Acoustic Delay Research Articles

Adjustable stereo path design method based on pin-sculpture acoustic topological insulator with Z-dislocation defect immunity

The field of topological protected wave engineering, inspired by quantum mechanics, has generated significant interest. Acoustic analogs of electronic topological insulators provide new opportunities for manipulating sound propagation with unconventional acoustic edge modes that are immune to backscattering. Numerous reports have been published on the design of two-dimensional acoustic topological insulators (ATIs). However, the sound path of a two-dimensional design is simple, and its ability to control sound waves is limited. On the other hand, the design of 3D ATIs is relatively complex, making it difficult to manufacture and limiting its versatility. Based on the design idea of the 2D ATIs, inspired by the art named 3D pin-sculpture, an adjustable structure of a finite size consisting of spindle-shaped units with a variable cross section is designed to realize flexible path transformation. Furthermore, unlike two-dimensional structural defects, such as cavities and disorder, the analysis of vertical dislocation defects in finite-sized structures allows for the design of local sound propagation along the z-direction, providing a concept for constructing a stereo path. The designed structure also serves two functions: acoustic switch and delay. This idea offers an alternative approach to designing complex sound transmission paths.

Recovery rate after acute acoustic trauma: a case series and meta-analysis.

Steroids given systemically, locally, or both are the mainstay of treatment for acute acoustic trauma (AAT). The overall recovery rate (full, partial, and none) is undetermined. Original case series and systematic literature review. Case series of a tertiary referral center and a systematic literature review. Cases of AAT between 2012 and 2022 were retrospectively analyzed for demographics, acoustic trauma characteristics, treatment modality and delay and prognosis. This case series was added to the series identified by a systematic literature review. This review included "Medline" via "PubMed", "EMBASE", and "Google scholar". All series were pooled for meta-analysis defining prognosis following steroidal treatment for AAT patients. The pooled analyses included 662 ears, out of which 250 underwent complete recovery of hearing (overall proportion = 0.2809, 95%confidence interval [CI] = 0.1611-0.4178). Any recovery was recorded for 477 ears (overall proportion = 0.7185, 95% CI = 0.5671-0.8493) and no recovery was documented for 185 ears (overall proportion = 0.2815, 95% CI = 0.1507-0.4329). The rate of overall recovery for AAT is around 70%, and around 30% for full recovery when steroids are initiated within the first 2 weeks following the insult.

Void-Engineered Metamaterial Delay Line with Built-In Impedance Matching for Ultrasonic Applications

Metamaterials exhibit unique ultrasonic properties that are not always achievable with traditional materials. However, the structures and geometries needed to achieve such properties are often complex and difficult to obtain using common fabrication techniques. In the present research work, we report a novel metamaterial acoustic delay line with built-in impedance matching that is fabricated using a common 3D printer. Delay lines are commonly used in ultrasonic inspection when signals need to be separated in time for improved sensitivity. However, if the impedance of the delay line is not perfectly matched with those of both the sensor and the target medium, a strong standing wave develops in the delay line, leading to a lower energy transmission. The presented metamaterial delay line was designed to match the acoustic impedance at both the sensor and target medium interfaces. This was achieved by introducing graded engineered voids with different densities at both ends of the delay line. The measured impedances of the designed metamaterial samples show a good match with the theoretical predictions. The experimental test results with concrete samples show that the acoustic energy transmission is increased by 120% and the standing wave in the delay line is reduced by over a factor of 2 compared to a commercial delay line.

GNSS-A Network Solution with Zenith Acoustic Delay Estimation

The ocean sound speed changes drastically with time and space. It is almost impossible to achieve centimeter-level-precision Global Navigation Satellite System (GNSS)-Acoustic (GNSS-A) positioning without regarding spatio-temporal variations of sound speed. Inspired by the atmospheric delay estimation, we define zenith acoustic delay (ZAD) as the zenith-direction ranging error sourced by the sound speed variations, and then it is decomposed into one temporal component and two horizontal components for the sound speed variations in time and space, respectively. We propose a network solution with the three ZAD components of each seafloor geodetic point as common parameters to be estimated, and then present a piece-wise estimation to characterize their time-varying nature. To remedy the ray bending effect this study is implemented in the context of the ray tracing algorithm based on a reference sound speed profile (SSP). Experimental tests show that the proposed network solution improves ZAD estimation and results in a better position determination as compared to the single-point positioning (SPP) solution. The proposed network solution for a single campaign can achieve a horizontal positioning precision better than 5 cm (1-sigma) for the seafloor geodetic array centroid. The temporal variation of ZAD is up to one meter while the horizontal variations vary within a few decimeters in the time domain and show an azimuthal asymmetry in space.

