Showing papers on "Interdigital transducer published in 2011"

Development of SAW-based multi-gas sensor for simultaneous detection of CO2 and NO2

Abstract: A 440 MHz wireless and passive surface acoustic wave (SAW)-based multi-gas sensor integrated with a temperature sensor was developed on a 41° YX LiNbO3 piezoelectric substrate for the simultaneous detection of CO2, NO2, and temperature. The developed sensor was composed of a SAW reflective delay lines structured by an interdigital transducer (IDT), ten reflectors, a CO2 sensitive film (Teflon AF 2400), and a NO2 sensitive film (indium tin oxide). Teflon AF 2400 was used for the CO2 sensitive film because it provides a high CO2 solubility, with good permeability and selectivity. For the NO2 sensitive film, indium tin oxide (ITO) was used. Coupling of mode (COM) modeling was conducted to determine the optimal device parameters prior to fabrication. Using the parameters determined by the simulation results, the device was fabricated and then wirelessly measured using a network analyzer. The measured reflective coefficient S11 in the time domain showed high signal/noise (S/N) ratio, small signal attenuation, and few spurious peaks. The time positions of the reflection peaks were well matched with the predicted values from the simulation. High sensitivity and selectivity were observed at each target gas testing. The obtained sensitivity was 2.12°/ppm for CO2 and 51.5°/ppm for NO2, respectively. With the integrated temperature sensor, temperature compensation was also performed during gas sensitivity evaluation process.

Planar coupling to high-Q lithium niobate disk resonators

Abstract: We demonstrate optical coupling to high-Q lithium niobate disks from an integrated lithium niobate waveguide. The waveguides are made by proton exchange in X-cut lithium niobate substrate. The disks with diameter of 4.7 mm and thickness of 1 mm are made from commercial Z-cut lithium niobate wafers by polishing the edges into a spheroidal profile. Both resonance linewidth and cavity ringdown measurements were performed to calculate the Q factor of the resonator, which is in excess of 10(8). Planar coupling represents the most promising technique for practical applications of whispering gallery mode resonators.

Acoustic wave guide device and method for minimizing trimming effects and piston mode instabilities

Abstract: An acoustic wave device operable as a piston mode wave guide includes electrodes forming an interdigital transducer on a surface of the piezoelectric substrate, wherein each of the plurality of electrodes is defined as having a transversely extending center region and transversely opposing edge regions for guiding an acoustic wave longitudinally through the transducer. A Silicon Oxide overcoat covers the transducer and a Silicon Nitride layer covers the Silicon Oxide overcoat within only the center and edge regions. The thickness of the Silicon Nitride layer is sufficient for providing a frequency modification to the acoustic wave within the center region and is optimized with a positioning of a Titanium strip within each of the opposing edge regions. The Titanium strip reduces the acoustic wave velocity within the edge regions with the velocity in the edge regions being less than the wave velocity within the transducer center region.

Experimental Investigation of a Cavity-Mode Resonator Using a Micromachined Two-Dimensional Silicon Phononic Crystal in a Square Lattice

Abstract: A 2-D silicon phononic crystal (PnC) slab of a square array of cylindrical air holes in a 10-μm-thick freestanding silicon plate with line defects is characterized as a cavity-mode PnC resonator. A piezoelectric aluminum nitride (AlN) film is employed as the interdigital transducers to transmit and detect acoustic waves, thus making the whole microfabrication process CMOS compatible. Both the band structure of the PnC and the transmission spectrum of the proposed PnC resonator are analyzed and optimized using finite-element method. The measured quality factor (Q factor) of the microfabricated PnC resonator is over 1000 at its resonant frequency of 152.46 MHz. The proposed PnC resonator shows promising acoustic resonance characteristics for radio-frequency communications and sensing applications.

