Showing papers on "Interdigital transducer published in 2014"

Ultra-wideband and high frequency resonators using shear horizontal type plate wave in LiNbO3 thin plate

Abstract: A cognitive radio system requires a tunable filter with a wide tunable range to compose a simple front-end. Because the tunable range is limited by the bandwidth (BW) of resonators, an ultra-wideband resonator is an important device to implement the tunable filter. The authors previously obtained low frequency resonators with a wide BWs of 26 to 29% and a large impedance ratios of 92 to 98 dB between resonance (fr) and anti-resonance frequencies (fa) using 0-th mode shear horizontal (SH0 mode) plate wave in a LiNbO3 plate. Also, a tunable filter with the tunable range of 13% was demonstrated. However, the frequency (fr =1.8 MHz and fa = 2.3 MHz) is too low for modern wireless communication. Also, the resonators suffered from ripples due to transverse mode between fr and fa. In this study, high frequency SH0 mode plate wave resonators (fr = 430–560 MHz and fa = 530–670 MHz) with a wide bandwidth and a large impedance ratio have been fabricated using an ultrathin LiNbO3 plate. The ripples were suppressed by an apodized interdigital transducer.

Loss reduction of longitudinal-type leaky surface acoustic wave by loading with high-velocity thin film

Abstract: A longitudinal-type leaky surface acoustic wave (LLSAW) has large inherent attenuation owing to the continuous radiation of two bulk waves. The attenuation of an LLSAW can be reduced by loading with an aluminum nitride (AlN) thin film with a higher bulk wave velocity than the substrate. In this study, to further reduce the attenuation of the LLSAW, we investigated the propagation properties of an LLSAW on an X-cut 36° Y-propagating LiNbO3 (X36°Y-LN) substrate with an AlN thin film deposited by an RF magnetron sputtering system with a long-throw sputter cathode, in which the substrate is not exposed to plasma directly, by measurement using an interdigital transducer (IDT) pair with a wavelength λ of 8.0 or 4.8 µm. The insertion loss and bulk wave radiation loss into the substrate from the IDTs were markedly decreased by loading with the AlN thin film. When the film thickness was 0.250 λ for λ = 8.0 µm, the measured propagation loss decreased approximately tenfold from 0.28 dB/λ for the sample without the film to 0.03 dB/λ with the film. Furthermore, the temperature coefficient of delay was also reduced by loading with the AlN thin film.

Mass-spring matching layers for high-frequency ultrasound transducers: a new technique using vacuum deposition

Abstract: We have developed a technique of applying multiple matching layers to high-frequency (>30 MHz) imaging transducers, by using carefully controlled vacuum deposition alone. This technique uses a thin mass-spring matching layer approach that was previously described in a low-frequency (1 to 10 MHz) transducer design with epoxied layers. This mass- spring approach is more suitable to vacuum deposition in highfrequency transducers over the conventional quarter-wavelength resonant cavity approach, because thinner layers and more versatile material selection can be used, the difficulty in precisely lapping quarter-wavelength matching layers is avoided, the layers are less attenuating, and the layers can be applied to a curved surface. Two different 3-mm-diameter 45-MHz planar lithium niobate transducers and one geometrically curved 3-mm lithium niobate transducer were designed and fabricated using this matching layer approach with copper as the mass layer and parylene as the spring layer. The first planar lithium niobate transducer used a single mass-spring matching network, and the second planar lithium niobate transducer used a single mass-spring network to approximate the first layer in a dual quarter-wavelength matching layer system in addition to a conventional quarter-wavelength layer as the second matching layer. The curved lithium niobate transducer was press focused and used a similar mass-spring plus quarter-wavelength matching layer network. These transducers were then compared with identical transducers with no matching layers and the performance improvement was quantified. The bandwidth of the lithium niobate transducer with the single mass-spring layer was measured to be 46% and the insertion loss was measured to be -21.9 dB. The bandwidth and insertion loss of the lithium niobate transducer with the mass-spring network plus quarter-wavelength matching were measured to be 59% and -18.2 dB, respectively. These values were compared with the unmatched transducer, which had a bandwidth of 28% and insertion loss of -34.1 dB. The bandwidth and insertion loss of the curved lithium niobate transducer with the mass-spring plus quarter-wavelength matching layer combination were measured to be 68% and -26 dB, respectively; this compared with the measured unmatched bandwidth and insertion loss of 35% and -37 dB. All experimentally measured values were in excellent agreement with theoretical Krimholtz-Leedom-Matthaei (KLM) model predictions.

