Resource Allocation for IRS Assistedmm Wave Wireless Powered Sensor Networks with User Cooperation

In this paper,we investigate IRS-aided user cooperation(UC)scheme in millimeter wave(mmWave)wirelesspowered sensor networks(WPSN),where two single-antenna users are wireless powered in the wireless energy transfer(WET)phase first and then cooperatively transmit information to a hybrid access point(AP)in the wireless information transmission(WIT)phase,following which the IRS is deployed to enhance the system performance of theWET andWIT.We maximized the weighted sum-rate problem by jointly optimizing the transmit time slots,power allocations,and the phase shifts of the IRS.Due to the non-convexity of the original problem,a semidefinite programming relaxation-based approach is proposed to convert the formulated problem to a convex optimization framework,which can obtain the optimal global solution.Simulation results demonstrate that the weighted sum throughput of the proposed UC scheme outperforms the non-UC scheme whether equipped with IRS or not.

GRADIENT SURFACE PLY MODEL OF SH WAVE PROPAGATION IN SAW SENSORS

Investigation of the propagation of the wave in SAW sensors is a basis for the research and design of the sensors. With the advance of the sensor, both the effect of environment on the surface ply and the geometry of waveguide are complicated. To consider the complication, a model with gradient surface ply and multilayer waveguide of SH wave propagation in sensor is proposed. The equation of wave velocity is derived by a transfer matrix method. Through the equation, the function of wave velocity increment via the change of parameters in the surface ply is obtained. The effect of the inhomogeneity on the function is also studied. Finally, some influencing factors of the behavior of the sensor are discussed.

基于软件无线电方案无线无源SAW温度阅读器设计

目前谐振型声表面波(SAW)阅读器射频电路大多采取分立器件设计,针对系统整体工作频段受限,硬件设计繁琐的问题,该文提出了一种软件无线电方案。软件无线电系统主体由ZYNQ和AD9361组成,射频收发端口添加LNA、PA进行信号功率放大,使用射频开关隔离收发。通过发射步进频率5 kHz、带宽1 MHz扫频信号,并对回波进行频谱分析求取最大值,最终得到谐振频率。针对SAW传感器回波持续时间较短而导致FFT计算分辨率的不足,使用重复采集增加数据长度,将阅读器的分辨率提高到468.75 Hz。实验结果表明,该阅读器能够正确探测传感器温度变化。

A novel method for simulating nuclear explosion with chemical explosion to form an approximate plane wave: Field test and numerical simulation

A nuclear explosion in the rock mass medium can produce strong shock waves,seismic shocks,and other destructive effects,which can cause extreme damage to the underground protection infrastructures.With the increase in nuclear explosion power,underground protection engineering enabled by explosion-proof impact theory and technology ushered in a new challenge.This paper proposes to simulate nuclear explosion tests with on-site chemical explosion tests in the form of multi-hole explosions.First,the mechanism of using multi-hole simultaneous blasting to simulate a nuclear explosion to generate approximate plane waves was analyzed.The plane pressure curve at the vault of the underground protective tunnel under the action of the multi-hole simultaneous blasting was then obtained using the impact test in the rock mass at the site.According to the peak pressure at the vault plane,it was divided into three regions:the stress superposition region,the superposition region after surface reflection,and the approximate plane stress wave zone.A numerical simulation approach was developed using PFC and FLAC to study the peak particle velocity in the surrounding rock of the underground protective cave under the action of multi-hole blasting.The time-history curves of pressure and peak pressure partition obtained by the on-site multi-hole simultaneous blasting test and numerical simulation were compared and analyzed,to verify the correctness and rationality of the formation of an approximate plane wave in the simulated nuclear explosion.This comparison and analysis also provided a theoretical foundation and some research ideas for the ensuing study on the impact of a nuclear explosion.

