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Pspice Equivalent Circuit Model for Implementation of Surface Acoustic Wave Filter
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作者 李媛媛 卢文科 +2 位作者 朱长纯 刘君华 蒋华 《Journal of Donghua University(English Edition)》 EI CAS 2012年第2期148-152,共5页
The crystals of quartz,lithium,and piezoelectric ceramics have a piezoelectric effect as their major characteristic.The surface acoustic wave filter(SAWF) was designed by using this property.However,the experimental c... The crystals of quartz,lithium,and piezoelectric ceramics have a piezoelectric effect as their major characteristic.The surface acoustic wave filter(SAWF) was designed by using this property.However,the experimental cost of the fabrication of SAWF is higher than that of mechanical filter or LC filter.Through the RLC(resistor,inductor and capacitor) network equivalent circuit and the interdigital transducer(IDT) equivalent circuit model,the electromotive force,the mechanical impedance of piezoelectric plate,and the wave number of Mason circuit model were researched.The equivalent circuit can be used to reduce product development costs and shorten the development cycle.Comparing simulation result by Pspice software with the theory of SAWF,the simulated waveform is similar to theory measurement,and the equivalent circuit model is verified. 展开更多
关键词 surface acoustic wave filter(SAWF) interdigital transducer(IDT) Mason equivalent circuit Pspice software
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Robust autopilot with wave filter for ship steering
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作者 WANG Xian-zhou XU Han-zhen 《Journal of Marine Science and Application》 2006年第2期24-29,共6页
Research was done to overcome traditional problems associated with automatic steering systems of a ship in a seaway. A ship’s dynamic model with wave disturbances was built and a wave filter was designed by means of ... Research was done to overcome traditional problems associated with automatic steering systems of a ship in a seaway. A ship’s dynamic model with wave disturbances was built and a wave filter was designed by means of an extended states observer (ESO). The model estimated the low frequency motion component from a heading measurement corrupted by colorednoise, so back-and-forth steering caused by high frequency wave disturbances was avoided. At the same time, a robust autopilot system, designed by variable structure control theory, was presented. Simulation results achieved in dangerous sea status show that the wave filter works very well and the autopilot has strong robustness to environmental disturbances and model perturbation, and more importantly, the frequency of rudder adjustments is reduced noticeably. 展开更多
关键词 AUTOPILOT wave disturbances variable structure control wave filter extended states observer (ESO)
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ARBITRARY E-PLANE STRIP DISCONTINUITIES AND THEIR APPLICATION TO MILLIMETER WAVE FILTERS
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作者 戎敖生 李嗣范 《Journal of Electronics(China)》 1990年第2期106-114,共9页
Various E-plane strip discontinuities are analyzed by the moment method and gener-alized network analysis technique.By introducing an idea of waveguide in a wide-sense,the effectsof the thickness of the strips are tak... Various E-plane strip discontinuities are analyzed by the moment method and gener-alized network analysis technique.By introducing an idea of waveguide in a wide-sense,the effectsof the thickness of the strips are taken into account and a unified treatment of such problems isrealized.A set of curves of the equivalent circuit parameters for the discontinuities of E-planestrips are given.Two E-plane bandpass filters are designed at W-band.The experimental resultsagree well with theoretical predietions. 展开更多
关键词 MILLIMETER wave Integrated CIRCUIT filter Equivalent CIRCUIT parameter
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Surface Micromachining of Bulk Acoustic Wave Filters
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作者 赵宏锦 任天令 +3 位作者 丛鹏 刘建设 刘理天 李志坚 《Tsinghua Science and Technology》 SCIE EI CAS 2003年第2期126-129,共4页
The most common typical bulk acoustic wave (BAW) filters are fabricated using bulk micromachining technology, but they have several disadvantages. This paper describes a structure for front end passband BAW filters ma... The most common typical bulk acoustic wave (BAW) filters are fabricated using bulk micromachining technology, but they have several disadvantages. This paper describes a structure for front end passband BAW filters manufactured using surface micromachining. Porous silicon is used as a thick sacrificial layer. The structure reduces the influence of the support film on the filter to improve the VLSI compatibility as well as the filter quality. The cross-talk between resonators with different frequencies can be dramatically reduced by using resonators with a self-supporting structure. 展开更多
关键词 Acoustic waves ETCHING Porous silicon Resonators wave filters
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Using LMS Adaptive Filter in Direct Wave Cancellation 被引量:6
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作者 徐元军 陶然 +1 位作者 王越 单涛 《Journal of Beijing Institute of Technology》 EI CAS 2003年第4期425-427,共3页
The way to use the least-mean-square (LMS) arithmetic to cancel the direct wave for a passive radar system is introduced. The model of the direct wave is deduced. By using the LMS adaptive FIR filter, the software sol... The way to use the least-mean-square (LMS) arithmetic to cancel the direct wave for a passive radar system is introduced. The model of the direct wave is deduced. By using the LMS adaptive FIR filter, the software solution for FM passive radar system is developed instead of the hardware consumption of the existent experiment system of passive radar. Further more some simulative results are given. The simulative results indicate that using LMS arithmetic to cancel the direct wave is effective. 展开更多
关键词 LMS arithmetic adaptive filtering direct wave cancellation
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Simulation of Cellular Neural Networks by Wave Digital Filter Principles
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作者 Guo, Hongxing Yan, Jie +1 位作者 Qing, Lingsong Bao, Zongti 《Wuhan University Journal of Natural Sciences》 EI CAS 1998年第3期69-72,共4页
Based on wave digital filter(WDF) principles, this paper presents a digital model of cellular neural networks(CNNs). The model can precisely simulate the dynamic behavior of CNNs.
