Showing papers on "Interdigital transducer published in 2006"

Surface acoustic wave trapping in a periodic array of mechanical resonators

Abstract: The existence of two families of surface acoustic modes trapped by steep ridges on a piezoelectric substrate, shear horizontal and vertically polarized surface modes, is demonstrated experimentally using high aspect ratio interdigital transducers fabricated on lithium niobate. The experimental variation of the resonance frequencies of the various surface modes is obtained experimentally, and up to an order of magnitude slowing of surface waves is observed, with the phase velocity dropping from 4000 down to 450m∕s. It is argued that the observed resonances are surface modes trapped by the ridge electrodes.

Disposable and trimmable wireless pressure sensor

Abstract: A disposable pressure sensor includes a substrate and a pressure diaphragm formed upon the substrate (101). A sensor coil can be provided, comprising a capacitor (110) and an inductor (104) formed on the substrate and surrounded by the pressure diaphragm (112). The ferrite core (106) is located proximate to the sensor coil, such that when the pressure diaphragm (112) is exposed to a pressure, the diaphragm (112) moves close to the inductor (104) or the capacitor (110), thereby resulting in a change in the capacitor (110) or the inductor (104) and an indication of pressure. The capacitor can be implanted as an adjustable, trimmable or variable capacitor. The inductor may also be provided as an adjustable or variable inductor and can include the use of a variable capacitor and a PVDF based piezoelectric transducer. When the PVDF layer is under pressure, it can generate an electric field across the interdigital transducer and transmit a signal thereof through an antenna.

Layer acoustic wave device and method of making the same

Abstract: The present invention provides a layer acoustic wave device that is formed without requiring a bonding process to attach a secondary substrate. In particular, the layer acoustic wave device is formed from a substrate, an interdigital transducer created on the substrate, a dielectric layer formed over the interdigital transducer and substrate, and at least one isolation layer formed over the dielectric layer. The at least one isolation layer has sufficient properties to minimize particle displacement on a top surface of the at least one isolation layer. The at least one isolation layer has a greater acoustic impedance than that of the dielectric layer.

Surface acoustic wave two-dimensional transport and location of microdroplets using echo signal

Abstract: Digitalized microfluidics is dealing with microdroplet actuation and location. We propose the implementation of a surface acoustic wave (SAW) echo method so as to move and to locate a microdroplet from a single interdigital transducer (IDT). A prototype working at 20MHz demonstrates the ability of this method to achieve the goal with submillimeter accuracy quite sufficient for aimed biologic applications. The tested platform fitted with one IDT built on a LiNbO3 substrate allows the tracking of water droplets actuated by SAW running free or squeezed under a cover for biological treatments in a lab on chip.

Surface acoustic wave apparatus

Abstract: A surface acoustic wave apparatus has a configuration by which the spurious of the higher-order transverse modes is suppressed and a SAW excitation intensity distribution is not changed in the propagation direction The surface acoustic wave apparatus has at least one interdigital transducer; a region with the plurality of interleaved comb-shaped electrodes is formed with two regions which are a first overlapping region and a second overlapping region with overlapping-lengths weighted along a propagation direction of a surface acoustic wave; the first overlapping region and the second overlapping region are in contact or overlapped in a direction vertical to the propagation direction of the surface acoustic wave; and in either the first or the second overlapping region, an overlapping-length weighting envelope curve has at least two or more changing points in the propagation direction of the surface acoustic wave

Lamb wave type high frequency device

Abstract: A lamb wave type high frequency device includes: an interdigital transducer (IDT) electrode having an electrode finger interdigitated therein; a pair of reflectors having an electrode finger and being disposed at both sides of a propagation direction of a lamb wave excited by the IDT electrode; and a piezoelectric substrate on a surface of which the IDT electrode and the reflectors are disposed, wherein a pitch of the electrode finger of the IDT electrode and a pitch of the electrode finger of the reflectors are different from one another.