Dual-mode piezocomposite ultrasonic transducer

Abstract: A compact, high power, dual mode, emitting and receiving ultrasound transducer and method for applying ultrasonic energy within a living subject and for monitoring the effects it induces in tissue comprises a set of piezoelectric polymeric transducer elements and a set of piezoelectric ceramic elements, bonded together. The polymeric transducer elements have electrodes enabling their use for low power diagnostic imaging interrogation of the tissue and the ceramic transducer elements have electrodes enabling their use for high power therapy applications.

Development of interdigital transducer sensors for non-destructive characterization of thin films using high frequency Rayleigh waves.

Abstract: In this paper, Rayleigh waves were generated and studied over a broad frequency range (5–50 MHz) and from the dispersion phenomenon, two substrate on layer type-samples with thin layer thicknesses of 1 μm and 500 nm, respectively, were characterized. The originality in this paper is the use of surface acoustic wave interdigital transducers (IDT) to generate surface waves as well as the development of a measuring device enabling an accurate estimation of the phase velocity to be obtained, which is essential in order to characterize such thin layers. Considering the excitation frequencies (5–50 MHz) and therefore the widths necessary on the electrodes for these types of IDT sensors (20–200 μm), a lift-off procedure was chosen to deposit the electrodes on the lithium niobate (LiNbO3) piezoelectric substrates. The use of these IDT, first enabled problems of loss and attenuation linked to the high frequency of conventional sensors (wedge sensors) to be overcome and second to carry out quasi-monochromatic measu...

Surface acoustic wave device and surface acoustic wave oscillator

Abstract: A surface acoustic wave device, includes: an interdigital transducer serving as an electrode pattern to excite a Rayleigh surface acoustic wave, the interdigital transducer including a comb-tooth-shaped electrode having a plurality of electrode fingers; a piezoelectric substrate on which the interdigital transducer is formed, the piezoelectric substrate being made of a quartz substrate that is cut out at a cut angle represented by an Euler angle representation (φ, θ, ψ) of (0°, 95°≦θ≦155°, 33°≦|ψ|≦46°); electrode finger grooves formed between the electrode fingers of the comb-tooth-shaped electrode; and electrode finger bases being quartz portions sandwiched between the electrode finger grooves and having upper surfaces on which the electrode fingers are positioned. The surface acoustic wave device provides an excitation in an upper limit mode of a stop band of the surface acoustic wave.

An Electronic-Nose Sensor Node Based on a Polymer-Coated Surface Acoustic Wave Array for Wireless Sensor Network Applications

Abstract: This study developed an electronic-nose sensor node based on a polymer-coated surface acoustic wave (SAW) sensor array. The sensor node comprised an SAW sensor array, a frequency readout circuit, and an Octopus II wireless module. The sensor array was fabricated on a large K2 128° YX LiNbO3 sensing substrate. On the surface of this substrate, an interdigital transducer (IDT) was produced with a Cr/Au film as its metallic structure. A mixed-mode frequency readout application specific integrated circuit (ASIC) was fabricated using a TSMC 0.18 μm process. The ASIC output was connected to a wireless module to transmit sensor data to a base station for data storage and analysis. This sensor node is applicable for wireless sensor network (WSN) applications.

Experimental Studies of Quality Factor Deterioration in Shear-Horizontal-Type Surface Acoustic Wave Resonators Caused by Apodization of Interdigital Transducer

Abstract: We investigate how the apodization applied to interdigital transducers (IDTs) affects the quality factor Q at the antiresonance frequency of surface acoustic wave (SAW) resonators. First, we fabricated SAW resonators with different apodization patterns on a SiO2/Cu/0°YX-LiNbO3 structure, and showed that the Q factor become worse when the apodization becomes steeper and the IDT aperture is narrower. Next, it was shown by optical measurement that the Q degradation is mainly due to the radiation of SH waves from the resonator. The radiation consists of energy leakage as bulk waves, diffraction, and scattering of incident SAWs, and their strength strongly depends on the steepness of the apodization pattern.

