoelectric composite transducers using the plane wave expansion method

In the next section the geometry of the transducer is described in terms of a Fourier series and then the PWE method and associated boundary conditions are briefly outlined. It follows the derivation of Wilm et al [18], with an alternative notation for the Fourier coefficient indexing. As such only a brief outline is given to clarify the later discussions on the inclusion of viscoelastic loss and numerical implementation issues. In Section 3 the inclusion of viscoelastic loss into the model is described, followed by a discussion on the use of scaling and regularisation in the method’s implementation. In Section 4 a comparison between the PWE method, FE modelling and experimentally measured behaviour is reported. Finally, a composite transducer with a high shear loss passive phase is examined. Dispersion curves, electrical impedance plots and a modal analysis using displacement and Poynting vector profiles are used to discuss the operating characteristics.
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Piezoelectric Resonator Study of the Viscosity of Interfacial Layers at Gold Electrode Surface in Perchloric Acid, Tetrafluoroborate and Sulphate Solutions

Piezoelectric Resonator Study of the Viscosity of Interfacial Layers at Gold Electrode Surface in Perchloric Acid, Tetrafluoroborate and Sulphate Solutions

The purpose of present work is to further examine the generality of the character of interfacial liquid viscosity dependence on the potential by using greater variety of solutions like containing sodium sulphate, perchloric acid and sodium tetrafluoroborate. For this purpose, dual-quartz resonator (two resonators with differently textured surfaces in a monolithic sensor), quartz resonator admittance and EIS techniques are used. Also, the purpose is to discuss the change of viscosity with the distance from electrode surface by using results of present work and other published findings. It should be noted that piezoelectric resonator only probes the region close to the surface. The shear wave evanescently decays into liquid according to exponential law [10, 11]. Hence in piezoelectric resonator measurement interfacial properties are determined by averaging over the velocity decay length scale of the damped shear wave radiated into the liquid by the resonator [11]. This decay length
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Piezoelectric Device for Measuring Shear Wave Velocity of Soils and Evaluation of Low and High Strain Shear Modulus

Piezoelectric Device for Measuring Shear Wave Velocity of Soils and Evaluation of Low and High Strain Shear Modulus

The primary consolidation time can be assessed with the evolution of shear wave velocity and the slope of the resistance-log time curve (Lee et al. 2008). Robertson et al. (1995) proposed the values of normalized shear-wave velocity to evaluate the in-situ state of cohesionless soils. This helped in identifying the boundary between contracting (loose) or dilatant (dense) sands. Shear wave velocity is a key soil property defining the state parameters of sandy soils. An indirect relationship between friction angle, void ratio, and shear wave velocity for sandy soils has been developed by Cha and Cho (2007), thus presenting an alternate method of estimating the shear strength of sandy soils through the shear wave velocity measurements. Fioravante et al. (1998) has used Shear wave velocity to estimate the coefficient of the earth pressure at rest (Kₒ). Both vertical and lateral variations in shear wave velocity are often used in 1D and 2D analyses of soil deposits and stress deformation analyses that provide key input for seismic design (Hunter and Crow, 2012). Shear wave velocity was also used as a tool to evaluate stress-induced anisotropy and inherent soil anisotropy (Lee et al. 2008); Pennington et al. (1997); Yamashita and Suzuki (2001); Kuwano and Jardine (2002); Zeng and Grolewski (2005); Ismail and Rammah (2006).
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The Design of Surface Acoustic Wave Receiving Circuit Based on Piezoelectric Transducer

The Design of Surface Acoustic Wave Receiving Circuit Based on Piezoelectric Transducer

Many researchers studied the structures and functions of SAW receiving cir- cuits. Gao et al. [5] designed a receiving circuit with IQ demodulator chip, low-noise baseband amplifier, ADC driver, high-speed ADC, FPGA and SRAM, combined with transmitting circuit to constitute a SAW RFID system. Zhou et al. [6] make use of the method of lock-in amplifying to pick up the weak signal from noise, they solve the problem on amplifying the output signal of SAW gy- roscope. Kim et al. [7] introduces the transmission or out of band blocker signal canceller architectures in receiver systems. Owaki [8] designed a type of device includes a piezoelectric substrate and an IDT electrode provided on the piezoe- lectric substrate. Funami et al. [9] made a communication equipment includes SAW resonator, filter and duplexer. Lei et al. [10] fabricated a device with U wave band (860 MHz) frequency modulation wireless microphone transmitter and receiver and it can achieve in the wide use of wireless amplifier system in multimedia classrooms.
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Linear and nonlinear shear wave propagation in viscoelastic media