Parametric study on contact sensors for MASW measurement-based interfacial debonding detection for SCCS

Steel-concrete composite structures(SCCS)have been widely used as primary load-bearing components in large-scale civil infrastructures.As the basis of the co-working ability of steel plate and concrete,the bonding status plays an essential role in guaranteeing the structural performance of SCCS.Accordingly,efficient non-destructive testing(NDT)on interfacial debondings in SCCS has become a prominent research area.Multi-channel analysis of surface waves(MASW)has been validated as an effective NDT technique for interfacial debonding detection for SCCS.However,the feasibility of MASW must be validated using experimental measurements.This study establishes a high-frequency data synchronous acquisition system with 32 channels to perform comparative verification experiments in depth.First,the current sensing approaches for high-frequency vibration and stress waves are summarized.Secondly,three types of contact sensors,namely,piezoelectric lead-zirconate-titanate(PZT)patches,accelerometers,and ultrasonic transducers,are selected for MASW measurement.Then,the selection and optimization of the force hammer head are performed.Comparative experiments are carried out for the optimal selection of ultrasonic transducers,PZT patches,and accelerometers for MASW measurement.In addition,the influence of different pasting methods on the output signal of the sensor array is discussed.Experimental results indicate that optimized PZT patches,acceleration sensors,and ultrasonic transducers can provide efficient data acquisition for MASW-based non-destructive experiments.The research findings in this study lay a solid foundation for analyzing the recognition accuracy of contact MASW measurement using different sensor arrays.

离子束刻蚀技术在SAW滤波器频率修整上的应用

随着声表面波(SAW)滤波器的应用向高频、窄带方向延伸,在制造过程中准确地控制其中心频率及一致性变得越来越困难,需要对SAW滤波器的频率进行微调。重点介绍了一种在SAW滤波器上可实现目标频率修整的离子束刻蚀修频工艺,通过实验发现刻蚀厚度不同对滤波器表面的影响程度不同,一次离子束刻蚀厚度为50 nm时,铝膜表面出现微结构变化。分析了对晶圆、器件进行离子刻蚀工艺引起热损伤的机理,表征了不同刻蚀厚度对SAW滤波器粘接芯片的剪切力和硅铝丝键合力的影响。根据实验现象及结果提出了分梯度多次刻蚀的优化方案,给出了不同刻蚀厚度的刻蚀精度,对实验结果进行拟合,得到中心频率与刻蚀厚度的关系方程,从频率、插入损耗和通带方面分析了离子束刻蚀工艺对SAW滤波器电学性能的影响。经离子束刻蚀修频后,滤波器中心频率提高2 MHz,中心频率标准差由0.4 MHz减少为0.15 MHz,中心频率的均一性由0.29%改善至0.11%,频率一致性变好。

Al_(2)O_(3)厚度对SAW传感器声波模式及性能的影响

该文采用多物理场耦合的有限元模型,探究了保护层Al_(2)O_(3)厚度对以LGS为压电基底、Pt为电极的声表面波(SAW)高温传感器中声波特性及器件性能的影响。结果表明,随着Al_(2)O_(3)保护层厚度的增加,声表面波在L波方向的振动位移增加,在SH波和SV波方向的振动位移减弱,当保护层归一化厚度为6.25%时,其能量向衬底内部扩散;当保护层归一化厚度为18.75%时,Rayleigh波消失,此时为体波BAW模式;增加Al_(2)O_(3)保护层,波速v、机电耦合系数K^(2)显著升高;一阶频率温度系数τ_(f,1)和转换温度随保护层厚度的增加而升高。利用Al_(2)O_(3)薄膜对SAW温度传感器进行结构优化,为了获得良好的综合性能,归一化厚度应该在0.94%附近。

结构参数对SAW传感器的影响及电极失效分析

文中通过实验制备了一种以LiNbO_(3)为压电基底,Pt为电极,SiO_(2)为保护层的单端口谐振型声表面波传感器,探究了IDT与反射栅之间的距离Lg和电极宽度对SAW传感器的影响,揭示了不同温度下电极的微观变化规律,结果表明:当L_(g)=λ/2时,SAW传感器可以激发1个稳定的谐振峰,寄生峰对其影响较小;当L_(g)=3λ/8时,可以激发2个稳定的谐振峰;随着电极宽度的增加,声表面波传感器的波速和温度敏感性降低;700℃时,电极的部分结构开始变窄,随着温度的升高,电极和保护层凝聚收缩形成微小的孔洞,当温度达到950~1000℃时,电极熔化失效。

Effect of sensor quantity on measurement accuracy of log inner defects by using stress wave

Wood nondestructive testing （NDT） is one of the high efficient methods in utilizing wood. This paper explained the principle of log defect testing by using stress wave, and analyzed the effects of sensor quantity on defect testing results by using stress wave in terms of image fitting degree and error rate. The results showed that for logs with diameter ranging from 20 to 40 cm, at least 12 sensors were needed to meet the requirement which ensure a high testing accuracy of roughly 90% of fitness with 0.1 of error rate. And 10 sensors were recommended to judge the possible locations of defects and 6 sensors were sufficient to decide whether there were defects or not.