Differential Game-Based Deep Reinforcement Learning in Underwater Target Hunting Task.

To meet requirements for real-time trajectory scheduling and distributed coordination, underwater target hunting task is challenging in terms of turbulent ocean environments and dynamic adversarial environment. Despite the existing research in game-based target hunting area, few approaches have considered dynamic environmental factors, such as sea currents, winds, and communication delay. In this article, we focus on a target hunting system consisted of multiple unmanned underwater vehicles (UUVs) and a target with high maneuverability. Besides, differential game theory is leveraged to analyze adversarial behaviors between hunters and the escapee. However, it is intractable that UUVs have to deploy an adaptive scheme to guarantee the consistency and avoid the escape of the target without collision. Therefore, we conceive the Hamiltonian function with Leibniz's formula to obtain feedback control policies. In addition, it proves that the target hunting system is asymptotically stable in the mean, and the system can satisfy Nash equilibrium relying on the proposed control policies. Furthermore, we design a modified multiagent reinforcement learning (MARL) to facilitate the underwater target hunting task under the constraints of energetic flows and acoustic propagation delay. Simulation results show that the proposed scheme is superior to the typical MARL algorithm in terms of reward and success rate.

A Voltage-Controlled Surface Acoustic Wave Oscillator Based on Lithium Niobate on Sapphire Low-Loss Acoustic Delay Line.

In this work, we investigate, for the first time, a low phase noise and wide tuning range voltage-controlled surface acoustic wave oscillator (VCSO) based on a lithium niobate on sapphire (LNOS) low-loss acoustic delay line (ADL). The thin-film LN/SiO2 bilayer acoustic waveguide, together with the single-phase unidirectional transducer (SPUDT) design, is key to attaining low insertion loss (IL) by enhancing energy confinement and directionality. Based on a high-performance ADL with an IL of only 5.2 dB, a fractional bandwidth (FBW) of 5.38%, and a group delay of 110 ns, the VCSO is implemented by commercially available circuit components using a series-resonant topology. The LNOS ADL oscillator operates at 888 MHz, showcasing a low phase noise of -94.1 dBc/Hz at 1-kHz offset and a root-mean-square (rms) jitter of only 30.26 fs (integrated from 12 kHz to 20 MHz) while only consuming 16 mA of supply current. Featuring a wide frequency tuning range of 6630 ppm, the proposed VCSO is a promising low-noise, low-power, and high-frequency timing device for emerging applications.Index Terms- Acoustic delay line (ADL), jitter, lithium niobate (LN), oscillator, phase noise, surface acoustic wave (SAW), thin film.skiptabldblfloatfix.

Experimental study on acoustic signal characteristic analysis and time delay estimation of pipeline leakage in boilers

Acoustic signal detection technology has significant advantages in detecting the leakage and bursting of heat exchange pipes in boilers. To address the current lack of sound signal data for steam medium leakages and the problem of large errors in the complex sound field environment of power plants, we performed an innovative experimental comparative analysis of leakage acoustic signals under a dual medium of compressed air and steam to provide a reference for detecting leakage acoustic signals. During the experiment, the time and frequency domains were analyzed by changing the pressure of the leakage pipeline and aperture of the leakage hole, and the spectrogram and power spectrum of the leakage acoustic signal were obtained using fast Fourier transform and autocorrelation analysis. The results showed that the signal value of the leakage medium increased with increasing pipeline pressure and leakage aperture and that the energy of the steam leakage acoustic signal was greater than that of compressed air under the same pressure and aperture because of its larger specific heat capacity. In addition, the complete empirical mode decomposition of adaptive noise (CEEMDAN) algorithm was introduced into the denoising decomposition of the leakage sound signal in the furnace, and the average error of the time delay value of the leakage acoustic signal calculated using the CEEMDAN algorithm was observed to be within 5%.