High-temperature 434 MHz surface acoustic wave devices based on GaPO/sub 4/

Abstract: Research into surface acoustic wave (SAW) devices began in the early 1970s and led to the development of high performance, small size, and high reproducibility devices. Much research has now been done on the application of such devices to consumer electronics, process monitoring, and communication systems. The use of novel materials, such as gallium phosphate (GaPO4), extends the operating temperature of the elements. SAW devices based on this material operating at 434 MHz and up 800degC, can be used for passive wireless sensor applications. Interdigital transducer (IDT) devices with platinum/zirconium metallization and 1.4 mum finger-gap ratio of 1:1 have been fabricated using direct write e-beam lithography and a lift-off process. The performance and long-term stability of these devices has been studied, and the results are reported in this paper

Elastic wave device and filter

Abstract: PROBLEM TO BE SOLVED: To provide an elastic wave device and filter in which a Q value of a capacitance composed of an electrode facing a piezoelectric substrate horizontally is large in a high frequency band. SOLUTION: The elastic wave device includes: a piezoelectric substrate (16); a resonator (13) composed of an interdigital electrode (12) and a reflection electrode (R1) provided on the piezoelectric substrate (16) to excite an elastic wave, and an interdigital electrode type capacitance (14) provided over the piezoelectric substrate (16), connected to the resonator (13) in parallel or in series and facing the piezoelectric substrate (16) horizontally, wherein an interdigital electrode constituting the interdigital electrode type capacitance (14) is provided more separately from the piezoelectric substrate (16) than the interdigital electrode (12) constituting the resonator (13). COPYRIGHT: (C)2008,JPO&INPIT

Filter and demultiplexer

Abstract: PROBLEM TO BE SOLVED: To provide a filter and a demultiplexer capable of reducing ripple produced in a pass band. SOLUTION: The filter and the demultiplexer includes a plurality of piezoelectric thin film resonators each consisting of a substrate (10), a lower electrode (12) provided on the substrate, a piezoelectric film (14) provided on the lower electrode, and an upper electrode (16) provided on the piezoelectric film. At least one piezoelectric thin film resonator among the plurality of the piezoelectric thin film resonators is configured, in a way that a shape thereof at a portion where the lower electrode and the upper electrode face each other sandwiching the piezoelectric film therebetween is different, in view of spurious generation frequency from that of other piezoelectric thin film resonator. COPYRIGHT: (C)2008,JPO&INPIT

Method of forming a surface acoustic wave (SAW) filter device

Abstract: A SAW filter includes a piezoelectric substrate of Lithium Niobate or optionally Lithium Tantalate having a thickness of at least twice an acoustic wavelength. The piezoelectric substrate is bonded to a surrogate substrate of a silicon material. The surrogate substrate is characterized by a resisitivity of at least 100 ohm-cm and an expansion coefficient compatible with the piezoelectric substrate. A catalytic bonding film between the piezoelectric substrate and the surrogate substrate is formed from a first catalytic bonding film deposited onto a surface of the piezoelectric substrate and a second catalytic bonding film deposited onto a surface of the surrogate substrate. The piezoelectric substrate is bonded to the surrogate substrate through a compression force sufficient for providing a bonding at a normal temperature.

Temperature compensation for ball surface acoustic wave devices and sensor using frequency dispersion

Abstract: We propose a new temperature compensation method for ball surface acoustic wave (SAW) devices using frequency dispersion. This method distinguishes the temperature effect independent of frequency and surface effects such as mass loading or elastic effects linearly dependent on frequency. After stating the principle of the method, we verify it by fabricating ball SAW devices with an interdigital transducer (IDT) that works at two frequencies, and apply them to the measurement of the coating of albumin on the surface of the device and on a hydrogen gas sensor with a surface-coated sensing film. Delay time measurements are carried out at two frequencies, and the difference in delay time is calculated to eliminate temperature-independent effects. Because the results clearly show surface effects without temperature disturbance, it is a difficult to realize sensors using ball SAW devices.

A novel architecture of implementing wavelet transform and reconstruction processor with SAW device based on MSC

Abstract: We propose to implement wavelet transform and reconstruction processor with surface acoustic wave (SAW) device based on multistrip coupler (MSC). Uniform interdigital transducer (IDT) and reconstruction wavelet IDT were grated on two output tracks of wavelet IDT, respectively. This architecture enables wavelet transform and wavelet reconstruction operation to be simultaneously implemented in one processor. Furthermore, second insertion loss is overcome in wavelet reconstruction processor.