Determination of mass density, dielectric, elastic, and piezoelectric constants of bulk GaN crystal

Abstract: Mass density, dielectric, elastic, and piezoelectric constants of bulk GaN crystal were determined. Mass density was obtained from the measured ratio of mass to volume of a cuboid. The dielectric constants were determined from the measured capacitances of an interdigital transducer (IDT) deposited on a Z-cut plate and from a parallel plate capacitor fabricated from this plate. The elastic and piezoelectric constants were determined by comparing the measured and calculated SAW velocities and electromechanical coupling coefficients on the Z- and X-cut plates. The following new constants were obtained: mass density p = 5986 kg/m3; relative dielectric constants (at constant strain S) e11S/e0 = 8.6 and e11S/e0 = 10.5, where e0 is a dielectric constant of free space; elastic constants (at constant electric field E) C11E = 349.7, C12E = 128.1, C13E = 129.4, C33E = 430.3, and C44E = 96.5 GPa; and piezoelectric constants e33 = 0.84, e31 = -0.47, and e15 = -0.41 C/m2.

Transducer structure for a transducer probe and methods of fabricating same

Abstract: A composite ceramic transducer structure for use in the construction of an ultrasound probe includes a substrate and a plurality of piezoelectric transducer posts. The plurality of piezoelectric transducer posts are controllably formed on the substrate in a plurality of spatial positions located on an X-Y plane of the substrate. The plurality of piezoelectric posts includes a plurality of shapes defined in an X-Y-Z plane of the substrate, wherein the plurality of piezoelectric transducer posts are configured to facilitate minimizing shear waves within the ultrasound probe.

High-frequency surface acoustic wave filter based on diamond thin film

Abstract: This paper gives an overview of recent progress in developing diamond surface acoustic wave (SAW) devices for high-frequency applications. We have studied high-frequency SAW filters or resonators based on diamond thin films and demonstrated that diamond thin films have much potential for SAW applications above 3 GHz. Diamond film characteristics required for SAW filters in high-frequency applications are clarified. The results of numerical calculations reveal that the diamond-based SAW device, which employs a LiNbO3 thin film as the piezoelectric material, can provide a high electric coupling factor as well as a high phase velocity of more than 12 000 m/s. In contrast to when an AlN thin film is used as the piezoelectric material, the use of a SiO2/interdigital transducer/AlN/diamond structure enables the SAW device to have a low insertion loss for applications above 3 GHz.

Surface acoustic wave component

Abstract: A surface wave component contains at least two interdigital transducers having natural unidirectionality, disposed on a piezoelectric crystal substrate, which form a transducer pair consisting of transmission transducer and reception transducer. The transducers consist of an interdigital electrode structure having prongs and bus bars, and have opposite forward directions. At least two of the prongs form a transducer cell that has at least one excitation center for exciting an electrical potential wave and at least one reflection center for reflection of electrical potential waves, The transducer cells consist of two prongs having the same width, having a distance between the prong centers equal to half the length of a transducer period, whereby the electrode structures of the two transducers consist of the same material, but have different layer thicknesses.

Properties of shear horizontal acoustic plate modes in BT-Cut quartz

Abstract: Properties of shear horizontal acoustic plate modes (SHAPMs) in BT-cut quartz were calculated and measured. A delay line with a long interdigital transducer, deposited on -50.5°YX90°-oriented quartz plate, was used for the measurements. For one of the SHAPMs, at a frequency of about 100.4 MHz, insertion loss, turnover temperature, and quadratic temperature coefficient of frequency of about 10 dB, 15°C, and -30 ppb/(°C)2 in air, respectively, were obtained. Using water and glycerin solutions, insertion loss changes against dynamic viscosity were measured for this mode. In a viscosity range from about 1 mPa·s to 1000 mPa·s, an insertion loss change of about 14 dB was obtained.