Integrated navigation algorithm for deep-sea AUV based on M-estimation and heavy-tailed noise

This paper presents an integrated navigation algorithm for deep-sea Autonomous Underwater Vehicles (AUVs) based on M-estimation and heavy-tailed noise to solve the problems of inaccurate noise models in traditional navigation algorithms for deep-sea AUVs, significant delays in Ultra-Short Baseline (USBL) acoustic positioning, and the inability to estimate deep-sea ocean currents. The algorithm encompasses four techniques: ①A Strapdown Inertial Navigation Systems (SINS)/USBL integrated navigation algorithm based on M-estimation and heavy-tailed noise models. ②Estimation and compensation of USBL acoustic delay positioning errors. ③Estimation and compensation of steady or slowly varying ocean currents. ④Considering the distance between the submerged vehicle and the center of the earth and the variation of gravity acceleration with depth. The first and second techniques are the innovations of this article, which can effectively improve the USBL calibration accuracy with only a slight increase in computational complexity. The significant positioning error caused by long-term voyages of large-depth AUVs in the middle layer of the ocean can be effectively suppressed using the third and fourth technologies. The results of the semi-physical simulation and lake experiment demonstrate the ability of the proposed algorithm to significantly improve navigation accuracy and robustness in complex underwater environments compared to conventional methods.

Биосенсор на основе пленки Ленгмюра-Блоджетт с ферментом алкогольоксидазы

The work examined the sensor properties of a biofilm based on phospholipid molecules 1,2-dipalmitoyl-sn-glycero-3-phosphoethanolamine with immobilized molecules of the enzyme alcohol oxidase to vapors of ethyl and isopropyl alcohols. The immobilization of alcohol oxidase enzyme molecules was carried out using a Langmuir monolayer process of phospholipid molecules. The sensor coating was obtained using the Langmuir-Schaeffer technology, in which the substrate is oriented parallel to the monolayer. The analysis of microimages of the film surface obtained by atomic force microscopy, allows to present of enzyme molecules in it was established. The study of the sensory properties of the formed coatings was carried out using acoustoelectronic technology. The presence of the enzyme in the sensor coating led to an increase in the amplitude and phase responses of the acoustic delay line when interacting with vapors of the detected substance. The maximum amplitude and phase responses were recorded when the film interacted with ethanol vapor and were 1.5 dB and 19°, respectively. The work showed that the formed sensor coating has selective sensitivity to ethanol vapor. This allows us to conclude that it is possible to use this sensor coating to create an acoustoelectronic ethanol biosensor. Increasing the sensitivity of such biosensors can be achieved by varying technological parameters such as the number of layers in the film, as well as the amount of immobilized enzyme in each layer.

Adaptive Varying Contention Window MAC Protocol Based on Underwater Acoustic Propagation Delay

Underwater acoustic wave propagation time delay and fluctuations are much greater than radio waves. However, many of the protocols used for underwater acoustic networking and communication are designed according to the principles of terrestrial wireless communication networks, failing to give full consideration to utilizing the underwater acoustic propagation and its time delay variation. For this reason, this paper proposes an adaptive varying contention window MAC (AVCW-MAC) protocol based on propagation delay. The protocol uses AVCW random backoff mechanism to differently set up the contention window (CW) of each node based on the different propagation delays from each underwater sensor node to the cluster head node to improve the channel utilization. In addition, to avoid excessive difference in the CW of each node, the backoff factors <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">K</i> <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">1</sub> and <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">K</i> <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> are introduced in the AVCW random backoff mechanism to improve the fairness of nodes’ accessing the channel. Simulation results show that for the same amount of sensor nodes, the AVCW-MAC protocol have significantly improved network throughput and decreased average end-to-end latency when compared to legacy CW-MAC protocols.

Acousto-electric measurements at 2.5 GHz on graphene transferred onto YX128°-LiNbO3

Surface acoustic wave delay lines with an operational frequency of 2.5 GHz have been designed to measure the acousto-electric transport of carriers in graphene transferred onto YX128°-LiNbO3 piezoelectric substrate. The monolayer of graphene on LiNbO3 presented sheet resistance in the range of 733–1230 Ω/□ and ohmic contact resistance with gold of 1880 to 5200 Ωμm. The measurements with different interaction lengths on graphene bars have allowed the extraction of carrier absorption and mobility parameters from acousto-electric current. Graphene presented higher acousto-electronic interaction in the GHz range than previously reported values in the range of 100s MHz with carrier absorption losses of 109 m−1 and mobility for acoustically generated charges of 101 cm2V−1s−1.