3F-3 Liquid Sensor Using SAW and SH-SAW on Quartz

Abstract: One-chip sensor system using two different acoustic waves on ST-cut quartz is presented; one is shear horizontal surface acoustic wave (SH-SAW) and the other is surface acoustic wave (SAW). On the sensor chip, there is a SH-SAW delay-line that is composed of a transmitting interdigital transducer (IDT), receiving IDT and a biochemical reaction area in between them. And there is another IDT on the sensor chip, that can excite a Rayleigh type SAW to the biochemical reaction area in the direction normal to the SH-SAW propagation direction. In order to evaluate the performance of the SH-SAW delay-line sensor, C-reactive protein antibodies with different concentrations are provided to the biochemical reaction area. The phase change in the S21 response of the SH-SAW delay-line at a fixed frequency are measured on real-time and it is confirmed that different phase changes are obtained for different antibody concentrations. On the other hand, the one-chip quartz-based liquid-phase SH-SAW delay-line sensors with pumping and agitating functions using SAW are demonstrated

Surface acoustic wave device and communication terminal using the same

Abstract: A surface acoustic wave device in the present invention is provided with a piezoelectric substrate, a supporting substrate being jointed to the piezoelectric substrate and including a material different in expansion coefficient from the piezoelectric substrate and an interdigital electrode for exciting a surface acoustic wave, the electrode being arranged on the surface of the piezoelectric substrate. Either the interdigital electrode or the piezoelectric substrate is configured so that the interdigital electrode is 40% or more to 70% or less as long as the piezoelectric substrate in the direction to which a surface acoustic wave propagates.

Atomizing apparatus and suction device

Abstract: PROBLEM TO BE SOLVED: To provide a simply structured atomizing apparatus capable of efficiency atomizing a liquid SOLUTION: The atomizing apparatus 10 is provided with an atomizer 40 and a liquid leading passage 81 communicating a reservoir 20 and the space 80 with each other to supply the liquid to the propagation zone of the surface acoustic wave by a capillary phenomenon and formed on the liquid supply plate 70 The atomizer 40 comprises a reservoir 20 for housing the liquid, a surface acoustic wave device 50 obtained by forming an interdigital transducer (IDT) electrode 52 on the main surface of a piezoelectric substrate 51, a high frequency generation circuit part connected to IDT electrode 52 and for generating surface acoustic wave and a liquid supply plate 70 fixed to the surface acoustic wave device 50 to form a space 80 with the surface acoustic wave device 50 in the thickness direction of the propagation zone of the surface acoustic wave COPYRIGHT: (C)2008,JPO&INPIT

Balanced acoustic wave filter

Abstract: In an acoustic wave filter device, first and second surface acoustic wave filter sections implemented by longitudinally coupled resonators are arranged on a piezoelectric substrate. The first and second surface acoustic wave filter sections include first to third interdigital transducers and fourth to sixth interdigital transducers, respectively, arranged in a direction of propagation of surface waves. The first, third, fourth, and sixth interdigital transducers are connected to an unbalanced terminal. The second and fifth interdigital transducers are connected to first and second balanced terminals, respectively. Each of the second and fifth interdigital transducers has first and second interdigital transducer segments divided in the direction of propagation of acoustic waves. The first and second interdigital transducer segments are connected in series with each other.

Surface acoustic wave device and fabrication method therefor

Abstract: A surface acoustic wave device includes a piezoelectric substrate, a surface acoustic wave element composed of electrodes provided on the piezoelectric substrate and the piezoelectric substrate, a first seal resin portion provided on the piezoelectric substrate and having a cavity on the surface acoustic wave element, and an inorganic insulation film provided in contact with a surface of the piezoelectric substrate to surround the surface acoustic wave element.

Saw filter comprising a broadband band-stop filter

Abstract: A band-stop filter is described herein. The band-stop filter includes a piezoelectric substrate and a plurality of surface wave element (SAW) impedance elements on the substrate. The band-stop filter also includes at least one series branch comprising at least one series resonator having a finger period, and a plurality of parallel branches connected electrically in parallel with the series branch, each parallel branch including at least one parallel impedance element comprising an interdigital transducer and having a finger period. The average finger period of the at least one series resonator is greater than the average finger period of the at least one parallel impedance element.

Elastic band gaps for surface modes in an ultrasonic lithium niobate phononic crystal

Abstract: If a number of experiments aiming at demonstrating fundamental properties of phononic crystals have been successfully implemented, a need for enlarging both the research and the application fields of these structures has more recently risen. Surface acoustic waves appear as appealing candidates to set a new ground for illustrative experiments involving some different physical concepts from those usually observed when dealing with bulk waves. The possibility of a direct excitation of these surface waves on a piezoelectric material, and their already extensive use in ultrasonics also make them an interesting basis for phononic crystal based, acoustic signal processing devices. In this work, wave propagation in a square lattice, piezoelectric phononic crystal consisting of air holes etched in a lithium niobate matrix is both theoretically and experimentally investigated. The crystal was fabricated by reactive ion etching of a bulk lithium niobate substrate. Standard interdigital transducers were used to characterize the phononic structure by direct electrical generation and detection of surface waves. A full band gap around 200 MHz was experimentally demonstrated, and close agreement is found with theoretical predictions.

