Acoustic Wave Technology Research Articles

Advances in Hybrid Icing and Frosting Protection Strategies for Optics, Lens, and Photonics in Cold Environments Using Thin‐Film Acoustic Waves

Fogging, icing, or frosting on optical lenses, optics/photonics, windshields, vehicle/airplane windows, and solar panel surfaces have often shown serious safety concerns with hazardous conditions and impaired sight. Various active techniques, such as resistive heating, and passive techniques, such as icephobic treatments, are widely employed for their prevention and elimination. However, these methods are not always suitable, effective, or efficient. This review provides a comprehensive overview of the fundamentals and recent advances of transparent thin‐film surface acoustic wave (SAW) technologies on glass substrates for monitoring and prevention/elimination of fogging, frosting, and icing. Key challenges related to fogging and icing on glass substrates are discussed, along with fundamental mechanisms that establish thin‐film SAWs as optimal solution for these issues. Various types of thin‐film acoustic wave technologies are discussed, including recent wearable and flexible SAW devices integrated onto glass substrates for expanding future applications. The focus of this review is on the principles and strategies for hybrid or integrated de‐fogging/de‐icing and sensing/monitoring functions. Finally, critical issues and future outlooks for thin‐film‐based SAW technology on glass substrates in industry applications are presented.

An Algorithm for Synthesizing Groups of Codes in an RFID Multiple Access System

Relevance. One of the problems that must be solved when creating RFID systems is the reader's multiple access to a group of tags located in a limited space, since the reading signal causes a one-time response of many tags, which leads to collisions (conflicts) of response signals. This problem has not been solved in relation to passive tags without a chip, based on surface acoustic wave technologies, the code of which is laid down during manufacture and cannot be changed during operation. The purpose of the study is to develop algorithms that allow synthesizing such groups of codes that would provide a controlled level of pairwise correlation of the selected label signals and thereby ensure the specified accuracy of label identification. The proposed algorithms are based on the procedures of code concatenation and inductive construction of groups of codes with a given volume and correlation level. For the algorithm for forming a group of codes with the required value of the correlation coefficient and the algorithm for combining groups of codes into complete and maximum groups, properties have been proven that confirm the possibility of using them to formulate tasks for preparing groups of labels on surfactants that would correspond to the number of objects requiring identification and the accuracy of their identification and taking into account the number of labels in the group, the conditions for the propagation of radio signals in the area of operation of the reader, the number of repeated readings of the label codes, as well as algorithms for joint data processing, received with all calculations.The methods used. Methods of coding theory and correlation analysis. Result. The developed algorithm is a tool for creating modern coding systems for surfactant labels. The scientific novelty. Well-known algorithms for multiple access in RFID systems are proposed in the GEN1 and GEN2 EPC Global standards, and assume that the tag has a chip and a power supply, which makes it possible to implement protocols for influencing the tag with a reader using special commands. The proposed multiple access algorithm is applicable for passive surfactant tags, including those moving at high speed and/or located in aggressive environments, since the tags do not use silicon technology compared to active RFID tags. Practical significance. The use of the proposed set of algorithms will increase the efficiency of marking systems by reducing the identification time of objects located in a confined space.

Comprehensive overview of detection mechanisms for toxic gases based on surface acoustic wave technology

Identification and detection of toxic/explosive environmental gases are of paramount importance to various sectors such as oil/gas industries, defense, industrial processing, and civilian security. Surface acoustic wave (SAW)-based gas sensors have recently gained significant attention, owing to their desirable sensitivity, fast response/recovery time, wireless capabilities, and reliability. For detecting various types of targeted gases, SAW sensors with different device structures and sensitive materials have been developed with diversified working mechanisms. This paper is focused on overviewing recent advances in working mechanisms and theories of dominant sensitive materials and key mechanisms/principles for targeting various gases in the realm of SAW gas sensors. The basic sensing theories and parameters of SAW gas sensors are briefly discussed, and then the major influencing factors are systematically reviewed, including the effects of various sensitive layer materials, temperature/humidity, and UV illumination on the overall performance of SAW gas sensors. We further highlight the relationships and adsorption/desorption principles between sensing materials and key targeted gases, including NH3, NO2, H2S, explosive gases of H2, and 2,4,6-trinitrotoluene, and organic gases of isopropanol, ethanol, and acetone, as well as others gases of CO, SO2, and HCl. Finally, we discuss key challenges and future outlooks in designing methodologies of sensing materials and enhancing the performance of SAW gas sensors, offering fundamental guidance for developing SAW gas sensors with good sensing performance.

