Showing papers on "Interdigital transducer published in 2018"

Development of chipless, wireless current sensor system based on giant magnetoimpedance magnetic sensor and surface acoustic wave transponder

Abstract: A chipless, wireless current sensor system was developed using a giant magnetoimpedance (GMI) magnetic sensor and one-port surface acoustic wave (SAW) reflective delay line for real-time power monitoring in a current-carrying conductor. The GMI sensor has a high-quality crystalline structure in each layer, which contributes to a high sensitivity and good linearity in a magnetic field of 3–16 Oe. A 400 MHz RF energy generated from the interdigital transducer (IDT)-type reflector on the one-port SAW delay line was used as an activation source for the GMI magnetic sensor. The one-port SAW delay line replaces the presently existing transceiver system, which is composed of thousands of transistors, thus enabling chipless and wireless operation. We confirmed a large variation in the amplitude of the SAW reflection peak with a change in the impedance of the GMI sensor caused by the current flow through the conductor. Good linearity and sensitivity of ~0.691 dB/A were observed for currents in the range 1–12 A. Coupling of Mode (COM) modeling and impedance matching analysis were also performed to predict the device performance in advance and these were compared with the experimental results.

Visualization of Surface-acoustic-wave Potential by Transmission-mode Microwave Impedance Microscopy

Abstract: Elastic waves propagating in piezoelectric materials are accompanied by a time-varying electric potential, which is of critical importance for acousto-electronic applications. The spatial mapping of such a potential at microwave frequencies is challenging since the characteristic length scale is determined by the acoustic wavelength of several micrometers. In this work, we report the visualization of surface acoustic waves (SAWs) on ferroelectric samples by transmission-mode microwave impedance microscopy (T-MIM). The SAW potential launched by the interdigital transducer is detected by the tip and demodulated by the microwave electronics as time-independent spatial patterns. Wave phenomena such as interference and diffraction are imaged and the results are in excellent agreement with the theoretical analysis. Our work opens up a new avenue to study various electromechanical systems in a spatially resolved manner.

Applicability Investigation of SAW Devices in the 3 to 5 GHz range

Abstract: This paper investigates applicability of new type SAW devices comprising a thin piezoelectric crystal plate and an acoustic energy confinement portion to the 3 to 5 GHz range unexplored for SAW industries. First, it is demonstrated that excellent performances even in the 3.5 GHz range are achievable by using a KrF stepper/scanner that has commonly used in SAW mass production lines when I.H.P. SAW (Incredible High-perfor-mance SAW), one of the new type SAW devices, is used. Next, the same interdigital transducer periodicity of the 3.5 GHz I.H.P.SAW is applied to an LLSAW devices, another new type SAW device, and it is revealed that good performance is still achievable even in the 5 GHz range.

A Novel Swimmer Actuator Via Leaky Surface Acoustic Wave

Abstract: Robotic swimmer represents a rapidly emerging and fascinating research area. Particularly, small size swimmer is attempt to be a drug carrier or fixer inside the human body. Simultaneously, acoustic microfluidics represents one of very few inertial phenomena that may actually play a significant role in microfluidic devices. In this study, a novel approach to the swimmer actuator via leaky surface acoustic wave (LSAW)is first proposed in the world. Surface acoustic wave is excited with a unidirectional interdigital transducer in the 128° y-rotated x-propagation lithium niobate substrate. The speed and propulsion of the swimmer are measured.

A Wireless Passive SAW Delay Line Temperature and Pressure Sensor for Monitoring Water Distribution System

Abstract: Wireless passive surface acoustic wave (SAW) sensor has been widely used in many applications. This paper presents a feasibility study on a designed wireless passive SAW delay line temperature and pressure sensor for monitoring water distribution systems. The substrate of the sensor node is a Y-Z orientation cut LiNbO 3 crystalline with 0.5 mm thickness. The Interdigital transducer (IDT) was fabricated centrally on the surface of the substrate with an antenna connected. There are three reflectors fabricated on the same surface of the IDT. One reflector is on one side and the other two are on the other side of the IDT. A simulated water pipe platform with testing devices was assembled to test the feasibility of the sensor node working in water pipe environment. The experimental result showed that the designed sensor worked properly but 4/5 amplitude of signals is lost compared to the experimental results in the open-air environment.