Possibility of the Application of the Ultra-long Electromagnetic Wave Remote Sensor to Marine Geological Exploration

The ultra-long electromagnetic wave remote sensing technique developed by Peking University is one of new future techniques, which can detect the submarine geological information from the depth of 20 to 10000 m below the surface by receiving natural ultra-long electromagnetic waves (n Hz to n 100 Hz). The new remote sensor is composed of three parts: a main instrument with a portable computer, an antenna with an amplifier and an external power.

Hydrogen and Ozone SAW Based Gas Sensors with RF Magnetron Sputtered InO_x and Electron Beam Evaporated SiN_y

Layered Surface Acoustic Wave (SAW) devices with an InO_x/SiN_u/36°YX LiTaO_3 structure were investigated for sensing low concentrations of hydrogen (H_2) and ozone (O_3) at different operating temperatures.The sensor consists of a 1μm thick silicon nitride (SiN_y) intermediate layer deposited by electron beam evaporation on a 36°Y-cut X-propagating piezoelectric lithium tantalate (LiTaO_3) substrate and a 100 nm thin indium oxide (InO_x) sensing layer deposited by R.F.magnetron sputtering.The device fabrication is described and the performance of the sensor is analyzed in terms of response magnitude as a function of operating temperature.Large frequency shifts of 360 kHz for 600μg/g of H_2 and 92 kHz for 40 ng/g O_3 were recorded.In addition,the surface morphology of the deposited films were investigated by Atomic Force Microscopy (AFM) and the chemical composition by X-Ray Photoelectron Spectroscopy (XPS) to correlate gas-sensing behavior to structural characteristics of the thin film.

Transparent ZnO/glass surface acoustic wave based high performance ultraviolet light sensors

Surface acoustic wave （SAW） resonators are a type of ultraviolet （UV） light sensors with high sensitivity, and they have been extensively studied. Transparent SAW devices are very useful and can be developed into various sensors and microfluidics for sensing/monitoring and lab-on-chip applications. We report the fabrication of high sensitivity SAW UV sensors based on piezoelectric （PE） ZnO thin films deposited on glass substrates. The sensors were fabricated and their performances against the post-deposition annealing condition were investigated. It was found that the UV-light sensitivity is improved by more than one order of magnitude after annealing. The frequency response increases significantly and the response becomes much faster. The optimized devices also show a small temperature coefficient of frequency and excellent repeatability and stability, demonstrating its potential for UV-light sensing application.

Piezoelectric Actuator/Sensor Wave Propagation Based Nondestructive Active Monitoring Method of Concrete Structures

In order to monitor the basic mechanical properties and interior damage of concrete structures,the piezoelectric actuator/sensor based wave propagation method was investigated experimentally in the laboratory using a specifically designed test setup.The energy attenuation of stress waves was measured by the relative index between the output voltage of sensors and the excitation voltage at the actuator.Based on the experimental results of concrete cube and cylinder specimens,the effect of excitation frequencies,excitation amplitude,wave propagation paths and the curing age on the output signals of sensors are evaluated.The results show that the relative voltage attenuation coefficient RVAC is an effective indicator for measuring the attenuation of stress waves through the interior of concrete.

Wireless and batteryless SAW sensors,a promising solution for harsh environments

In this paper,general principle of the Surface Acoustic Wave(SAW) sensor in wired and wireless con-figurations will be developed and a review of recent works concerning the field of high temperature applications will be presented.The first part will be devoted to aspects of data transmission and processing.Both configurations of SAW de-vice,delay line and resonator,will be discussed as well as the remote interrogation techniques used to collect and to proc-ess signal.The second part will be devoted to the material aspects.Indeed,knowing that the conventional piezoelectric substrates such as quartz or lithium niobate cannot be used at high temperature,the choice of the material constituting the SAW device(substrate & electrodes) is one of the challenges to face.We will focus our discussion on the Langasite,the current reference for high temperature applications,and on the AlN/Sapphire structure,the very promising alternative for application where the use of high frequency is required.