High electromechanical coupling factor Lamb wave resonator

Lamb wave resonators (LWRs) based on lithium niobate on insulator (LNOI) substrates operating in an A1 mode at frequencies above 5 GHz typically exhibit high electromechanical coupling coefficients (K2) ranging from 20% to 30%. This makes them promising candidates to replace current bulk acoustic wave technology in next-generation broadband RF filters. However, the K2 of conventional LWRs still struggles to meet application requirements for bandwidths exceeding 1 GHz, such as WiFi-6E. This paper presents an analytical optimization approach for rapid and comprehensive scanning of the full 3D Euler space to find the maximum effective K2 of LWR devices. Such a full scan is difficult to achieve by the conventional time-consuming finite element method (FEM). The K2 results for a selected subset of Euler angles obtained through this analytical approach align with FEM simulation results. The optimized results show that LWRs on LNOI can achieve the highest K2 of 59.92% at Euler angles of (0, −151°, −60°), providing bandwidths exceeding 1 GHz at 5 GHz. To validate this optimization approach, LWRs with various orientations were fabricated on both 41° YX-cut and Z-cut LNOI wafers, with measured K2 values at different Euler angles agreeing well with both analytical and FEM results. The proposed K2 optimization method serves as a valuable guideline for selecting substrate cuts and device orientations in the design of ultra-broadband filters for next-generation telecommunications.

Wireless Powered Surface Acoustic Wave Platform for Achieving Integrated Functions of Fogging/Icing Protection and Monitoring.

In this study, we introduced an integrated approach using piezoelectric thin film-based surface acoustic wave (SAW) and wireless power transfer (WPT) technologies, designed for both passive monitoring and active defogging/icing functions. We systematically investigated the resonant frequency shifts of ZnO/glass SAW devices, establishing their correlations with variations in humidity and temperature under cold conditions. Acoustic waves generated through the ZnO/glass SAW device were used for defogging and deicing functions with effects of RF powers and acousto-heating thoroughly evaluated. More significantly, the WPT system was successfully applied for achieving defogging and deicing functions, with its performance comparable to that of conventional wired SAW systems. Our findings demonstrated that the WPT SAW system significantly minimizes localized acousto-heating effects, although the time taken for both defogging and deicing was slightly longer than the wired system. This work represents a significant advancement in developing multifunctional, optically compatible, and wireless-integrated solutions for SAW based ice protection.

Surface acoustic wave platform integrated with ultraviolet activated rGO-SnS2 nanocomposites to achieve ppb-level dimethyl methylphosphonate detection at room-temperature

Dimethyl methylphosphonate (DMMP) is commonly used as an alternative for demonstrating to detect sarin, which is one of the most toxic but odorless chemical nerve agents. Among various types of DMMP sensors, those utilizing surface acoustic wave (SAW) technology provide notable advantages such as wireless/passive monitoring, digital output, and a compact, portable design. However, key challenges for SAW-based DMMP sensors operated at room temperature lies in simultaneous enhancement of sensitivities and reduction of detection limits. In this study, we developed a binary material strategy by combining reduced graphene oxide (rGO) and tin disulfide (SnS2) with (100)-facets orientation as sensing layers of SAW device for DMMP detection utilized at room temperature. Ultraviolet (UV) light was applied to activate the sensitive film and reduce the sensor's response time. The developed SAW DMMP sensor demonstrated a superior sensitivity (−1298.82 Hz/ppm), a low detection limit of 50 ppb, and a hysteresis below 1.5%, along with fast response/recovery time (39.2 s/28.4 s), excellent selectivity, long-term stability and repeatability. The formation of shrub-like rGO-SnS2 heterojunctions with abundant surface defects and large specific surface areas, high-energy (100) crystalline surfaces of SnS2, and photogenerated carriers generated by UV irradiation were pinpointed as the crucial sensing mechanisms. These factors collectively enhanced adsorption and reaction dynamics of DMMP molecules.