Linear and nonlinear shear wave propagation in viscoelastic media

a viscoelastic to a simple viscous fluid. We show that the maximum normal and shear wall stresses exhibit strong peaks at discrete depths, with a significant drop between the peaks, except in the viscous fluid limit. For the upper convected Maxwell model, the frequency-locked response is explicitly solvable for a finite depth geometry [22], and thus we have explicit formulas for all wall stress transfer functions versus all parameters. The dependence on layer height happens to be the simplest to analyze and identify the nature of the peaks and valleys versus height. We then extend the results to all other parameters by numerical evaluation of the explicit formulas. Finally, to show robustness of the behavior, we shift to the Giesekus model. We generate parameter sweeps of the stress transfer functions, which now require numerical simulations of the governing system of nonlinear partial differential equations at each fixed parameter set, a parameter sweep of runs, followed by post-processing of the transfer functions. The oscillatory structure in these boundary stress signals is shown to persist; as mentioned earlier, this is indeed the context in which the phenomena were discovered, and the simplification to the UCM model was taken to gain an analytical understanding.
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Near surface shear wave velocity in Bucharest, Romania

Near surface shear wave velocity in Bucharest, Romania

Abstract. Bucharest, the capital of Romania with nearly 2 1/2 million inhabitants, is endangered by the strong earth- quakes in the Vrancea seismic zone. To obtain information on the near surface shear-wave velocity (Vs) structure and to improve the available microzonations we conducted seismic refraction measurements in two parks of the city. There the shallow Vs structure is determined along five profiles, and the compressional-wave velocity (Vp) structure is obtained along one profile. Although the amount of data collected is limited, they offer a reasonable idea about the seismic velocity distri- bution in these two locations. This knowledge is useful for a city like Bucharest where seismic velocity information so far is sparse and poorly documented. Using sledge-hammer blows on a steel plate and a 24-channel recording unit, we ob- serve clear shear-wave arrivals in a very noisy environment up to a distance of 300 m from the source. The Vp model along profile 1 can be correlated with the known near surface sedimentary layers. Vp increases from 320 m/s near the sur- face to 1280 m/s above 55–65 m depth. The Vs models along all five profiles are characterized by low Vs (<350 m/s) in the upper 60 m depth and a maximum Vs of about 1000 m/s below this depth. In the upper 30 m the average Vs 30 varies from 210 m/s to 290 m/s. The Vp-Vs relations lead to a high Poisson’s ratio of 0.45–0.49 in the upper ∼ 60 m depth, which is an indication for water-saturated clayey sediments. Such ground conditions may severely influence the ground motion during strong Vrancea earthquakes.
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A well-posedness result for a shear wave propagation model

A well-posedness result for a shear wave propagation model

dened a basic model to emulate shear waves propagating from a coronary.. stenosis through a homogeneous, soft-tissue like medium..[r]

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Validity of the Refraction Microtremors (ReMi) Method for Determining Shear Wave Velocities for Different Soil Types in Egypt

Validity of the Refraction Microtremors (ReMi) Method for Determining Shear Wave Velocities for Different Soil Types in Egypt

ReMi data at this site was acquired using a 12 channel seismograph. Fifty “noise records” were obtained every 8 seconds for a total of 400 sec microtremors data. Fig- ures 5 and 6 show the velocity spectrum (P-f image) and corresponding dispersion curve and picks obtained for Damietta site. The Picks were then modeled to produce the shear-wave velocity model as shown in Figure 7. The site is full of noise generated from loading and unloading of containers from ships inside the harbor and also from heavy traffic. The soil of Damietta (one of the weakest soils in Egypt) show average shear wave veloc- ity between 120 - 200 m/s Figure 7. Both crosshole and ReMi models show a low-velocity zone exist at depths between 13 - 28 m. This layer is confirmed from drilling data (very soft clay).
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A new approach for the automatic detection of shear-wave splitting

A new approach for the automatic detection of shear-wave splitting

Applications of the shear-wave splitting technique to geothermal fields have been extensively documented (e.g. Lou and Rial, 1994, 1995, 1997; Rial and Lou, 1996; Lou et al., 1997; Erten and Rial, 1998, 1999; Vlahovic et al., 2001). Although in principle straightforward, the analysis of shear- wave splitting for the purpose of crack detection is laborious, requiring careful processing of a large number of 3-component seismograms from all azimuths around every station. This is because a number of undesirable effects, such as the presence of multiple orientations of cracks between source and receiver, complicated earthquake source time history, strong medium heterogeneity, thick weathered surface layer or rugged surface topography, among others, may strongly distort the signal, making the identification of crack-induced splits difficult to impossible. The correct measurement polarization and delay time often requires experience, diligence and dedication for the task is very time consuming. It is therefore a seismologist’s dream to develop new skills to accomplish the measurement automatically, ultimately simplifying the monitoring of the field's subsurface crack system during exploration and into production
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High-Q Reflection Notch Method for MM Wave Measurements of Large Dielectric Losses Using a Stack Resonator: Analysis and Simulations