Leaky SAW resonator and method

Abstract: A SAW ladder filter includes grating pads extending from opposing bus bars and interdigital transducer electrodes extending from the grating pads for defining an acoustic aperture. The metalization ratio for the grating pads is greater than that for the interdigital transducer electrodes. Reflector electrodes are disposed on opposing longitudinal sides of the interdigital transducer electrodes. Operation of the filter results in a velocity of the SAW along the grating pads slower than a SAW velocity along the plurality of interdigital transducer electrodes, thus producing a wave guiding effect for optimizing SAW propagation within the acoustic aperture. The grating pads may be longitudinally offset from cooperating interdigital transducer electrodes using minor bus bars.

Surface acoustic wave device and method of manufacturing the same

Abstract: First base layers made of TiN or TiO x N y (where, 0

Acoustic surface wave atomizer

Abstract: In a surface acoustic wave atomizer, a balance between a liquid supply amount and an atomization amount is maintained, and a large amount of fine particles can be stably sprayed with less power consumption. A surface acoustic wave atomization apparatus (1) includes a vibrator (2) in which a pair of comb electrodes (21) is formed, and a surface acoustic wave is generated by applying a high frequency voltage to the comb electrodes (21). Liquid supply means 3 for supplying a liquid to the surface S, and the liquid supplied to the surface S of the vibrator 2 by the liquid supply means 3 is atomized by the surface acoustic wave w generated on the surface S. The liquid supply means 3 includes a liquid film forming member 30 that forms a film formation gap G for distributing the supply liquid on the surface of the vibrator 2 in a film shape, and the shape of the film formation gap G has the shape of the vibrator 2. The length b in the traveling direction x of the surface acoustic wave w is shorter than the length a in the width direction y perpendicular to the traveling direction x of the surface acoustic wave w generated on the surface S of the surface S. [Selection] Figure 1

Acoustomagnetic pulse experiments in LiNbO3∕Mn12 hybrids

Abstract: We report here on the influence of surface acoustic waves (SAWs) on the magnetization of a Mn12-acetate single crystal The crystal was mounted on the surface of a piezoelectric LiNbO3 substrate containing an interdigital transducer for the excitation of SAWs The magnetization of the crystal was measured using a rf superconducting quantum interference device with a time resolution of 1μs The piezoelectric material was excited by SAW pulses of different frequencies produced by applying microwave pulses to the transducer Our data show that molecular magnets onto the LiNbO3 surface can be used as very sensitive detectors of the SAW frequency and intensity

Field analysis and calculation of interdigital transducers with arbitrary finger shapes

Abstract: The interdigital transducer (IDT) is a key component in surface-acoustic wave (SAW) and acousto-optical devices and has extensive applications in signal processing and optical communication at present. Properties of the acoustic field are mainly dominated by the geometric shapes of the electrodes (i.e. fingers) of the IDT and the piezoelectric characteristics of the substrate. However, the studies on excitation and acoustic wave field characteristics of IDTs are still not matured or perfect. In this paper, the 2D interface Green's function method (GFM) for simulating numerically the SAW field of IDTs with arbitrary finger shapes is presented. The electric charge densities originated from the electrostatic field and the generated SAW on the IDT electrodes are calculated first using the 2D interface GFM. Then the charge density distribution as the distributed source of SAW used to calculate the SAW field. IDT with arbitrary finger shapes can be treated. As an example, the properties of a SAW field generated by focused IDTs with the shape of concentric circular arc fingers on Y–Z LiNbO3 and c-oriented PZT substrates are also analysed and discussed. The method can be applied to numerical analysis of IDTs with arbitrary finger shapes, such as broadband chirp transducers, curved-finger transducers and finger-length weighted transducers.

High-Coupling and High-Temperature Stable Surface Acoustic Wave Substrates Using Groove-Type Interdigital Transducer

Abstract: In this study, to obtain new substrates with the high coupling of electromechanical coefficients (k2) and near-zero temperature coefficients of frequency (TCFs), very thin periodic grooves and interdigital transducers (IDTs) are fabricated on high-coupling substrates. Simulation results show a high k2 (over 0.4) at H/λ=0.1 for rotated Y-cut, X-propagating LiNbO3 leaky surface acoustic wave substrates, and a high k2 (over 0.08) and a small TCF (-10 ppm/°C) at H/λ=0.1 for 36°Y-cut, X-propagating LiTaO3 leaky surface acoustic wave (SAW) substrates. The experimental results showed good agreements with the theoretical results.