Bulk acoustic wave—Solidly mounted resonator with a-SiOCN:H as low-Z material

Bulk acoustic wave (BAW) filters have been proven to be of high demand in today's low power RF front-ends for mobile communication devices. Within the launch of 5G applications worldwide, especially in the region of new radio (nr-1) up to 6 GHz, defined frequency bands require filters of wide bandwidths, while simultaneously featuring steep edges and high out-of-band rejection. Due to the coexistence with 4G LTE (long term evolution) wireless standards as well as advanced data transfer concepts such as carrier aggregation, the increasing complexity of antenna systems forces the implementation of highly selective acoustic filters. In contrast to the widely used surface acoustic wave (SAW) technology, BAW filters appear with superior performance for frequencies above 1 GHz. This work describes the fabrication of a BAW-solidly mounted resonator (BAW-SMR) with a tailored material system of a-SiOCN:H as a low impedance (low-Z) material integrated within its acoustic Bragg mirror. A direct comparison to the widely used low-Z material of SiO2 with an acoustic impedance of around 13 MRayl is demonstrated by two equal resonator stacks by replacing only the uppermost low-Z thin film of the acoustic reflector. A single-mask design was chosen with platinum as a bottom electrode to ensure the most equal growth conditions for the piezoelectric aluminum nitride (AlN) layers on both reflectors’ surfaces featuring either the tailored a-SiOCN:H or standard SiO2. The a-SiOCN:H thin films were deposited by plasma-enhanced chemical vapor deposition and the according acoustic impedance was priorly depicted to 7.1 MRayl, which could be exploited to achieve an increase in the effective coupling coefficient beyond 7% as well as a resonator bandwidth of more than 60 MHz.

Response Patterns of Acoustic Wave Characteristics to Reservoir Petrophysical Parameters in Different Bedding Directions: A Case Study of Low- and Middle-Rank Coals in Xinjiang, China.

The physical properties of coal reservoirs, important parameters for evaluating the production potential of coalbed methane (CBM) resources, can be assessed nondestructively and in real-time using acoustic wave technology. In this study, we collected 48 low- and middle-rank coal samples oriented in different bedding directions from seven typical coal mines, encompassing the Zhunan, Tuha, and Kuqa-Bay coalfields in Xinjiang, China. We clarified the characteristics of the physical parameters (apparent density, fracture, porosity, and permeability) and acoustic wave of coal variations through acoustic wave, porosity, and permeability experiments, revealing the response law of acoustic wave characteristics to the physical parameters of coal. The results indicated that the acoustic wave velocity and dynamic elastic modulus (E d) of coal samples oriented in the perpendicular bedding direction are larger than those oriented in the parallel bedding direction; however, the dynamic Poisson's ratio (μd) of coal samples oriented in different bedding directions does not significantly differ. The existence of fractures significantly reduces the acoustic wave velocity and E d of the coal. The greater the apparent density of coal, the tighter its structure, resulting in a faster acoustic wave velocity. The larger the porosity of coal, the greater its internal voids, leading to a more pronounced attenuation of acoustic energy and a slower acoustic wave velocity. The more developed and interconnected the bedding fractures of coal bodies oriented in the parallel bedding direction, the higher their permeability, resulting in a smaller decrease in acoustic wave velocity. Conversely, the more developed the bedding fractures of coal bodies oriented in the perpendicular bedding direction, the more pronounced their attenuation of acoustic wave velocity. Finally, the regression equations for E d with the square of P-wave velocity (V P 2) and μd with the square ratio of V P to S-wave velocity (V P 2/V S 2) were established for coal. The study findings can help evaluate and predict the reservoir quality of coal seams, assess CBM, and improve the safety and efficiency of its extraction.

Flexible surface acoustic wave technology for enhancing transdermal drug delivery.