High-Q Reflection Notch Method for MM Wave Measurements of Large Dielectric Losses Using a Stack Resonator: Analysis and Simulations

Basic implementation of the measurement method (similar to [12– 16]) consists in measuring the reflection power P ref as a function of frequency f for the liquid of unknown ² r and ² i assuming both the stack geometry and the complex permittivity of plates are known. Then, by comparing measurements with simulations, we could recover both the real and imaginary parts of complex permittivity of liquid. Other ways of parameter extraction are possible, e.g., by evaluating the reflection notch frequency f n and the notch quality factor Q n from the measured

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Development of Polymer-Based Dielectric Resonator Antennas for Millimeter-Wave Applications

Development of Polymer-Based Dielectric Resonator Antennas for Millimeter-Wave Applications

Dielectric Resonator Antennas (DRAs) offer many appealing features such as larger impedance bandwidth and higher radiation efficiency due to the lack of conductor and surface wave losses [1]. Nevertheless, compared to their metallic counterparts, fabrication of DRAs is challenging since they have traditionally been made of high permittivity ceramics, which are naturally hard and extremely difficult to machine. The fabrication of these three dimensional structures is even more difficult at millimetre-wave frequencies where the size of the antenna is reduced to the millimetre or sub-millimetre range, and tolerances to common manufacturing imperfections are even smaller requiring a wideband antenna to compensate the possible inaccuracies. Several methods have been considered in the literature to increase the bandwidth of DRAs. Exotic shapes [2–4], parasitic metal strips [5– 7], and stacking parasitic DRAs [8–10], are among the most common ways, all of which are less suitable for millimetre-wave fabrication due to their complicated structures and use of metallic parts.
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Finite-difference modelling to evaluate seismic P-wave and shear-wave field data

Finite-difference modelling to evaluate seismic P-wave and shear-wave field data

The vertical hydraulic vibrator sources MHV2.7 and HVP- 30 have proven their ability to reach reflectors at least 2 km deep (Buness et al., 2009). The LIAG shear-wave vibra- tor source MHV-4S has been able to generate clear reflec- tions at least as deep as 200 m in fluviatile and marine deposits (Polom et al., 2010). Sauvin et al. (2014) used a wheelbarrow-mounted microvibrator source for the anal- ysis of quick clays. Their data show clear reflections from 40 m below ground level within fluviatile and marine sedi- ments. In the underlying bedrock, reflections can be traced down to 120 m depth. Malehmir et al. (2013) report clear reflections in a similar environment from at least 40 m be- low ground level with the same source. This means that even small sources are able to create reflections from at least 40 m below the source. Pugin et al. (2009b) used an IVI Minivib on a minibuggy carrier, which is comparable to the MHV- 4S. They show SH-wave reflections down to about 50 m in glacial deposits before reaching the bedrock. In the light of these studies, the MHV-4S source can be expected to be strong enough to image the glacially overworked deposits
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Quarter Wave Resonator based Microstrip Bandpass Filter using Asymmetrical coefficients

Quarter Wave Resonator based Microstrip Bandpass Filter using Asymmetrical coefficients

In the first section of this paper, the introduction of microstrip bandpass filter was given. In the second section of this paper, the general approach of quarter-wave resonator based bandpass filter design is discussed. In Section III the performance analysis of bandpass filter using the existing and proposed coefficients was done using ADS co-simulation. The proposed work was concluded in section IV.

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Digital Holographic Method for Piezoelectric Transformers Vibration Analysis

Digital Holographic Method for Piezoelectric Transformers Vibration Analysis

h  M    h e  (6) to get a filtered digital hologram h. Afterwards, the processed hologram is reconstructed using Fresnel transform (1) and the intensity distribution is calculated with use of formula (2). The interferogram reconstructed from the processed hologram h has a much higher signal to noise ratio and strongly suppressed DC term compared to the interferogram reconstructed from a single hologram. To suppress speckle noise in interferograms generated by coherent illumination, some advanced filtering methods can be used [11]. Low overall noise is a key factor to get the very high resolution of this method. Since the reflectance of the piezoelectric transformer is not uniform along the entire surface, the reference interferogram with no frequency shift of the reference
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A Novel and Accurate Method for Designing Dielectric Resonator Filter

A Novel and Accurate Method for Designing Dielectric Resonator Filter

Based on the presented method, a DR filter is designed, implemented and fabricated and the results are provided. The fabricated filter has an exclusive feature, i.e., it contains no screw for frequency tuning and it gives out the desired result without a need to modification.

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