Acoustic wave device

Abstract: An acoustic wave device includes a piezoelectric substrate, an interdigital transducer (IDT) electrode provided on an upper surface of the piezoelectric substrate, a first dielectric film covering the upper surface of the piezoelectric substrate to cover the IDT electrode, and a second dielectric film covering an upper surface of the first dielectric film The second dielectric film includes a thin portion positioned in a tip region of electrode fingers of the IDT electrode and a thick portion which is positioned in a middle region of the IDT electrode and is thicker than the thin portion The acoustic wave device suppresses spurious emission and has superior passband characteristics

Piezoelectric transducer device with flexible substrate

Abstract: In an embodiment, a transducer device comprises a flexible substrate and a plurality of tiles coupled to the substrate. The tiles each include a plurality of piezoelectric transducer elements and a base adjoining and supporting the plurality of piezoelectric transducer elements. The substrate has disposed therein or thereon signal lines to serve as a backplane for communication to, from and/or among integrated circuitry of the tiles. In another embodiment, the integrated circuitry of the tiles are each pre-programmed to implement any of a respective plurality of operational modes. Signals exchanged with the tiles via the flexible substrate facilitate operation of the transducer device to provide a phased array of transducer elements.

Acoustic filters based on thin single crystal LiNbO 3 films: Status and prospects

Abstract: Lithium niobate has been extensively used in the Surface Acoustic Wave (SAW) industry for its excellent piezoelectric properties. In the last twelve years, the interest has been raised towards making this material available in the thin film form for SAW or Bulk Acoustic Wave (BAW) applications, and even for Lamb wave devices. This paper reviews both deposition or thin film transfer techniques to obtain lithium niobate thin films. It also gives a brief overview of the applications of these thin films. Finally, we open new perspectives for this technology with the emerging field of tunable acoustic filters, which need extremely large piezoelectric properties to demonstrate satisfying performance.

Magnetoelectric surface-acoustic-wave magnetic-field sensor and manufacturing method thereof

Abstract: The invention discloses a magnetoelectric surface-acoustic-wave magnetic-field sensor and a manufacturing method thereof and belongs to the technical field of electronic function materials and devices. The magnetoelectric surface-acoustic-wave magnetic-field sensor comprises a magnetostriction substrate, a metal buffer layer and a piezoelectric film, wherein the metal buffer layer is made of metallic titanium or chromium and arranged between the magnetostriction substrate and the piezoelectric film, interdigital transducers with two ports are arranged on the upper surface of the piezoelectric film, and the interdigital transducers and the piezoelectric film constitute a surface-acoustic-wave resonator. Each interdigital transducer comprises an input electrode, an output electrode, an input-end reflecting grating and an output-end reflecting grating, wherein the input-end reflecting grating is arranged on the outer side of the input electrode, and the output-end reflecting grating is arranged on the outer side of the output electrode. The thickness of the piezoelectric film ranges from 0.3-1 micrometer, the thickness of the magnetostriction substrate is larger than two times of wavelength of the surface-acoustic waves. By the aid of the high-orientation piezoelectric film and magnetostriction strips with uniaxial anisotropism and Young's modulus effect, the sensor is miniaturized, high in sensitivity and good in consistency. The manufacturing method is simple and applicable to probing of magnetic fields.