Transdermal drug delivery provides therapeutic benefits over enteric or injection delivery because its transdermal routes provide more consistent concentrations of drug and avoid issues of drugs affecting kidneys and liver functions. Many technologies have been evaluated to enhance drug delivery through the relatively impervious epidermal layer of the skin. However, precise delivery of large hydrophilic molecules is still a great challenge even though microneedles or other energized (such as electrical, thermal, or ultrasonic) patches have been used, which are often difficult to be integrated into small wearable devices. This study developed a flexible surface acoustic wave (SAW) patch platform to facilitate transdermal delivery of macromolecules with fluorescein isothiocyanates up to 2000kDa. Two surrogates of human skin were used to evaluate SAW based energized devices, i.e., delivering dextran through agarose gels and across stratum corneum of pig skin into the epidermis. Results showed that the 2000kDa fluorescent molecules have been delivered up to 1.1mm in agarose gel, and the fluorescent molecules from 4 to 2000kDa have been delivered up to 100µm and 25µm in porcine skin tissue, respectively. Mechanical agitation, localised streaming, and acousto-thermal effect generated on the skin surface were identified as the main mechanisms for promoting drug transdermal transportation, although micro/nanoscale acoustic cavitation induced by SAWs could also have its contribution. SAW enhanced transdermal drug delivery is dependent on the combined effects of wave frequency and intensity, duration of applied acoustic waves, temperature, and drug molecules molecular weights.

Achieving consistency of flexible surface acoustic wave sensors with artificial intelligence

Flexible surface acoustic wave technology has garnered significant attention for wearable electronics and sensing applications. However, the mechanical strains induced by random deformation of these flexible SAWs during sensing often significantly alter the specific sensing signals, causing critical issues such as inconsistency of the sensing results on a curved/flexible surface. To address this challenge, we first developed high-performance AlScN piezoelectric film-based flexible SAW sensors, investigated their response characteristics both theoretically and experimentally under various bending strains and UV illumination conditions, and achieved a high UV sensitivity of 1.71 KHz/(mW/cm²). To ensure reliable and consistent UV detection and eliminate the interference of bending strain on SAW sensors, we proposed using key features within the response signals of a single flexible SAW device to establish a regression model based on machine learning algorithms for precise UV detection under dynamic strain disturbances, successfully decoupling the interference of bending strain from target UV detection. The results indicate that under strain interferences from 0 to 1160 με the model based on the extreme gradient boosting algorithm exhibits optimal UV prediction performance. As a demonstration for practical applications, flexible SAW sensors were adhered to four different locations on spacecraft model surfaces, including flat and three curved surfaces with radii of curvature of 14.5, 11.5, and 5.8 cm. These flexible SAW sensors demonstrated high reliability and consistency in terms of UV sensing performance under random bending conditions, with results consistent with those on a flat surface.

Research on particle separation microfluidic chip based on standing surface acoustic wave

Microparticle and cell separation is a key process in the study of cell properties, clinical diagnosis and disease treatment. In this paper, a particle separation method based on the combination of surface acoustic wave and microfluidic technology is proposed, which uses standing surface acoustic wave to achieve the separating of polystyrene microparticles of different sizes twice in a continuous flow. Through numerical simulation of the device model and particle trajectory simulation, the optimum particle separation parameters were determined. The particle separation microfluidic chip has successfully realized the particle separation. The separation yield of 5 μm particles is about 92.1%. The separation rate of 1 μm particles is about 83.3%.

Evaluation of a novel, sensitive thyroid-stimulating hormone assay as a diagnostic test for thyroid disease in cats.

Clinicians commonly use thyroid-stimulating hormone (TSH) concentrations to diagnose thyroid disorders in humans and dogs. In cats, canine TSH chemiluminescent immunoassays (CLIA) assays are commonly used to measure TSH, but these TSH-CLIAs cannot measure low TSH concentrations (< 0.03 ng/mL) and therefore cannot distinguish between low-normal concentrations and truly low TSH concentrations (characteristic of hyperthyroidism). Our aim was to evaluate a novel TSH assay based on bulk acoustic wave (BAW) technology that has lower functional sensitivity (0.008 ng/mL) than TSH-CLIAs. 169 untreated hyperthyroid cats, 53 cats treated with radioiodine (131I), 12 cats with chronic kidney disease (CKD), and 78 clinically healthy cats. Serum concentrations of T4, TSH-CLIA, and TSH-BAW were measured in all cats. Untreated hyperthyroid cats were divided into 4 severity groups (subclinical, mild, moderate, and severe), whereas 131I-treated cats were divided into euthyroid and hypothyroid groups. Test sensitivity, specificity, and positive predictive value for identifying hyperthyroidism were higher for TSH-BAW (90.5%, 98.9%, and 86.9%) than TSH-CLIA (79.9%, 76.7%, and 21.7%; P < .001). Test sensitivity for identifying 131I-induced hypothyroidism was only 45.5% for T4 versus 100.0% for both TSH-CLIA and TSH-BAW (P = .03), whereas TSH-BAW had a higher positive predictive value (100%) than did either TSH-CLIA (81.2%) or T4 (71.9%). Serum TSH-BAW alone or together with T4 is a highly sensitive and specific diagnostic test for evaluating feline hyperthyroidism and iatrogenic hypothyroidism. Finding low serum TSH-BAW concentrations is most useful for diagnosing subclinical and mild hyperthyroidism, in which serum T4 remains within or only slightly above the reference interval.