Cognitive perception of biosonar echo delay, phase, and spectrum

FM echolocating big brown bats combine the acoustic delay, phase, and spectrum of echoes into a unitary cognitive attribute of perceived delay. In this talk, we will present psychophysical, neurophysiological, and modeling data showing how this might be accomplished. Delay accuracy measured psychophysically approximates coherent matched-filter accuracy. Psychophysical curves of echo-delay resemble pulse-echo crosscorrelation functions, with phase manifested directly within 20 μs. Computational modeling shows that low-pass time-frequency bandpass filtering at 10 kHz enables the contribution from phase. Neural responses from the auditory midbrain are phase-sensitive for tone-burst offsets up to15 kHz. Echo spectrum (spectral nulls and ripples) is transformed into psychophysical percepts of delay. The external-ear spectral null creates an elevation-dependent peak at about 35 μs for vertical target tracking. Off-axis clutter masking is suppressed by a Gestalt-like normalization process that operates within delay percepts. The organization of perceived delay and the appearance of phase shifts is facilitated by delay processing that begins at the low-frequency tail end of FM sweeps and the linking of 1st and 2nd harmonic frequencies. Surprisingly, this result requires the entire echo to be received before any delay is determined. The implications of this result will be discussed. [Work supported by ONR.]

Features of the Formation of Sensitive Films Based on Mycelium of Higher Fungi for Surface and Plate Acoustic Waves Gas Sensors.

A comparative analysis of the responses of two types of acoustic waves (surface SAW and plate APW) with close frequencies and the same type of waves (SAW) with different frequencies toward various liquid vapors (water, acetone, ethanol) was carried out in this paper. Two types of films based on mycelium of higher fungus Ganoderma lucidum (Curtis) P. Karst (G. lucidum) prepared by various methods were used as sensitive coatings. These films were based on G. lucidum mycelium ethanolic (48% v/v) homogenizate (MEGl) and extract (EGl). A film deposition procedure compatible with acoustic devices technology was developed. Various piezoelectric substrates (YX-LiNbO3, 128 YX-LiNbO3) were used for appropriate acoustic delay lines production. It was found that additional SAW and APW attenuation associated with the appearance of mycelium films on the surface of the acoustic waveguide is two times greater for MEGL than for EGL films in the frequency range of 20-80 MHz The changes in acoustic wave amplitude and phase due to vapor absorption were measured and compared with each other, taking into account the differences in geometry of the samples. It was found that the phase response of the SAW delay lines with EGL films is three times higher than one with the presence of MEGL films for water and ethanol vapors. The films used are demonstrated good reproducibility and long-term stability for at least 2 months. Based on the results obtained, it was concluded that MEGl film is not appropriate for use in high frequency SAW delay lines as a sensitive coating. However, both types of the films (MEGl and EGl) could be used as sensitive coatings for low frequency SAW and APW sensors based on corresponding delay lines. Additionally, it was found that the films used are not sensitive to acetone vapor. As a result of the work carried out, a technique for creating sensitive films based on the mycelium of higher fungi compatible with the planar technology of acoustoelectronic delay lines was developed. The possibility of using such films for the development of gas SAW and APW sensors was shown.

DNoiseNet: Deep learning-based feedback active noise control in various noisy environments

The use of active noise control/cancelation (ANC) has increased because of the availability of efficient circuits and computational power. However, most ANC systems are based on traditional linear filters with limited efficiency due to the highly nonlinear and nonstationary nature of various noises. This paper proposes an advanced deep learning–based feedback ANC named DNoiseNet that overcomes the limitations of traditional ANCs and addresses primary and secondary path effects, including acoustic delay. Mathematical operators (i.e., atrous convolution, pointwise convolution, nonlinear activation filters, and recurrent neural networks) learn multilevel temporal features under different noises in various environments, such as construction sites, vehicle interiors, and airplane cockpits. Due to the nature of feedback control using a single error sensor, an estimation of the reference noise signal must be regenerated. In this paper, a multilayer perceptron (MLP) neural network–based secondary path estimator is also proposed to improve the performance of DNoiseNet. In extensive parametric and comparative studies, the DNoiseNet with the MLP secondary path estimator exhibited the best performance in root mean square error and noise attenuation metrics.