Ultrasonic transducer assembly and system for monitoring structural integrity

Abstract: In an ultrasonic transducer assembly, a conformable ultrasonic transducer has a piezoelectric layer and electrodes able to conform to curved surfaces, and a clamp for pressing the transducer into ultrasonic contact with a curved surface. Conformability is ensured with a thin, porous piezoelectric layer and suitable electrical conductors and insulators. The ultrasonic transducer may operate without further thermal shielding under harsh environments and/or at high temperatures.

High-temperature (600 DEG C) pressure measurement passive wireless surface acoustic wave sensor

Abstract: The invention relates to a high-temperature (600 DEG C) pressure measurement passive wireless surface acoustic wave sensor. The passive wireless high-temperature pressure measurement sensor provided by the invention comprises a piezoelectric substrate material, an interdigital transducer, a reflecting grating, a small size antenna and a high-temperature lead, wherein a single-end surface acoustic wave resonator serves as the core of the high-temperature sensor; the lanthanum gallium silicate serves as the substrate; the interdigital transducer and the reflecting grating are deposited and arranged on the substrate; the surface acoustic wave is aroused and received by utilizing the piezoelectric effect and the inverse piezoelectric effect; the interdigital transducer receives an electromagnetic wave signal from a wireless inquiring unit through the antenna; the surface acoustic wave which is aroused from the surface of the substrate is spread towards two sides and is reflected by the reflecting grating; the reflected surface acoustic wave is reconverted to the electromagnetic wave signal through the interdigital transducer and is transmitted to the wireless inquiring unit through the antenna; and the pressure measurement at a high temperature is realized by using a signal processing method. The pressure sensor is provided with a pressure receiving diaphragm for sensing the pressure. The surface acoustic wave resonator is adhered to the pressure receiving diaphragm by using adhesives and is used for receiving the diaphragm deformation. The sensor has the advantages that the structure is simple, the volume is small, the weight is light, the precision is high, the sensor is wireless and passive, and the sensor is fit for the wireless remote monitoring for high-temperature environmental pressure in aerospace industry, petrochemical industry, nuclear industry, and the like.

Synchronous One-Pole Surface Acoustic Wave Resonator

Abstract: A surface acoustic wave resonator including an input interdigital transducer (IDT), an output IDT, and a pair of gratings with each being spaced from each other by a predetermined distance and attached to a substrate. In at least one embodiment, the distance is equal to one-half of the wavelength of the acoustic wave produced by the input IDT. In a further embodiment, the surface acoustic wave further includes a polymer layer and a biomedical coating covering at least a part of the polymer layer. The surface acoustic wave resonator has uses in the mass sensor and communications fields.

Multilayered Structure as a Novel Material for Surface Acoustic Wave Devices: Physical Insight

Abstract: Since 70-ies, when the first delay lines and filters employing surface acoustic waves (SAW) were designed and fabricated, the use of SAW devices in special and commercial applications has expanded rapidly and the range of their working parameters was extended significantly (Hashimoto, 2000; Ruppel, 2001, 2002). In the last decade, their wide application in communication systems, cellular phones and base stations, wireless temperature and gas sensors has placed new requirements to SAW devices, such as very high operating frequencies (up to 10 GHz), low insertion loss, about 1 dB, high power durability, stable parameters at high temperatures etc. The main element of a SAW device is a piezoelectric substrate with an interdigital transducer (IDT) used for generation and detection of SAW in the substrate. The number of single crystals utilized as substrates in SAW devices did not increase substantially since 70ies because a new material must satisfy the list of strict requirements to be applied in commercial SAW devices: sufficiently strong piezoelectric effect, low or moderate variation of SAW velocity with temperature, low cost of as-grown large size crystals for fabrication of 4-inch wafers, long-term power durability, well developed and non-expensive fabrication process for SAW devices etc. Today only few single crystals are utilized as substrates in SAW devices: lithium niobate, LiNbO3 (LN), lithium tantalate, LiTaO3 (LT), quartz, SiO2, lithium tetraborate, Li2B4O7 (LBO), langasite, La3Ga5SiO14 (LGS) and some crystals of LGS group (LGT, LGN etc.) with similar properties. The SAW velocities in these single crystals do not exceed 4000 m/s, which limit the highest operating frequencies of SAW devices by 2.5-3 GHz because of limitations imposed by the line-resolution technology of IDT fabrication. The minimum achievable insertion loss and maximum bandwidth of SAW devices depend on the electromechanical coupling coefficient, which can be evaluated for SAW as k2≈2ΔV/V, where ΔV is the difference between SAW velocities on free and electrically shorted surfaces. The largest values of k2 can be obtained in some orientations of LN and LT. Ferroelectric properties of these materials are responsible for a strong piezoelectric effect. As a result, k2 reaches 5.7% in LN and 1.2% in LT, for SAW. For leaky SAW (LSAW) propagating in rotated Y-cuts of both crystals, the coupling is higher and can exceed 20% for LN and 5% for LT. However, LSAW attenuates because of its leakage into the bulk waves when it propagates along the crystal surface. As a