Effective suppression method for 2 nd nonlinear signals of SAW devices

Abstract: Linearity performances are getting one of the most important characteristics of surface acoustic wave (SAW) duplexers because nonlinear signals generated in RF front-end of cellar phone handsets deteriorate the receiver sensitivities significantly. In this paper, the generation mechanisms of the 2nd order nonlinear signals of SAW resonators/duplexers on a 42°Y-X LiTaO 3 substrate and an effective suppression method for them are discussed. The crystalline asymmetry properties of substrates are focused on as the one possibility of the occurrence factor of the 2nd order nonlinear signals. Additionally, based on this hypothesis, an interdigital transducer (IDT) design which realizes the cancellation of the crystalline asymmetry effect is proposed to improve the linearity. As the result, the 2nd order harmonics level of the one-port SAWresonators and the 2nd order intermodulation distortion (IMD2) levels of the SAW duplexers have been improved up to about 25dBm and 20dBm, respectively.

Multi-sensor recognition-based temperature detection system

Abstract: The present invention provides a multi-sensor recognition-based temperature detection system, which comprises a reader, a broadband antenna and N surface acoustic wave sensors, wherein each surface acoustic wave sensor comprises a one-way interdigital transducer and a frequency orthogonal reflection grating code group; the reader sends a query signal to the surface acoustic wave sensors via the broadband antenna; the surface acoustic wave sensors receive an orthogonal frequency coded signal and transforms the orthogonal frequency coded signal into a surface acoustic wave signal according to the trigger of the query signal; the reader receives an echo signal via the broadband antenna. The remote multipoint-connection anti-interference surface acoustic wave wireless sensors based on the combination of orthogonal frequency and code division multiplexing code is adopted, the near-far effect of a passive sensor system for code division multiplexing coding is solved, and demands of an intelligent power grid on the wireless monitoring on the temperature of power equipment are met.

A surface acoustic wave micropump to pump fluids from a droplet into a closed microchannel using evaporation and capillary effects

Abstract: A new method for converting a microdroplet on a piezoelectric substrate into continuous fluid flow in microchannels is presented. An interdigital transducer with 27.5 MHz center frequency is fabricated on a 1280 yx-LiNbO3 piezoelectric substrate for exciting surface acoustic wave. A PDMS (Polydimethylsiloxane) microchannel is mounted on the piezoelectric substrate. One end of the microchannel is connected with water absorbing paper, while the other end of the microchannel is in touch with a droplet to be converted. The surface acoustic wave is used for controlling the evaporation velocity of the fluid in the microchannel. Part of fluid in the droplet can be entered into the microchannel and transported there due to the evaporation and capillary effects. Red dye solution is used to demonstrate the conversion of the droplet and the transportation of the fluid in the microchannel. Results show that the droplet on the piezoelectric substrate can successfully be converted into continuous fluid. The flow velocity is increased with the power of the electric signal applied to the interdigital transducer. Average flow velocity is 0.0235μl/s when the power of the electric signal is 30.0dBm. The work is helpful for piezoelectric microfluidic devices for biochemical analysis.

A transversely coupled phononic surface acoustic wave transducer

Abstract: A concept is demonstrated for the development of a phononic surface acoustic wave interdigital transducer (IDT) able to excite acoustic waves in a transverse manner with respect to the applied electric field. The basic principles of the design and fabrication of the transversely coupled phononic transducer are presented. More specifically, the IDT consists of a regular interdigital electrode configuration on which a 2D array of low profile masses is superimposed. The transversely coupled mode of excitation is explained in terms of the specific localization of the elastic energy along with the operation within the complete frequency bandgap of the composite transducer grating. The experimental results provide solid evidence for the suggested mode of operation.