Surface Acoustic Wave Gyroscopic Effect in an Interdigital Transducer.

Abstract: The surface acoustic wave (SAW) gyroscopic effect in an interdigital transducer (IDT) deposited on a piezoelectric substrate is different from that in the piezoelectric substrate due to a reflection induced by IDT. In this work, an extended coupling-of-mode (COM) model including the gyroscopic effect and the reflection was developed to analyze the SAW gyroscopic effect. First, dispersion characteristics parameters of SAW were fitted according to the data derived using the finite element method (FEM). Then, variations of stop band edge frequency were calculated using the extended COM theory by integrating dispersion characteristics parameters into the COM model. We compared its results with those obtained via FEM analysis to confirm the proposed model’s validity. We found that the variation in stop band edge frequency related to gyroscope effect reached the maximum value with a zero reflectivity value. For split IDT, the sensitivity of gyroscope effect is 0.036 Hz/rad/s with a lower than 1% normalized thickness. Conversely, the value of sensitivity was almost zero for bidirectional IDT and electrode width controlled single-phase unidirectional transducer (EWC/SPUDT).

Non-destructive characterization of surfaces and thin coatings using a large-bandwidth interdigital transducer.

Abstract: This paper deals with non-destructive testing of thin layer structures using Rayleigh-type waves over a broad frequency range (25-125 MHz). The dispersion phenomenon was used to characterize a layer-on-substrate-type sample comprising a thin layer of platinum 100 nm thick on a silicon substrate. The originality of this paper lies in the investigation of different ways of generating surface acoustic waves (SAWs) with large bandwidth interdigital transducers (IDTs) as well as the development of a measuring device to accurately estimate the SAW phase velocity. In particular, this study focuses on comparing the performance (in terms of SAW amplitude and bandwidth) of different excitations imposed on IDTs. The three types of excitations are burst, impulse, and chirp. The interest of chirp excitation compared to the other two types was clearly demonstrated in terms of the SAW bandwidth and amplitude of displacement. With these IDT transducers, measurements could be performed over a wide frequency band (20-125 MHz), and consequently, dispersion curves could be obtained over a wide frequency band with a range of velocity variations in the order of 100 m/s. Under these conditions, an extremely accurate estimate of the phase velocity as a function of the frequency could be obtained using a Slant Stack transformation. Finally, from these experimental dispersion curves and theoretical dispersion curves, an accurate estimate of the thickness of the layer could be obtained by inversion. This estimated thickness was then confirmed using profilometer measurements.

Single-Input and Multiple-Output Surface Acoustic Wave Sensing for Damage Quantification in Piezoelectric Sensors.

Abstract: The main aim of the paper is damage detection at the microscale in the anisotropic piezoelectric sensors using surface acoustic waves (SAWs). A novel technique based on the single input and multiple output of Rayleigh waves is proposed to detect the microscale cracks/flaws in the sensor. A convex-shaped interdigital transducer is fabricated for excitation of divergent SAWs in the sensor. An angularly shaped interdigital transducer (IDT) is fabricated at 0 degrees and ±20 degrees for sensing the convex shape evolution of SAWs. A precalibrated damage was introduced in the piezoelectric sensor material using a micro-indenter in the direction perpendicular to the pointing direction of the SAW. Damage detection algorithms based on empirical mode decomposition (EMD) and principal component analysis (PCA) are implemented to quantify the evolution of damage in piezoelectric sensor material. The evolution of the damage was quantified using a proposed condition indicator (CI) based on normalized Euclidean norm of the change in principal angles, corresponding to pristine and damaged states. The CI indicator provides a robust and accurate metric for detection and quantification of damage.