New Advances in Rapid Pretreatment for Small Dense LDL Cholesterol Measurement Using Shear Horizontal Surface Acoustic Wave (SH-SAW) Technology.

Atherosclerosis is an inflammatory disease of the arteries associated with alterations in lipid and other metabolism and is a major cause of cardiovascular disease (CVD). LDL consists of several subclasses with different sizes, densities, and physicochemical compositions. Small dense LDL (sd-LDL) is a subclass of LDL. There is growing evidence that sd-LDL-C is associated with CVD risk, metabolic dysregulation, and several pathophysiological processes. In this study, we present a straightforward membrane device filtration method that can be performed with simple laboratory methods to directly determine sd-LDL in serum without the need for specialized equipment. The method consists of three steps: first, the precipitation of lipoproteins with magnesium harpin; second, the collection of effluent from a 100 nm filter; and third, the quantification of sd-LDL-ApoB in the effluent with an SH-SAW biosensor. There was a good correlation between ApoB values obtained using the centrifugation (y = 1.0411x + 12.96, r = 0.82, n = 20) and filtration (y = 1.0633x + 15.13, r = 0.88, n = 20) methods and commercially available sd-LDL-C assay values. In addition to the filtrate method, there was also a close correlation between sd-LDL-C and ELISA assay values (y = 1.0483x - 4489, r = 0.88, n = 20). The filtration treatment method also showed a high correlation with LDL subfractions and NMR spectra ApoB measurements (y = 2.4846x + 4.637, r = 0.89, n = 20). The presence of sd-LDL-ApoB in the effluent was also confirmed by ELISA assay. These results suggest that this filtration method is a simple and promising pretreatment for use with the SH-SAW biosensor as a rapid in vitro diagnostic (IVD) method for predicting sd-LDL concentrations. Overall, we propose a very sensitive and specific SH-SAW biosensor with the ApoB antibody in its sensitive region to monitor sd-LDL levels by employing a simple delay-time phase shifted SH-SAW device. In conclusion, based on the demonstration of our study, the SH-SAW biosensor could be a strong candidate for the future measurement of sd-LDL.

Aerosol jet printing of surface acoustic wave microfluidic devices

The addition of surface acoustic wave (SAW) technologies to microfluidics has greatly advanced lab-on-a-chip applications due to their unique and powerful attributes, including high-precision manipulation, versatility, integrability, biocompatibility, contactless nature, and rapid actuation. However, the development of SAW microfluidic devices is limited by complex and time-consuming micro/nanofabrication techniques and access to cleanroom facilities for multistep photolithography and vacuum-based processing. To simplify the fabrication of SAW microfluidic devices with customizable dimensions and functions, we utilized the additive manufacturing technique of aerosol jet printing. We successfully fabricated customized SAW microfluidic devices of varying materials, including silver nanowires, graphene, and poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS). To characterize and compare the acoustic actuation performance of these aerosol jet printed SAW microfluidic devices with their cleanroom-fabricated counterparts, the wave displacements and resonant frequencies of the different fabricated devices were directly measured through scanning laser Doppler vibrometry. Finally, to exhibit the capability of the aerosol jet printed devices for lab-on-a-chip applications, we successfully conducted acoustic streaming and particle concentration experiments. Overall, we demonstrated a novel solution-based, direct-write, single-step, cleanroom-free additive manufacturing technique to rapidly develop SAW microfluidic devices that shows viability for applications in the fields of biology, chemistry, engineering, and medicine.