Performance enhancement of a piezoelectric linear array transducer by half-concave geometric design

Abstract: A geometric design for array elements of a piezoelectric linear array transducer is proposed and evaluated. The design concept is based on the half-concave geometry, in which the radiating surface is concave while the other surface remains plane. A ∼1.8 MHz piezoelectric linear array transducer with half-concave elements has been designed, fabricated and evaluated. A dicing method was developed to shape the concave surfaces of the piezo elements and matching layers. By comparing the transducer performance, a traditional linear array transducer with similar dimension has been fabricated. It was found that the half-concave array transducer has significantly broader −6 dB bandwidth (96%), higher effective electromechanical coupling coefficient (0.62), and lower insertion loss (−21 dB) compared to those (76%, 0.55, and −25 dB, respectively) of the plane array transducer. The enhanced coupling coefficient and bandwidth are caused by the broaden resonance of the elements, which is induced by the continuously varying thickness in the designed geometry. The increased sensitivity is mainly attributed to the focused radiating surface.

Acoustic surface wave temperature sensing system used for buried cable

Abstract: The utility model belongs to the field of temperature measurement technology, and relates to an acoustic surface wave temperature sensing system used for a buried cable, comprising one or more signal reader-writer, a signal reader-writer comprises at least one acoustic surface wave temperature sensor located at the cable node, the acoustic surface wave temperature sensor is a passive type, and is connected with a built-in antenna, the signal reader-writer comprises a microprocessor, a radio-frequency signal emitting module, a radio-frequency receiving module, and a communication module respectively connected with the microprocessor, the microprocessor sends radio-frequency signals to the acoustic surface wave temperature sensor via the radio-frequency signal emitting module, an interdigital transducer of the acoustic surface wave temperature sensor converts the received radio-frequency signals to acoustic surface signals via an inverse piezoelectric effect, the radio-frequency receiving module processes the received radio-frequency signals with temperature information to temperature data signals and sends the temperature data signals to the microprocessor. The acoustic surface wave temperature sensing system in the utility model can perform a real-time monitoring of temperature of a plurality of (inspection tour) underground cable nodes, and is advantaged by convenience, fastness, and low cost.

Wireless passive surface acoustic wave (SAW) impedance load transducer

Abstract: A pressure transducer comprises an antenna, an input/output interdigital transducer (1), a piezoelectric substrate (2), a reference reflecting grating (3), a measurement reflecting grating (4) and an external impedance change sensor; a wireless signal sent out by a radio frequency enquiring unit is received by the antenna, and is converted into a surface acoustic wave (SAW) through the input/output interdigital transducer (1); the SAW is spread on the piezoelectric substrate (2), and is reflected after reaching to the reference reflecting grating (3) and the measurement reflecting grating (4); the reflected SAW is converted into a radio wave again through the input/output interdigital transducer (1), and the radio wave is sent out through the antenna; a radio frequency receiver receives the feedback signal sent out by the antenna; and the measurement of the wireless passive sensor is realized after the signal is processed and the information is extracted. The wireless passive surface acoustic wave (SAW) impedance load transducer has the advantages that the wireless measurement and the passivity of the transducer are realized; the read-out display is effectively improved; a sensing part which is easily influenced by the outside is separated from a signal transmitting part; and the application range of the transducer is enlarged.

