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Construction of smart city has become a historical trend in the world. The management of underground pipes and the intelligent concrete are the main part of building smart city in China. Compared with the available electronic marker system, SAW-RFID system has shown excellent properties: truly passive, strong penetrating capability, long service-life, sensing and ID integration, and etc. Thus, SAW-RFID...
Diamond has the highest sound velocity among all materials and has been applied in high frequency surface acoustic wave (SAW) devices in the gigahertz range. To date, numerous researches have reported that the SAW devices built on a diamond wafer can work in the frequency range from 2 GHz to 10 GHz. S. Fujii et al. reported that the one-port resonator with an interdigital transducer (IDT)/AlN/single...
Coupling between surface acoustic waves (SAW) and arrays of mechanical resonators has appeared early in SAW history as a potential means to slow down wave propagation through mass-loading, in particular by creating corrugations on the substrate surface. This concept has been revisited over the past few years in the context of locally-resonant phononic crystals where pillars deposited on a homogeneous...
Acoustic delay lines based on Al0.85Sc0.15N thin film hybrid transducers were investigated by finite element modeling. It was found that an acoustic impedance matching between transducer and non-piezoelectric substrate material plays a crucial role to efficiently excite a traveling surface acoustic wave (SAW) through the BAW piston motion. Test devices based on the 2.5 um thick Al0.85Sc0.15N piezoelectric...
Recently, it was shown that heavily doped AlN film possess the high piezoelectricity by Akiyama et al [1]. On the other hand, SAW devices were widely used as filters and sensors. Among them, SAW in ScAlN film is attracting a lot of attention because this SAW devices have high electromechanical coupling coefficient K2. We analyzed the K2 value in Sc0.4Al0.6N was increased by c-axis tilted angle θ becoming...
I.H.P. SAW (Incredible High-Performance SAW) has a novel multi-layered structure to confine SAW energy in substrate surface area, and it shows extremely high quality (Q) factor, low temperature coefficient of frequency (TCF) and improved electromechanical coupling coefficient (K2). This paper introduces its mechanism of the high acoustic Q factor, both theoretically and experimentally, and its applications...
Surface acoustic wave (SAW) devices are widely used as acoustic-electronic components today. The lithium niobate was often used as the substrate of SAW devices for its higher electromechanical coupling coefficient. In some applications like RFID tags and sensors, SAW devices have a long delay line and the energy loss of diffraction is considerable. Phononic crystals (PnC) have properties of band gaps...
Recently we reported on fabrication and characterization of a novel type of hybrid resonator in which BAW transforms into SAW due to a periodic pillar pattern of piezoelectric material. This device looks promising thanks to high achievable electromechanical coupling (over 4%) and possibility for application as sensor in harsh environment when using AlScN as piezoelectric. The main feature of the device...
Nanoparticle manipulation has a variety of potential applications, from two-dimensional material fabrication to biomedical engineering. Pattern and transportation of nanoparticles has been receiving increasing attention in recent years. Ultrasound as a mechanical wave has proven to be the most effective in the manipulation of micro-objects in a non-contact and non-invasive fashion. However, due to...
ScAlN films are attractive for SAW devices with high electromechanical coupling coefficient K2. In previous study, we analyzed K2 in c-axis-tilted Sc0.4Al0.6N film / diamond substrate. The K2 of c-axis-tilted film was increased, compared with that of the c-axis-normally-oriented film. However, it is difficult to perform experiments because diamond substrate are very expensive. In this study, K2 of...
Small sized surface acoustic wave (SAW) devices with high performances have been strongly demanded. In order to fulfill these requirements, we have developed a small sized temperature compensated SAW (TC-SAW) duplexer. The die size of current SAW devices highly depends on the size of interdigital transducers (IDTs) which is proportional to the acoustic velocity of the SAW. Therefore, we tried to lower...
With ever increasing requirements on the linearity of SAW signal processing devices in mobile communication, nonlinear effects like harmonic generation and intermodulations have gained renewed interest and have become an active field of research with the aim of identifying their origin, analyzing and counteracting them. In this contribution we focus on second-harmonic generation in SAW resonators...
Surface acoustic wave gyroscopes are a solution for inertial navigation applications which require operability through high levels of shock and vibration. Integration of multiple axis gyroscopes in a small device are also needed to reduce the size and weight of the sensor system. Here we present a two-axis SAW gyroscope using bulk excited surface wave through the Lithium Niobate wafer. For the bulk...
A CRF/DMS filter is simulated using “Layers” software [1-2]. We analyze a few different CRF/DMS structures, including the 10-port CRF device with passband frequency close to 1842.5 MHz including 5 IDTs, 8 “gap IDTs” and 2 reflectors. This TC SAW structure has a thick SiO2 over layer covering 274 Cu electrodes on a 128° LiNbO3 substrate. In addition to the electrical network parameters for the filter,...
Conventional acoustic wave correlators are known for their small size (nearly 105 times smaller than an analogous electromagnetic correlator), zero DC power consumption, and linearity. Reconfigurable orthogonally coded correlators could be used at the front-end of a RF transmit and receive chain to provide cross-correlation properties that can aide in simultaneous transmit and receive (STAR) systems...
In order to minimize losses due to bulk-acoustic radiation, ‘leaky’ SAW resonators on rotated Y-cut LiTaO3 typically employ synchronous design, with all the electrodes in the IDT and in the reflectors sharing the same periodicity and electrode shape. The change in the electric connection pattern between the IDT and the reflectors creates an electric discontinuity, which can serve as an additional...
In general surface acoustic wave (SAW) devices are made on piezoelectric substrates, hence difficult to integrate with circuits made on silicon. SAW devices can be realized on a silicon substrate using a film of piezoelectric material in conjunction with interdigital transducers (IDT) facilitating monolithic integration of SAW devices with circuits. Normally, SAW resonators consist of reflector gratings...
A compact SAW resonator on silicon substrate has been proposed based on complete reflection property of shear horizontal surface waves at free edges and the Love wave generation capability of ZnO film in conjunction with IDT, the proposed device was fabricated and characterized. Love waves are excited in the overlaid ZnO film on silicon substrate and vertical grooves are micromachined into silicon...
For mobile communication, acoustic wave filters are being continuously required better steepness of a passband and a smaller temperature coefficient of frequency (TCF). Recently, various Hetero Acoustic Layer (HAL) types of surface acoustic wave (SAW) devices were reported by different groups including us [1-5]. HAL SAW devices inherently have many variations of structure and a lot of potentials....
Since the beginning of using piezoelectric single crystals for highly-precise microacoustic components rigorous knowledge of material constant (MC) sets was an indispensable requirement for mastering the subject. The sets have to be both accurate and complete. Accuracy is important for acceptable agreement between device simulation and experimental reality, completeness preferentially plays a role...
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