Heat Transfer Characteristics of a Focused Surface Acoustic Wave (F-SAW) Device for Interfacial Droplet Jetting

Abstract: In this study, we investigate the interfacial droplet jetting characteristics and thermal stability of a focused surface acoustic wave device (F-SAW). An F-SAW device capable of generating a 20 MHz surface acoustic wave by applying sufficient radio frequency power (2–19 W) on a 128°-rotated YX-cut piezoelectric lithium niobate substrate for interfacial droplet jetting is proposed. The interfacial droplet jetting characteristics were visualized by a shadowgraph method using a high-speed camera, and a heat transfer experiment was conducted using K-type thermocouples. The interfacial droplet jetting characteristics (jet angle and height) were analyzed for two different cases by applying a single interdigital transducer and two opposite interdigital transducers. Surface temperature variations were analyzed with radio frequency input power increases to evaluate the thermal stability of the F-SAW device in air and water environments. We demonstrate that the maximum temperature increase of the F-SAW device in the water was 1/20 of that in the air, owing to the very high convective heat transfer coefficient of the water, resulting in prevention of the performance degradation of the focused acoustic wave device.

Transversely-excited film bulk acoustic resonator

Abstract: Acoustic resonator devices and filters are disclosed. An acoustic resonator includes a substrate and a piezoelectric plate having parallel front and back surfaces, the back surface attached to the substrate. An interdigital transducer (IDT) is formed on the front surface of the piezoelectric plate such that interleaved fingers of the IDT are disposed on a portion of the piezoelectric plate suspended over a cavity formed in the substrate.

Multielement Interdigital Transducers for Structural Health Monitoring

Abstract: This work presents an improved interdigital transducer for ultrasonic guided-wave generation and reception in structural health monitoring systems, where each finger constitutes an independent electrode that can be driven and sensed with a multichannel system. The new design aims at improving the versatility in wavelength selectivity of the classical interdigital transducer. Preliminary tests have shown that the fingers work correctly as a time-delayed periodic array.

Elastic wave device with sub-wavelength thick piezoelectric layer and high velocity layer

Abstract: Aspects of this disclosure relate to an elastic wave device. The elastic wave device includes a sub-wavelength thick piezoelectric layer, an interdigital transducer electrode on the piezoelectric layer, and a high velocity layer configured to inhibit an elastic wave from leaking from the piezoelectric layer at anti-resonance.

Frequency filter of uhf signal on magnetic waves

Abstract: FIELD: radio engineering.SUBSTANCE: invention relates to UHF electronics, in particular to instruments on magnetostatic waves, and can be used as a frequency filter. Essence of the invention lies in the fact that the frequency filter of the UHF signal on magnetostatic waves contains a magnetic element, which is a magnon crystal, having the form of an extended rectangle with pointed ends along the longitudinal axis and periodic geometric irregularities in the form of triangular elements, the period of triangular elements is chosen from the condition for the formation of the Bragg bandgap in the range of wave numbers from 100 cmup to 300 cm, a piezoelectric element having a length less than the length of the magnetic element, solid-made outer electrode of the piezoelectric element, and the electrode adjacent to the surface of the magnetic element is in the form of an interdigital transducer with a period T selected from the condition T=2P, where P is the period of the triangular elements.EFFECT: creation of a frequency filter of the UHF signal with control of the frequency range of the filter and the bandwidth, the reduction of the sizes to the micro-dimensional domain, and simplification of the design.6 cl, 5 dwg

Design and fabrication of zero-group-velocity Lamb wave resonator onto silicon nitride/aluminum nitride suspended membrane

Abstract: The propagation of the Lamb-like modes along an AlN/Si3N4 thin suspended membrane was simulated in order to exploit the zero group velocity (ZGV) resonant conditions, ie the frequencies where the mode group velocity vanishes while the phase velocity remains finite A ZGV micro electroacoustic resonator employing only one interdigital transducer (IDT) and no reflectors was designed that is based on the propagation of the first quasi symmetric mode qS1 at frequency of about 163 GHz The device was fabricated directly onto commercially available thin suspended Si3N4 membrane, 200 nm thick, in square silicon supporting frame (200 μm thick) The Cr/Au interdigital transducer (IDT), with periodicity of 10 μm, was fabricated by electron beam lithography (EBL) directly onto the Si3N4 membrane; then the piezoelectric AlN layer was grown onto the membrane at room temperature by rf reactive magnetron sputtering technique The technological feasibility of the ZGV resonator on commercial Si3N4 suspended membrane is demonstrated and preliminary experimental results are shown

Influence of electrode width of interdigital transducer on third-order nonlinearity of surface acoustic wave devices on 42°YX-LiTaO3 substrate