Surface Acoustic Wave Humidity Sensors Based on(1120) ZnO Piezoelectric Films Sputtered on R-Sapphire Substrates

ZnO films on R-sapphire substrates are prepared and characterized by x-ray diffraction and scanning electron microscopy, which indicate that the thin films are well crystallized with （1120） texture. Love wave and Rayleigh wave are used for fabrications of humidity sensors, which are excited in [1100] and [0001] directions of the （1120） ZnO piezoelectric films, respectively. The experimental results show that both kinds of sensors have good humidity response and repeatability, and the performances of the Love wave sensors are better than those of the Rayleigh wave sensors at room temperature. Moreover, the theoretical calculations of the mass sensitivity of the sensors are a/so carried out and the calculated results are in good agreement with the experimental measurements.

Modeling of wireless SAW temperature sensor and associated antenna

Surface acoustic wave(SAW)resonator used as wireless sensor was characterized and the parameters of its MBVD(Modified Butterworth-Van Dyke)model were extracted versus temperature.The extracted parameters lead toevaluate the resonator performancesin terms of Temperature coefficient of frequency(TCF)and quality factor(Q).An antenna was then associated with the SAW resonator and the entire system has been characterized and modeled.The good agreement experiment-simulation allows to define the optimum operating conditions of the wireless sensor.

Viscoelastic Analysis of a Surface Acoustic Wave Gas Sensor Coated by a New Deposition Technique

与聚合物涂的声学的波浪传感器基于新涂层免职(自我装配、分子地印的技术) 拍摄的表面的反应的分析被描述，反应公式因此被推出。用真实部分砍模量，聚合物能被分类进三种类型：玻璃质的电影，玻璃质似橡胶的电影和似橡胶的电影。试验性的结果比在马丁的理论，而是速度反应不确切与计算一致的证明变细反应在有模拟的更好的坚固性。也许，它被试验性的方法和环境影响。另外，为聚合物电影的煤气的吸着的模拟被执行。，至于玻璃质似橡胶的电影和似橡胶的电影至于玻璃质的电影，有增加电影厚度的锯传感器反应增加，和在传感器反应和气体的集中之间的关系是相当线性的，在传感器敏感和气体的集中之间的关系是很复杂的。最终计算的结果显示在传感器反应和频率之间的关系不由于聚合物的粘弹性的性质总是是线性的。

Effect of Fluid Electrical Property Changes on Surface Transverse Wave Sensors

A fluid sensor based on the surface transverse wave (STW) delay line on ST-cut quartz has been developed and tested in a large number of fluids with different viscosity and permittivity levels.Influence of fluid mechanical and electrical properties on the sensor's response has been determined and the sensor's performance has been compared with a bulk acoustic wave (BAW) viscosity sensor.The result shows that the viscosity sensitivity of the developed STW sensor represented by the signal to noise ratio is lower than that of a 5 MHz BAW sensor.Applications of the sensor in detecting the quality of industrial fluids are discussed.

Strain transfer mechanism of passive wireless surface acoustic wave torque sensors using shear lag theory

A shear-lag theory was developed to investigate the strain transfer from the metal substrate to the surface acoustic wave （SAW） resonator through a bonding layer. A three-layer model of host structure-adhesive layer-resonator layer was established. The strain transfer was theoretically analyzed, and the main factors impacting the SAW sensor measurement were studied. The relationship between the sensor response and the individual effect of all these factors under static loads was discussed. Results showed that better accuracy could be achieved with increase in the adhesive stiffness or resonator length, or decrease in the adhesive thickness. The values of the strain transfer rate calculated from the analytical model agreed well with that from the available experiment data.

Development of A Surface Acoustic Wave LB Membrane Immunity Sensor

Summary: A new kind of biosensor for immunology was developed by ultrasonic technique and LB membrane. A double delay-line resonator was made by using ST-cut quartz crystal with working frequency of 149. 7 MHz. Then a layer of LB membrane was covered on it. When anti-IgM anti- body of various concentrations was added to it, the sensor can be used to detect IgM antigen. The biosensor was highly sensitive, small and light. The experimental results showed that the working frequency change of the sensor was proportional to the concentration of antibody with its dilution ratio between 1: 10000 and 1: 100. It was also first observed that the frequency curve of the sen- sor resulting from the reaction of IgM antigen and antibody undulated in the experiment.