Piezoelectric laminate, manufacturing method of same, surface acoustic wave element, thin film piezoelectric resonator, and piezoelectric actuator

Abstract: PROBLEM TO BE SOLVED: To provide a piezoelectric laminate including a potassium sodium niobate layer formed on a substrate SOLUTION: The piezoelectric laminate 100 comprises a substrate 1; a template layer 3a formed above the substrate 1; and a piezoelectric layer 3b consisted of potassium sodium niobate and formed above the template layer 3a COPYRIGHT: (C)2008,JPO&INPIT

P3O-4 SiO2/Grooved Al-Electrodes/LiTaO3 Structures Having Large Reflection Coefficient, Large Coupling Factor, and Excellent Temperature Characteristics Even with Thick Al Electrode

Abstract: A surface acoustic wave (SAW) substrate for a duplexer such as Personal Communication Service handy phone system in US is required to have a good temperature coefficient of frequency (TCF), an optimum electromechanical coupling factor, and a large reflection coefficient. However, there have been no SAW substrates satisfying all of them. Because the duplexer is composed of resonator-type devices such as a ladder filter or a multimode resonator filter, thick Al electrodes for interdigital transducer (IDT) and grating reflectors on a substrate are used in order to achieve the large reflection coefficient. The TCF of the SAW substrate such as LiTaO3 or LiNbO3 for a transversal SAW filter using a thin Al electrode is negative so that a SiO2 film having a positive TCF is often deposited on the substrate to improve the TCF. But, when a thick SiO2 film was deposited on a resonator and a longitudinally coupled multimode resonator filter composing of thick Al electrodes on 36degYmiddotX-LiTaO3 substrates to improve the TCF, their frequency characteristics remarkably deteriorated, because of large convex portions (as thick as Al electrodes) yielded on a surface of the SiO2 film and the small coupling factor decreased due to their convex portions. The authors have considered that thick SiO2 /grooved Al-electrodes/LiTaO3 structures SAW substrate would have an excellent TCF, a large reflection coefficient, and an optimum coupling factor even if using thick Al electrodes. The results of the experiment and the calculation clarified that resonators consisting of the newly developed SAW structure had good frequency characteristics, the large reflection coefficient, the optimum coupling coefficient, and the excellent TCF (-3ppm/degC)

Elastic surface wave device

Abstract: A surface acoustic wave device includes a pair of reflectors and an interdigital transducer having a cross electrode having a interdigitated portion and a dummy portion and a dummy electrode. The dummy electrode has a length different from the length of the dummy portion of the cross electrode arranged adjacent to the dummy electrode.

Liquid Sensor Using SAW and SH-SAW on Quartz

Abstract: One-chip sensor system using two different acoustic waves on ST-cut quartz is presented; one is shear horizontal surface acoustic wave (SH-SAW) and the other is surface acoustic wave (SAW). On the sensor chip, there is a SH-SAW delay-line that is composed of a transmitting interdigital transducer (IDT), receiving IDT and a biochemical reaction area in between them. And there is another IDT on the sensor chip, that can excite a Rayleigh type SAW to the biochemical reaction area in the direction normal to the SH-SAW propagation direction. In order to evaluate the performance of the SH-SAW delay-line sensor, C-reactive protein antibodies with different concentrations are provided to the biochemical reaction area. The phase change in the S21 response of the SH-SAW delay-line at a fixed frequency are measured on real-time and it is confirmed that different phase changes are obtained for different antibody concentrations. On the other hand, the one-chip quartz- based liquid-phase SH-SAW delay-line sensors with pumping and agitating functions using SAW are demonstrated.

Wireless and passive acoustic wave liquid conductivity sensor

Abstract: A method and system for measuring liquid conductivity utilizing an acoustic wave sensor. In general, an acoustic wave device can be provided with one or more interdigital transducers, including at least a first interdigital transducer and at least a second interdigital transducer having a cavity formed therebetween, wherein liquid comes into contact with the cavity. For example, a liquid, such as oil, may flow through the cavity. A measurement of the resistance and/or frequency of the acoustic wave device next to the cavity can be performed in order to obtain data indicative of the conductivity of the liquid.