Abstract: In this paper, we discuss the influence of the electrode width of an interdigital transducer on the third-order nonlinearity of surface acoustic wave (SAW) devices. First, an estimation technique of third-order nonlinear signals based on the linear finite element method is proposed, and the variation of nonlinear signal level with electrode width is estimated. Then, several one-port SAW resonators with different electrode widths are fabricated, and measured nonlinear signal levels are compared with simulation. As predicted by the numerical simulation, nonlinear signal levels became large with electrode width. However, harmonics takes a minimum at a certain electrode width. This tendency disagrees with the simulation. The variation of nonlinear coefficients is evaluated by numerical fitting for the measured data using the nonlinear signal simulator proposed by the authors. As the result, it is concluded that the generation mechanism is not limited to the acoustic strain in electrodes.

Frequency response study of surface acoustic wave devices with SiO x N y film using LiTaO3 substrate

Abstract: In an attempt to suppress the frequency variation of a surface acoustic wave device caused by dielectric film deposition on an interdigital transducer (IDT) electrode, we fabricated a one-port resonator and examined the correlation with frequency response and refractive index when a SiO x N y film is deposited. Our data showed that the resonator frequency changes as the refractive index of the SiO x N y film changes. We also found that the frequency drift caused by the SiO x N y deposition can be suppressed if the refractive index is kept in a certain range. Then, we performed a finite element method spectral domain analysis to calculate frequency response using the Young's modulus obtained in this experiment. The calculated frequency response indicated that the refractive index of the SiO x N y film needs to be altered in accordance with the IDT electrode thickness. We suggest that one of the effective ways of controlling the frequency response is to manage the refractive index of SiO x N y .

Standing surface acoustic wave technology applied for micro-particle concentration in oil

Abstract: Oil lubrication plays an important role in a variety of mechanical equipment. The traditional purification method is difficult to remove the tiny impurity size of 5-15 μm. Three different types of the transducers and its preparation methods were used in the experiment. The phenomenon that the impurity particles in viscous fluid by the acoustic radiation force was moved the wave node position and focused on the center line was observed by the super-depth microscope. The influence factors of the produced SSAW, particle force condition and movement track were analyzed. The experimental results show that the interdigital transducer can be used to generate SSAW, so as to achieve the separation effect of oil and suspended particles.

Surface acoustic wave filter, packaging method and electronic equipment thereof

Abstract: A surface acoustic wave filter and its packaging method and electronic device are provided, a surface acoustic wave filter is provided with a device wafer and a cap plate, a signal pattern and a device are respectively formed on the device wafer and the cap plate, a through hole and a bonding pad are arranged on the cap plate, the device wafer and the cap plate are boned, the interdigital transducer is accommodated in the closed cavity, and the first signal pattern is electrically connected with the bonding pad through the through hole, so that the signal can be transmitted without the need ofseparately arranging wires, and compared with other packaging technologies, the device wafer and the bonding pad are simple in structure and small in package size.

Coexisting Surface and Bulk Gyroscopic Effects

Abstract: We report coexisting surface and bulk gyroscopic effects in the same structure. The surface acoustic wave (SAW) and bulk acoustic wave (BAW) is driven and sensed by interdigital transducer (IDT) on a lithium niobite substrate. The gyroscope is tested on a dither stage which is integrated with a pc board. The stage can apply angular rate as high as 8000 deg/s in air. The IDT drive RF frequency is swept while mechanical dithering the stage. The outputs from both sense ports are demodulated at RF frequency, followed by demodulation at the stage angular dither frequency. The device shows gyroscopic effect when driving not only at the resonance frequency of the SAW, but also at the resonance frequency of BAW modes. The measured scale factor for SAW mode and a bulk mode was 29 nV/(deg/s) and 137 nV/(deg/s), respectively. The peaks in the second demodulation versus frequency occur at spacing of ~7.2 MHz, with Q≈ 30,000. COMSOL simulation predicts bulk mode frequency starts at 3.75 MHz, with spacing of 7.5 MHz. The bulk mode can be suppressed by integrating acoustic absorber to the gyroscope. The bulk waves in the thickness mode are established between the top and bottom of wafer, while the SAW waves are excited by the top and IDT electrodes.