Design and fabrication of nanoscale IDTs using electron beam technology for high-frequency SAW devices

Abstract: High-frequency Rayleigh-mode surface acoustic wave (SAW) devices were fabricated for 4G mobile telecommunications. The RF magnetron sputtering method was adopted to grow piezoelectric aluminum nitride (AlN) thin films on the Si3N4/Si substrates. The influence of sputtering parameters on the crystalline characteristics of AlN thin films was investigated. The interdigital transducer electrodes (IDTs) of aluminum (Al) were then fabricated onto the AlN surfaces by using the electron beam (e-beam) direct write lithography method to form the Al/AlN/Si3N4/Si structured SAW devices. The Al electrodes were adopted owing to its low resistivity, low cost, and low density of the material. For 4G applications in mobile telecommunications, the line widths of 937 nm, 750 nm, 562 nm, and 375 nm of IDTs were designed. Preferred orientation and crystalline properties of AlN thin films were determined by X-ray diffraction using a Siemens XRD-8 with CuKα radiation. Additionally, the cross-sectional images of AlN thin films were obtained by scanning electron microscope. Finally, the frequency responses of high-frequency SAW devices were measured using the E5071C network analyzer. The center frequencies of the high-frequency Rayleigh-mode SAW devices of 1.36 GHz, 1.81 GHz, 2.37 GHz, and 3.74 GHz are obtained. This study demonstrates that the proposed processing method significantly contributes to high-frequency SAW devices for wireless communications.

Virtual deterministic lateral displacement for particle separation using surface acoustic waves

Abstract: A microfluidic device for separating or sorting particles in a fluid including: a substrate; a plurality of interdigital transducers on the substrate; a microfluidic channel adapted to have fluid flow within, located over the interdigital transducers, the microfluidic channel having a width, wherein: the interdigital transducers are located within the width of the microfluidic channel; and application of a signal to the interdigital transducers produces a force field at an angle to the fluid flow direction within the microfluidic channel. In addition, a method for separating or sorting particles using a device having a plurality of interdigital transducers on a substrate and a microfluidic channel located over the interdigital transducers, the method including: positioning the interdigital transducers within the microfluidic channel width; inserting into the microfluidic channel a solution having particles with various properties; and applying a signal to the interdigital transducers to produce a force field at an angle to a fluid flow direction within the microfluidic channel to sort and/or physically separate the particles into groups of particles with the same property.

Surface acoustic wave device and composite module including same

Abstract: A surface acoustic wave device includes a piezoelectric substrate including an interdigital transducer located on one principal surface thereof, an insulating layer arranged around the interdigital transducer, a cover layer arranged over the insulating layer and the interdigital transducer, and a columnar electrode penetrating through the insulating layer and the cover layer, and connected to the interdigital transducer through a connection wiring, wherein a buffer layer is arranged on the other principal surface of the piezoelectric substrate.

Sensor for use in long-distance passive wireless temperature monitoring of power equipment and system thereof

Abstract: The invention provides a sensor for use in long-distance passive wireless temperature monitoring of power equipment. The sensor comprises a one-way interdigital transducer and a frequency orthogonal reflecting grating chip group, wherein the frequency orthogonal reflecting grating chip group comprises n chips which are arranged in sequence and construct a sensor code; each chip consists of a periodic electrode, thereby forming reflection of one orthogonal sub-frequency; sub-frequencies formed among the chips are orthogonal; the time domain length of each chip reflected signal keeps consistent, and the orthogonality condition is satisfied. The invention further provides a corresponding system. By adopting a long-distance multi-point-connection and anti-interference sound surface wave wireless sensor method, the 'near-far effect' of a code division multiplexing coding passive sensor system is eliminated, and requirement of a smart power grid on wireless monitoring of the temperature of power equipment can be met.

X-ray diffraction on the X-cut of a Ca3TaGa3Si2O14 single crystal modulated by a surface acoustic wave

Abstract: The result of X-ray diffraction study on a single crystal of the calcium-gallogermanate family Ca3TaGa3Si2O14 (CTGS) modulated by a surface acoustic wave (SAW) is presented. The power flow angle for SAW propagating along the X2 axis of the X-cut in CTGS was measured. The rocking curves for the CTGS crystal were recorded at different amplitudes of an input high frequency electric signal on interdigital transducer used to excite a SAW. Based on the data obtained, intensity dependence of diffraction satellites on the amplitude of electric signal exciting a SAW was built. Numerical simulation of the crystal rocking curves and dependence of diffraction satellite intensities on the SAW amplitude enabled the selection of a set of material constants at which the most complete coincidence of experimental and calculated results is observed.