Doped tungsten oxide microstructures for enhancing ultraviolet sensing based on ZnO/glass transparent acoustic wave technology

Doped tungsten oxide microstructures for enhancing ultraviolet sensing based on ZnO/glass transparent acoustic wave technology

MXene-activated graphene oxide enhancing NO2 capture and detection of surface acoustic wave sensors

Surface acoustic wave (SAW) technology has been widely used in the field of harmful gas detection, but there remain a lot of challenges, such as long response/recovery time as well as poor selectivity and repeatability. Herein, we activate graphene oxide (GO) using MXene with excellent adsorption capacity (MXene/GO) to realize efficient NO2 gas detection. The SAW sensor assembled with the multilayered MXene/GO composite showcases an enhanced gas sensing performance to the NO2 gas (1–200 ppm) enabling high sensitivity (Δf=260 Hz/ppm), fast response/recovery time, excellent selectivity, and good repeatability at room temperature. The enhanced high sensitivity and selectivity detection of NO2 gas is attributed to the large pore size, hydrophilicity, and abundant surface functional groups of the multilayered MXene/GO composite. This elaborate design is expected to propel the development of next-generation acoustic gas phase sensors.

Research and experiment the wireless passive surface acoustic wave technology for conductor temperature monitoring of high voltage equipment

This paper presents the research and design of a passive thermal monitoring system using wireless temperature sensors based on the principle of surface acoustic wave (SAW). The monitoring system is employed on components that need to be monitored for heat generation, including switch contacts, busbars, and cable connections at switchgears or ring main units (RMUs). The basic impulse insulation level (BIL), or voltage spike tolerance, of the wireless SAW temperature sensor utilised in this study, means that it is not necessary to power it with sensors that meet the high criteria for equipment installed in closed cabinets or medium voltage cabinets. The research team’s activities in this study included software development, data transmission design and manufacture, and sensor selection. The system functions steadily, with a temperature error of no more than 2oC, according to the test findings under laboratory settings.

A High-Performance Weighing Sensor Based on Surface Acoustic Wave Technology

A High-Performance Weighing Sensor Based on Surface Acoustic Wave Technology

Acoustofluidic patterning in glass capillaries using travelling acoustic waves based on thin film flexible platform

Surface acoustic wave (SAW) technology has been widely used to manipulate microparticles and biological species, based on acoustic radiation force (ARF) and drag force induced by acoustic streaming, either by standing SAWs (SSAWs) or travelling SAWs (TSAWs). These acoustofluidic patterning functions can be achieved within a polymer chamber or a glass capillary with various cross-sections positioned along the wave propagating paths. In this paper, we demonstrated that microparticles can be aligned, patterned, and concentrated within both circular and rectangular glass capillaries using TSAWs based on a piezoelectric thin film acoustic wave platform. The glass capillary was placed at different angles along with the interdigital transducer directions. We systematically investigated effects of tilting angles and wave characteristics using numerical simulations in both circular and square shaped capillaries, and the patterning mechanisms were discussed and compared with those agitated under the SSAWs. We then experimentally verified the particle patterns within different glass capillaries using thin film ZnO SAW devices on aluminum (Al) sheets. Results show that the propagating SAWs can generate acoustic pressures and patterns in the fluid due to the diffractive effects, drag forces and ARF, as functions of the SAW device’s resonant frequency and tilting angle. We demonstrated potential applications using this multiplexing, integrated, and flexible thin film-based platform, including patterning particles (1) inside multiple and successively positioned circular tubes; (2) inside a solidified hydrogel in the glass capillary; and (3) by wrapping a flexible ZnO/Al SAW device around the glass capillary.

Проект IEEE oral history: академик Ю. В. Гуляев. Часть 4

The article is a fragment of an interview taken by Academician Yu. V. Gulyaev by the IEEE History Center in Gorgier, Switzerland, July 13, 2017. Of the 14 interview sections, the article presents the following two: Future developments in the field of acoustic wave technology and Friends and awards. The article eliminated bibliographic inconsistencies. The purpose of the report is to familiarize in this part of the profile Russian-speaking community with the main provisions of the interview.