Acoustic surface wave liquid guide device

Abstract: The invention discloses an acoustic surface wave liquid guide device which comprises a pieozelectric substrate (1), a first interdigital transducer (51), a liquid storage bin (6) and a micro runner (8). The liquid storage bin (6) and the micro runner (8) are closely fitted on the surface of the pieozelectric substrate (1), and the first interdigital transducer (51) and the micro runner (8) are arranged on two sides of the liquid storage bin (6) which is communicated with the micro runner (8). The acoustic surface wave liquid guide device can ensure continuous and stable pumping and timely andsufficient atomizing of tobacco liquid, the technical defect of passive liquid guide is overcome, and empty drying is avoided, so that smoking quality is improved, and user experience is improved.

Elastic wave device, high-frequency front end circuit, and communication device

Abstract: An acoustic wave device includes a supporting substrate, an acoustic reflection film the supporting substrate, a piezoelectric thin film on the acoustic reflection film, and an interdigital transducer electrode the piezoelectric thin film. The acoustic reflection film includes acoustic impedance layers including therein first, second, third, and fourth low acoustic impedance layers and first, second, and third high acoustic impedance layers. The acoustic reflection film includes a first acoustic impedance layer and a second acoustic impedance layer, the first and second acoustic impedance layers each being one of the acoustic impedance layers, and the second acoustic impedance layer has an arithmetic average roughness different from that of the first acoustic impedance layer.

Surface acoustic wave resonant transducer

Abstract: The utility model relates to a surface acoustic wave resonant transducer, including piezoelectric substrate, interdigital transducer, two sets of slot reflecting grating array and the antenna of setting on the piezoelectric substrate, wherein interdigital transducer's electrode is extremely external antenna, two sets of slot reflecting grating arrays symmetries set up in interdigital transducer'sboth sides, and slot reflecting grating array includes many parallel arrangement's slot reflecting grating, the length imbalance of many slot reflecting gratings, and wherein the length change of slotreflecting grating accords with the weighting function equation. Foretell surface acoustic wave resonant transducer adopts the slot reflecting grating, because the reflectivity of slot reflecting grating is bigger, can effectively reduce the reflecting grating figure to sensor size has significantly reduced. In addition, the length imbalance of slot reflecting grating adopts the weighted mode oflength can effectively restrain the secondary lobe height of sensor for the sensor interference killing feature is strong.

Saw filter that comprises piezoelectric substrate having stepwise cross section

Abstract: PROBLEM TO BE SOLVED: To provide a surface acoustic wave (SAW) filter with improved performance.SOLUTION: A surface acoustic wave filter 100 comprises: a supporting substrate 120 including a first structure layer; and a piezoelectric substrate 110 arranged on and mechanically supported by the supporting substrate. The piezoelectric substrate 110 includes: a piezoelectric substrate that includes a first region having a first thickness and a second region having a second thickness different from the first thickness; and a plurality of interdigital transducer (IDT) electrodes arranged on the piezoelectric substrate. A first IDT electrode 131 is arranged in the first region of the piezoelectric substrate, and includes a first IDT electrode finger that has a first pitch L. A second IDT electrode 132 is arranged in the second region of the piezoelectric substrate, and includes a second IDT electrode finger that has a second pitch Ldifferent from the first pitch.SELECTED DRAWING: Figure 1

Surface acoustic wave high temperature strain sensor chip and application structure based on sheet metal and piezoelectric membrane

Abstract: The utility model provides a surface acoustic wave high temperature strain sensor chip and application structure based on SOI and piezoelectric membrane, this high temperature strain sensor chip includes the basement of SOI chip, the basement of SOI chip has first surface and second surface, be formed with the piezoelectric membrane in the basement of SOI chip, be formed with interdigital transducer and reflecting grating on the piezoelectric membrane, be formed with insulation protective layer on interdigital transducer and reflecting grating, there is the through -hole to be connected to bottom electrode and interdigital transducer respectively on piezoelectric membrane and insulation protective layer, through -hole department on insulation protective layer is formed with the signal anddraws forth the dish, and have or does not have following structure: extend to the SOI isolation layer from SOI chip basement bottom surface and be formed with the cavity of meeting an emergency in the basement of SOI chip, the cavity all has the opening in SOI chip basement bottom surface and SOI chip basement lateral wall. This high temperature strain sensor chip simple structure, small, light in weight, precision are high, can be applied to the measurement of answering the variable element under the high temperature environment such as aerospace, petrochemical, nuclear industry.