Piezoelectric transducer device with lens structures

Abstract: In an embodiment, a probe device includes a portion having a curved surface and a plurality of tiles variously coupled to the curved surface. The tiles each include a plurality of piezoelectric transducer elements and a base adjoining and supporting the plurality of piezoelectric transducer elements. The probe device further comprises curved lens portions each coupled to a respective one of the plurality of tiles, wherein for each of the tiles, the plurality of piezoelectric transducer elements of the tile are to propagate a wave toward the respective curved lens portion. In another embodiment, the probe device further comprises a sheath material surrounding the curved lens portions.

Passive wireless temperature measuring antenna device

Abstract: The invention discloses a passive wireless temperature measuring antenna device, and belongs to the technical field of temperature monitoring devices of substation equipment. The passive wireless temperature measuring antenna device facilitates wireless monitoring of the contact temperature of the substation equipment. According to the technical scheme of the passive wireless temperature measuring antenna device, a passive wireless temperature measuring sensor comprises an interdigital transducer, a reflecting grating, a piezoelectric substrate and a sensor antenna, wherein the interdigital transducer and the reflecting grating are arranged on the piezoelectric substrate, the sensor antenna is electrically connected with the interdigital transducer, and a helical antenna is adopted in the sensor antenna. The passive wireless temperature measuring antenna device is applicable to the electric power department.

Acoustic surface wave resonator and manufacturing method thereof

Abstract: The invention discloses an acoustic surface wave resonator and a manufacturing method of the acoustic surface wave resonator. The acoustic surface wave resonator comprises an interdigital transducer, reflecting gratings and resonance cavities, the reflecting gratings are arranged on the two sides of the interdigital transducer, and the resonance cavities are located between the interdigital transducer and the reflecting gratings or located in the middle of the interdigital transducer. The structure of the double-module SAW resonator is fundamentally different from that of traditional double modules, according to the former design of an SAW resonator, two single modules are designed to be placed on one chip, and one whole design instead of two independent designs on one chip is adopted for the acoustic surface wave resonator, so that the resonator is not prone to being affected by difference in the manufacturing process, the size of the chip is about half that of the chip adopting the design of the traditional resonator with the two single modules, and the chip is lower in cost. The single-port double-module SAW resonator serving as a wireless passive sensor in a difference measurement mode is applied widely, for example, the SAW resonator can be used as a temperature sensor, a pressure sensor, an acceleration/vibration sensor, a strain sensor and the like.

Elastic Softening of Surface Acoustic Wave Caused by Vacancy Orbital in Silicon Wafer

Abstract: We have performed surface acoustic wave (SAW) measurements to examine vacancies in a surface layer of a boron-doped silicon wafer currently used in semiconductor industry. A SAW with a frequency of fs = 517 MHz was optimally generated by an interdigital transducer with a comb gap of \(w=2.5\) µm on a piezoelectric ZnO film deposited on the (001) silicon surface. The SAW propagating along the [100] axis with a velocity of \(v_{\text{s}}=4.967\) km/s is in agreement with the Rayleigh wave, which shows an ellipsoidal trajectory motion in the displacement components ux and uz within a penetration depth of λp = 3.5 µm. The elastic constant Cs of the SAW revealed the softening of ΔCs/Cs = 1.9 × 10−4 below 2 K down to 23 mK. Applied magnetic fields of up to 2 T completely suppress the softening. The quadrupole susceptibilities based on the coupling between the electric quadrupoles Ou, Ov, and Ozx of the vacancy orbital consisting of Γ8–Γ7 states and the symmetry strains eu, ev, and ezx associated with the SAW ac...

Atomisation apparatus using surface acoustic wave generation

Abstract: An apparatus for atomising liquid, including a piezoelectric substrate (1) having a working surface (3), and a peripheral edge (7) extending along a side of the working surface, an interdigital transducer (2) located on the working surface for generating surface acoustic waves (SAW) in the working surface, and a liquid delivery arrangement including a porous member (8) for supplying the liquid to be atomised, wherein the porous member is in contact with the peripheral edge of the piezoelectric substrate.