Passive wireless surface acoustic wave stress sensor adopting three-layer stress transferring model

Abstract: The invention relates to a surface wave stress sensor based on a three-layer stress transferring model. The surface acoustic wave stress sensor provided by the invention comprises a piezoelectric substrate material, an interdigital transducer, a reverse grid, a small antenna and an adhesive agent used for sticking the sensor, wherein a surface acoustic wave resonator is adhered to a detected object by the adhesive agent. Different from the traditional surface acoustic wave stress sensor, a three-layer mechanical model, namely a detected structure substrate, an adhesive layer, an SAW (surface acoustic wave) resonance layer of the surface acoustic wave stress sensor, is established, a stress transferring formula and a stress transferring coefficient of the SAW sensor are deduced and the factors influencing the SAW sensor measuring result are achieved. The main factors influencing the sensor stress transferring contain the length of the sensor, the thickness of the adhesive layer, the modulus of elasticity, the thickness of an SAW quartz substrate, and the like. The thinner the adhesive layer is, the longer the SAW resonator is and the larger the modulus of elasticity of the material is, the better the detecting precision of the stress sensor is. The surface acoustic wave stress sensor is simple in structure, small in volume, light in weight, convenient to use and suitable for stress wireless remote monitoring under severe environment.

SAW-MEMS (surface acoustic waves-micro electro mechanical system) acceleration sensor and manufacturing method thereof

Abstract: The invention discloses an SAW-MEMS (surface acoustic waves-micro electro mechanical system) acceleration sensor which relates to the field of microelectronic inertial components. The acceleration sensor comprises an SAW metal interdigital transducer, a quartz plate and a silicon substrate, wherein the quartz plate is provided with a micro cantilever, and the silicon substrate is provided with a preset groove; the SAW metal interdigital transducer is manufactured on the micro cantilever in the quartz plate; the micro cantilever is bonded on the silicon substrate provided with the preset groove; the quartz plate is thinned through bonding with another silicon substrate without groove firstly, then transferred to the silicon substrate provided with the preset groove by using a bonding process; the SAW metal interdigital transducer is manufactured on the part, corresponding to the preset groove, of the quartz plate; and the micro cantilever structure is etched on the quartz plate, so that the SAW metal interdigital transducer is arranged on the micro cantilever. Because the acceleration sensor disclosed by the invention is prepared by using an MEMS process, the acceleration sensor is small in component size and suitable for mass production, therefore, the acceleration sensor provided by the invention is high in reliability, large in sensitive range, low in power consumption, high in precision, small in size and easy to package.

Elastic guided wave coupling resonator filter and associated manufacturing

Abstract: An elastic guided acoustic wave coupling resonator filter includes a dielectric layer interposed between piezoelectric substrates, with interdigital transducers on each substrate generally positioned at an interface between the substrates and the dielectric layer. The interdigital transducers on one substrate are aligned with the transducers on the opposing substrate and include cascaded filter tracks. The cascaded orientation between the two filter tracks includes either a differential connection or a balanced connection. As a result, the interdigital transducers are electrically isolated yet acoustically coupled to each other.