Gigahertz Acoustic Delay Lines in Lithium Niobate on Silicon Carbide With Propagation-Q of 11174

This work demonstrates gigahertz wideband acoustic delay lines (ADLs) with record-breaking propagation-Q using a thin-film X-cut lithium niobate on silicon carbide (LiNbO3-on-SiC) platform. Benefiting from the high bulk wave velocity and excellent mechanical <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\text{f}\times \text{Q}$ </tex-math></inline-formula> of SiC, the shear horizontal surface acoustic wave (SH-SAW) excited by unidirectional transducers propagates in the top-surface of LiNbO3-on-SiC with low acoustic loss. The zero power flow angle (PFA) of −3° to +Y axis is obtained through simulation analysis and experiment validation, which leads to acoustic wave transmission perpendicular to the electrodes. Oriented at zero PFA, the fabricated ADLs show scalable center frequencies from 1.19 GHz to 2.11 GHz, 3-dB fractional bandwidth ranging from 2.7% to 11.5%, and a record-high propagation-Q of 11174. The performance has shown the great potential of the LiNbO3-on-SiC acoustic platform for various signal processing applications.

High-Data-Rate Long-Range Underwater Communications via Acoustic Reconfigurable Intelligent Surfaces

Despite decades-long development, underwater communication systems still cannot achieve high data rates and long communication ranges at the same time (i.e., beyond 1 Mb/s and 1 km). Currently, acoustic communication is the only choice to achieve long distances. However, the inherent low acoustic bandwidth results in extremely low data rates. In this article, the acoustic reconfigurable intelligent surface (RIS) system is proposed to realize high-data-rate long-range underwater communications. Although the EM-based RIS has been widely investigated in terrestrial scenarios in recent years, the underwater acoustic RIS is based on completely different physics principles. Hence, the EM-based terrestrial RISs do not work for underwater acoustic signals. More-over, the long acoustic wave propagation delay, the inherent wideband nature, and the water behavior all impose unique challenges in underwater RIS operation. Therefore, this article presents a new hardware design to realize acoustic RIS, based on which the underwater RIS operation protocols are developed to address the aforementioned challenges. The proposed acoustic RIS system can be considered as an underwater infrastructure that enables beamforming functionalities for all types of devices, especially small robots and low-cost sensors. The simulation results show that the proposed acoustic RIS system can efficiently reflect acoustic waves and dramatically increase communication data rates and distances.

Expansion of beam width in exposure and crystal structure beamline (BL09) of SAGA-LS and applications using expanded beams

In this study, for high-efficiency experiments of deep X-ray lithography, radiation mutation breeding, and X-ray topography, we expanded the beam width in the exposure and crystal structure beamline (BL09) using a synchrotron beam at the SAGA Light Source facility. BL09 was divided into a straight A-line for hard X-rays and a branch B-line for soft X-rays; however, we reconstructed the new BL09 as a single straight-line by unifying the A and B-lines. Vacuum components, such as a large beam shutter, large beryllium window, acoustic delay line, and monochromator chamber were newly located in the reconstructed BL09. A white (or monochromatic) beam can be switched by removing (or inserting) the monochromator into the beam path as needed. After the reconstruction, the widths of the white and monochromatic beams at the terminal of BL09 were expanded from 110 to 395 mm and from 70 to 128 mm, respectively. The expanded white beam has the width of the world-class in synchrotron radiation facilities. Furthermore, we demonstrated the effect of the expanded beams and improvement in the experimental efficiency through deep X-ray lithography, radiation mutation breeding, and X-ray topography. The use of expanded beams is also expected to lead to the fabrication of practicable fine-structures and provide a deeper understanding of defect structures.