Single-ended pair SAW resonator with high quality factors

Abstract: The invention relates to a single-ended pair SAW resonator with high quality factors. The single-ended pair SAW resonator comprises a piezoelectric substrate (22), an interdigital transducer (24), a first reflector (23) and a second reflector (25), wherein the interdigital transducer (24) is placed on the surface of the piezoelectric substrate (22), and the first reflector (23) and the second reflector (25) are distributed on the two sides of the interdigital transducer (24). The edge space between the first reflector (23) and the interdigital transducer (24) and the edge space between the second reflector (25) and the interdigital transducer (24) are both 0.625 lambada, and the lambada is the wave length of sound waves. The interdigital transducer (24) is of a Blackman window function trimmed mean weight structure. Aluminum material electrodes are all used in the interdigital transducer (24), the first reflector (23) and the second reflector (25), and the duty ratio of the electrodes is 1.3-1.5. The film thickness of the aluminum electrode of the interdigital transducer (24), the film thickness of the aluminum electrode of the first reflector (23) and the film thickness of the aluminum electrode of the second reflector (25) are 1.1-1.5% lambada. The single-ended pair SAW resonator has the advantages of being small in size, high in Q value, small in OOB fluctuation and the like.

Mode Selective Actuator-Sensor System for Lamb Wave-Based Structural Health Monitoring

Abstract: Structural Health Monitoring (SHM) based on Lamb waves, a type of ultrasonic guided waves, is a promising method for in-service inspection of composite structures. In this study mode selective actuators and sensors are investigated to excite a particular Lamb wave mode in composite plates. The actuator and sensor exhibit an interdigital transducer design. In order to describe the complex displacement fields of

Micro valve and method for controlling transport of fluid by virtue of micro valve

Abstract: The invention discloses a micro valve and a method for controlling the transport of a fluid by virtue of the micro valve. The micro valve comprises a piezoelectric substrate, wherein an interdigital transducer is arranged on the working surface of the piezoelectric substrate, and a first PDMS (polydimethylsiloxane) microgroove is formed in a sound transmission path of sound acoustic waves excited by the interdigital transducer; an opening in the top end of the first PDMS microgroove is covered by heat conduction sheet metal; a second PDMS microgroove is formed in the upper surface of the heat conduction sheet metal; a soft PDMS slice is connected to the opening in the top end of the second PDMS microgroove; a PDMS polymer is connected to the top end of the second PDMS microgroove; two micro-channels are soft-photoetched in the PDMS polymer; nicks communicated with the micro-channels are formed in positions, corresponding to the soft PDMS slices, at the bottom end of the PDMS polymer; the edges of the nicks are connected with the soft PDMS slices in a sealing way. The micro valve and the method have the advantages that the micro valve can be opened and closed only by virtue of the surface acoustic waves without control equipment such as an air pump with a larger size, so that the micro valve is simple in structure, small in size and quick in response, and can be easily integrated in a micro-flow device.

Surface acoustic wave formaldehyde gas sensor based on electric conduction composite sensitive material

Abstract: The present invention provides a surface acoustic wave formaldehyde gas sensor based on a composite sensitive material. The sensor comprises a piezoelectric substrate (1), an interdigital transducer (2), and an electric conduction composite sensitive material (3), wherein the electric conduction composite sensitive material (3) comprises electric conduction particles (4) and an insulation material. According to the present invention, the insulation material (5) selectively absorbs formaldehyde gas, and then the volume is changed so as to change the volume of the electric conduction composite sensitive material, such that the distance between the electric conduction particles (4) inside the electric conduction composite sensitive material (3) is changed so as to change conductivity of the electric conduction composite sensitive material (3) and produce the acoustic-electric effect of the surface acoustic wave, such that the sensitivity of the sensor on the formaldehyde gas is increased.