Surface acoustic wave through special infiltration nature optimization selects separately chip

Abstract: The utility model discloses a surface acoustic wave through special infiltration nature optimization selects separately chip The partial characteristic that the optimization of infiltration nature, wide band / frequency conversion interdigital transducer technique, water conservancy were selected separately to this chip fuses with surface acoustic wave sorting method mutually, realizes pair cell/ particle high flux enrichment, specific cell / particle high -purity and selects separately The chip during operation, the surface acoustic wave that interdigital transducer produced says to the miniflow that interior fluid and cell / particle impose the effect of sound field and acoustic radiation power In addition, adopt special infiltration nature optimization processing because of the basement of selecting separately the runner, will have differences such as surface tension, grab, shearing force and wall slide in the different infiltration nature microdomain territory interfaces Whenthe region is selected separately to the cell process of arranging into the team, the cell will deviate its primary flow line tracking under acoustic streaming effect, acoustic radiation power, viscous force effects such as ( stokes power), and under the coupling of special infiltration nature optimization basement, the migration velocity of cell / particle and distance increase have improved sorting flux and efficiency

Surface acoustic wave non-contact atomization device

Abstract: The invention discloses a surface acoustic wave non-contact atomization device. The surface acoustic wave non-contact atomization device comprises a piezoelectric substrate (1), T-shaped fiber paper (10), a second interdigital transducer (52) and a third interdigital transducer (53), wherein the second interdigital transducer (52) and the third interdigital transducer (53) are placed on the two sides of the T-shaped fiber paper (10), and the T-shaped fiber paper (10), the second interdigital transducer (52) and the third interdigital transducer (53) closely fit the surface of the piezoelectricsubstrate (1). The surface acoustic wave non-contact atomization device has a strong E-liquid atomization capability and can generate a large amount of smoke per unit time, and a user can quickly obtain a sense of satisfaction in smoking.

Piston mode lamb wave resonators

Abstract: Piston mode Lamb wave resonators are disclosed. A piston mode Lamb wave resonator can include a piezoelectric layer, such as an aluminum nitride layer, and an interdigital transducer on the piezoelectric layer. The piston mode Lamb wave resonator has an active region and a border region, in which the border region has a velocity with a lower magnitude than a velocity of the active region. The border region can suppress a transverse mode.

A paper-based microfluidic device with cotton thread channels based on surface acoustic wave

Abstract: A new paper-based microfluidic device is fabricated on a piezoelectric substrate. A polydimethylsiloxane channel filled with cotton threads is mounted on the piezoelectric substrate with an interdigital transducer. A testing filter paper with dried reaction solution is coated on the end of the cotton thread. Sample solution is driven to the cotton thread channel and transported to testing area for microfluidic analysis. Red ink solution and color development reaction of starch are demonstrated for microfluidic operation and analysis. Results show that the linear velocity of microfluidic transportation in the cotton thread channel is 4.558 mm/s, and color development reaction of starch is successfully implemented.

Surface acoustic wave temperature and humidity sensor

Abstract: The invention relates to a surface acoustic wave temperature and humidity sensor, belongs to the field of temperature and humidity testing, and solves the problem that an existing sensor cannot simultaneously measure temperature and humidity, or cannot differentiate the signals of multiple sensors. The surface acoustic wave temperature and humidity sensor mutually converts a surface acoustic waveand an electromagnetic wave by an interdigital transducer disposed on a delay line, and calculates the temperature and the humidity by a spread time difference of the surface acoustic wave on the delay line. The surface acoustic wave temperature and humidity sensor measures the temperature and humidity information wirelessly, and reduces the later maintenance of complicated wires. The surface acoustic wave temperature and humidity sensor is a passive device, has a service life not limited by a battery, and is suitable for extreme conditions such as airtightness and high-speed rotation. The surface acoustic wave temperature and humidity sensor integrates coding information and can conveniently obtain the correspondence between monitoring points and monitoring information.