Surface acoustic wave measuring sensor

Abstract: The utility model relates to a surface acoustic wave measuring sensor, which comprises a piezoelectric base, an interdigital transducer and a reflector, wherein the piezoelectric base is used for sensing physical quantity to be measured, the interdigital transducer and the reflector are deposited on the upper surface of the piezoelectric base by a surface micromachining technology, the interdigital transducer receives driving energy needed by the work of a surface acoustic wave sensor by an antenna connected with the interdigital transducer, the driving energy is returned back to a radio frequency pulse echo signal, and the reflector is used for generating radio frequency pulse echo signal Compared with the existing sensor, the surface acoustic wave measuring sensor has the following technical characteristics: on the premise of guaranteeing a certain signal strength, physical quantity can be guaranteed to be measured in a large range and with high accuracy; the problem that the surface acoustic wave sensor in the prior art can meet only one rather than two indexes on the range and accuracy of signal measuring; the surface acoustic wave measuring sensor is simple in structure; and the physical quantity to be measured generates corresponding feedback signals by a method of analysis of a certain parameters, so that the problem of measuring the physical quantity accurately in a large range for the sensor is solved

Monolithically applied heating elements on saw substrate

Abstract: A surface acoustic wave (SAW) device comprising a piezoelectric substrate having a working surface with an active zone capable of propagating an acoustic wave on said working surface; at least one interdigital transducer on the working surface, having interdigital fingers aligned in the active zone for inducing or receiving surface acoustic waves in the active zone; and a heating element on the working surface; wherein the transducer, heating element and preferably a temperature sensor are monolithically formed on the substrate.

Development of a Wireless Love Wave Biosensor Platform for Multi-functional Detection

Abstract: A Love wave-based biosensor with a 440 MHz operating frequency was developed for simultaneous detection of two different concentrations of anti-dinitrophenyl-keyhole limpet hemocyanin (Anti-DNP-KLH) rabbit immunoglobulin G (IgG) in a single sensor. The sensor was composed of surface acoustic wave (SAW) reflective delay lines built from interdigital transducer (IDT) and several reflectors, a poly(methyl methacrylate) (PMMA) waveguide layer, and two sensitive films. To extract optimal device parameters, coupling of mode (COM) modeling was carried. According to the device parameters determined, the Love wave biosensor was fabricated and then wirelessly characterized by a network analyzer. Binding of anti-DNP IgG to DNP induced a change in the time positions of the original reflection peaks mainly due to the mass loading effect. The measured time positions were matched well with the predicted values from COM modeling. The sensitivities evaluated from the first and second sensitive films were 167.9 and 44.8 degµg-1ml-1, respectively.

Multi-wavelength ultrasonic standing wave device for non-invasive cell manipulation and characterisation

Abstract: Ultrasonic standing wave manipulation has many promising applications in cell biology, such as noncontact investigation of cell and tissue mechanics. In this paper, recent progress in developing a high frequency resonant chamber using a lithium niobate transducer is presented. This device is designed to sit on a petri dish or microscope slide, with the propagation direction parallel to the dish surface, in a configuration compatible with an optical microscope. It comprises a high frequency ultrasonic transducer with a low acoustic impedance transducer mounting, a polished reflector, and a set of precision spacers between the reflector and transducer. The prototype device demonstrates the feasibility of trapping microparticles with ultrasound radiation forces in multiple trapping sites, and the short wavelength reduces the separation of trapping sites to the same order as the cell dimensions. The basic design of device was validated with one dimensional modelling and finite element simulation. Experimental results of trapping 10 μm polystyrene beads correspond to simulated pressure distributions showing multiples of half-wavelength standing waves.

Electromechanical transducer device and analyte information acquiring apparatus

Abstract: To suggest an electromechanical transducer device with a high S/N ratio, an electromechanical transducer device includes a first substrate; electromechanical transducer elements two-dimensionally arrayed on a front surface of the first substrate and configured to provide conversion between acoustic waves and electric signals; an electric wiring substrate that is a second substrate electrically connected with a back surface of the first substrate; a first acoustic matching layer provided between the first substrate and the second substrate; an acoustic attenuating member arranged on a back surface of the second substrate; and a second acoustic matching layer provided between the second substrate and the acoustic attenuating member.