Acoustic wave element

Abstract: An acoustic wave element includes: a piezoelectric substrate; an IDT (Interdigital Transducer) formed on the piezoelectric substrate; and an end face of the piezoelectric substrate that is formed on at least one end of the IDT in a propagation direction of an acoustic wave; wherein when a wavelength of the acoustic wave which the IDT excites is expressed by “λ” and a metallization ratio of the IDT is expressed by “D”, a distance between an inner end of an electrode finger of the IDT nearest to the end face and the end face is equal to or more than 7λ/16+D×λ/4 and equal to or less than 3λ/4+Dλ/4.

Device for achieving parallel heating of detection zones in paper-based micro-flow device by employing acoustic surface wave

Abstract: The utility model discloses a device for achieving parallel heating of a plurality of detection zones in a paper-based micro-flow device by employing an acoustic surface wave. The device comprises a piezoelectric substrate, a signal generator, a polydimethylsiloxane (PDMS) micro container and a metal heat transfer plate, wherein the polydimethylsiloxane micro container is used for containing heated microfluid; the metal heat transfer plate is used for transferring heat to the plurality of detection zones in the paper-based micro-flow device; an interdigital transducer is arranged on the work surface of the piezoelectric substrate; a hydrophobic layer is arranged on a sound transmission path of the acoustic surface wave excited by the interdigital transducer; the bottom of the PDMS micro container is tightly attached and connected to the hydrophobic layer; the metal heat transfer plate covers the top of the PDMS micro container; a plurality of heat transfer zones are formed at the end part of the periphery of the metal heat transfer plate in a manner of extending outwards; the position of each heat transfer zone corresponds to the position of each detection zone in the paper-based micro-flow device. The device has the advantages that the generated heat is transferred to each detection zone in the paper-based micro-flow device through the heat transfer zones of the metal heat transfer plate when the temperature of the heated microfluid raises after being radiated by the acoustic surface wave, so that parallel and simultaneous heating of reaction liquid to be tested in the plurality of detection zones is achieved.

Spectral theory of natural unidirectionality of SPUDT for BG waves

Abstract: A single-phase unidirectional interdigital transducer SPUDT is modelled by a system of periodic metal strips on a piezoelectric halfspace carrying Bleustein-Gulyaev BG wave. The dispersion relation for BG surface wave, as well as some relations between forward and backward waves in the system are discussed. Natural unidirectionality is explained in this way.

Acoustic surface wave pressure sensing label for underground pipes

Abstract: The invention discloses an acoustic surface wave pressure sensing label for underground pipes. The sensing label comprises a label chip, a label antenna and a label outer shell arranged outside the label chip. The label chip comprises a piezoelectric substrate, an interdigital transducer deposited on the piezoelectric substrate and reflecting gratings. The piezoelectric substrate is formed by piezoelectric single crystals. The interdigital transducer is a double-way interdigital transducer. The acoustic surface wave pressure sensing label for the underground pipes has the advantages of being free of sources and lines, long in identification distance, high in antijamming capability and suitable for severe environments.

Electrical equipment remote passive wireless temperature monitoring system and method

Abstract: The invention provides an electrical equipment remote passive wireless temperature monitoring method which comprises the steps of 1, emitting a query signal to a surface acoustic wave sensor by a reader through a wide-band antenna; 2, receiving an OFC (Orthogonal Frequency Coding) signal by the surface acoustic wave sensor through a single interdigital transducer according to the trigger of the query signal and converting the OFC signal into a surface acoustic wave signal; 3, reflecting the surface acoustic wave signal by a frequency orthogonal reflecting grating chip and passing the single interdigital transducer to form an echo signal; 4, receiving the echo signal by the reader through the wide-band antenna According to the remote multipoint connection and anti-interference surface acoustic wave wireless sensor method based on the combination of orthogonal frequency and code division multiplexing coding, the far and near effect of the code division multiplexing coding passive sensor system is solved, and the requirement of a smart power grid on the wireless monitoring of temperature of electrical equipment is met