Equivalent Circuit Models for SAW Delay Line Sensors

Surface acoustic wave (SAW) devices are widely used as high quality factor filters for telecommunications. In recent years they have been investigated as sensors, which calls for application-specific electronic systems that interact with them. To design such circuits, it is important to understand the peculiarities of the devices, which may be a barrier for system designers. In this work, we explore different models that can be simulated in any circuit simulation environment, facilitating the creation of systems that interact with SAW delay lines, devices in which a signal is delayed by a constant time between piezoelectric transducers. The equivalent circuits of acoustic delay lines can be divided in two categories: a lumped-element model, based on frequency-dependent impedances implemented through the Foster and Mittag-Leffler theorems, and a distributed-element model, based on transmission lines. We compare qualitative frequency and time-domain characteristics among these categories so their limitations are clear, with the lumped-element model not being usable in the time domain due to its singularity at the center frequency. We also describe the process of implementation to achieve the model, while proposing a simple circuit block that can be included to represent perturbations on the device, which allows adjusting of the model response to different perturbations. Our model is also suitable for tests in distinct liquid media, provided that the parallel capacitor is fitted accordingly to model the electromagnetic wave induced in the device.

Low Loss Al0.7Sc0.3N Thin Film Acoustic Delay Lines

reports novel aluminum scandium nitride (Al <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0.7</sub> Sc <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0.3</sub> N) thin film acoustic delay lines (ADLs). Low loss ADLs are implemented on sputtered Al <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0.7</sub> Sc <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0.3</sub> N thin film using cross-field excited single-phase unidirectional transducers (SPUDT), which generate S0 mode Lamb wave between two ports. ADLs are fabricated with up to 300 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\mu \text{m}$ </tex-math></inline-formula> flat delay gap by optimized low stress Al <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0.7</sub> Sc <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0.3</sub> N thin film. A large electromechanical coupling factor ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$K^{ {2}}$ </tex-math></inline-formula> ) of 7.8% provided by approximately 1 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\mu \text{m}$ </tex-math></inline-formula> Al <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0.7</sub> Sc <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0.3</sub> N thin film allows for an overall improvement. Compared to implemented aluminum nitride (AlN) thin film counterparts, Al <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0.7</sub> Sc <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0.3</sub> N ADLs achieve remarkably lower insertion loss (IL), wide fractional bandwidth (FBW), and better impedance matching, featuring a minimum IL of 2.27 dB and a 3-dB FBW of 7.1% at approximately 780 MHz. The increase in relative permittivity due to Sc doping reduces the imaginary part of the matched network by 40%. For fundamental symmetric (S0) Lamb waves, a high group velocity of 8532 m/s, a propagation loss of 0.07 dB/ <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$ {\lambda }$ </tex-math></inline-formula> , and a propagation quality factor (Q) of 338 are extracted. Upon further development, scandium (Sc) doped AlScN thin films could enable CMOS-compatible piezoelectric acoustic platform for signal processing, sensing, and computing applications.

Design and Optimization of a Novel SAW Gyroscope Structure Based on Amplitude Modulation with 1-D Phononic Crystals.

Surface acoustic wave gyroscopes (SAWGs), as a kind of all-solid-state micro-electro-mechanical system (MEMS) gyroscopes, can work normally under extremely high-impact environmental conditions. Among the current SAWGs, amplitude-modulated gyroscopes (AMGs) are all based on the same gyro effect, which was proved weak, and their sensitivity and intensity of the output are both lower than frequency-modulated gyroscopes (FMGs). However, because FMGs need to process a series of frequency signals, their signal processing and circuits are far less straightforward and simple than AMGs. In order to own both high-sensitivity and simple signal processing, a novel surface acoustic traveling wave gyroscope based on amplitude modulation is proposed, using one-dimensional phononic crystals (PCs) in this paper. In view of its specific structure, the proposed gyroscope consists of a surface acoustic wave oscillator and a surface acoustic wave delay line within a one-dimensional phononic crystal with a high-Q defect mode. In this paper, the working principle is analyzed theoretically through the partial wave method (PWM), and the gyroscopes with different numbers of PCs are also designed and studied by using the finite element method (FEM) and multiphysics simulation. The research results demonstrate that under a 1 V oscillator voltage output, the higher sensitivity of −23.1 mV·(rad/s)−1 in the linear range from −8 rad/s to 8 rad/s is reached when the gyro with three PC walls, and the wider linear range from −15 rad/s to 17.5 rad/s with the sensitivity of −6.7 mV·(rad/s)−1 with only one PC wall. Compared with the existing AMGs using metal dots to enhance the gyro effect, the sensitivity of the proposed gyro is increased by 15 to 112 times, and the linear range is increased by 4.6 to 186 times, even without the enhancement of the metal dots.