关键词 cellular neural networks wave digital filters digital simulation
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Optimized Implementation for Wave Digital Filter Based Circuit Emulation on FPGA
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作者 Yue Ma Shun'an Zhong Shiwei Ren 《Journal of Beijing Institute of Technology》 EI CAS 2017年第2期235-244,共10页
A binary tree representation is designed in this paper for optimization of wave digital filter(WDF)implementation.To achieve this,an equivalent WDF model of the original circuit is converted into abinary tree repres... A binary tree representation is designed in this paper for optimization of wave digital filter(WDF)implementation.To achieve this,an equivalent WDF model of the original circuit is converted into abinary tree representation at first.This WDF binary tree can then be transformed to several topologies with the same implication,since the WDF adaptors have a symmetrical behavior on their ports.Because the WDF implementation is related to field programmable gate array(FPGA)resource usage and the cycle time of emulation,choosing aproper binary tree topology for WDF implementation can help balance the complexity and performance quality of an emulation system.Both WDF-FPGA emulation and HSpice simulation on the same circuit are tested.There is no significant difference between these two simulations.However,in terms of time consumption,the WDF-FPGA emulation has an advantage over the other.Our experiment also demonstrates that the optimized WDF-FPGA emulation has an acceptable accuracy and feasibility. 展开更多
关键词 analog circuit emulation wave digital filter (WDF) field programmable gate array(FPGA)
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DESIGN OF POLYPHASE WAVE DIGITAL FILTERS WITH APPROXIMATELY LINEAR PHASE
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作者 程海 江锡仁 刘小坚 《Journal of Electronics(China)》 1990年第1期62-69,共8页
It is well known that IIR digital filters require quite fewer computations,comparedwith FIR filters,in order to meet stringent magnitude specifications when the phase distortioncan be tolerated.An approximately linear... It is well known that IIR digital filters require quite fewer computations,comparedwith FIR filters,in order to meet stringent magnitude specifications when the phase distortioncan be tolerated.An approximately linear phase,however,can be also obtained with the IIRfilter by making use of a technique without increasing the complexity.Based on a certain numberof attenuation zeros in the pass band,a new approach is developed for the design of polyphasewave digital filters with exact magnitude responses and Chebyshev approximation of the desiredphase responses.The minimum number of attenuation zeros is estimated,and some examples areincluded. 展开更多
关键词 DIGITAL filter wave DIGITAL filter POLYPHASE wave DIGITAL filter
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Polarization Filtering Method for Suppressing Surface Wave in Time-Frequency Domain
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作者 Xiaoming Yang Yang Gao +2 位作者 Wenzhong Zhang Yanchun Wang Meihua Lan 《International Journal of Geosciences》 2019年第4期481-490,共10页
In order to suppress the surface wave in three-component seismic exploration, according to the polarization characteristics of body wave and surface wave, a time-frequency domain polarization filtering method based on... In order to suppress the surface wave in three-component seismic exploration, according to the polarization characteristics of body wave and surface wave, a time-frequency domain polarization filtering method based on wavelet transform was studied. A covariance matrix was constructed in the time-frequency domain for the three-component seismic data, measured the polarization parameters of seismic waves. Combining the corresponding eigenvalues and eigenvectors of the matrix, the elliptic rate and elevation angle were used as constraints, and the polarization filter function was built to separate the surface waves. The separated surface waves were inversely transformed and then were adaptively subtracted from the original records. After the polarization filtering suppressed the surface wave, the signal-to-noise ratio of the converted wave was effectively improved. It laid a good foundation for the next seismic data processing and seismic exploration development. The actual data processing results show that the method can effectively extract surface waves from three-component seismic records and avoid the interference of surface waves on seismic signals. 展开更多
关键词 THREE-COMPONENT SEISMIC Data Surface wave POLARIZATION filterING ADAPTATION
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VDTA-Based Wave Active Filter
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作者 Harshvardhan Singh Kunal Arora Dinesh Prasad 《Circuits and Systems》 2014年第5期124-131,共8页
In this paper we present a wave active filter based on Voltage Differencing Transconductance Amplifiers (VDTAs). The synthesis of active filters basically based on processing of wave quantities. The wave method is pre... In this paper we present a wave active filter based on Voltage Differencing Transconductance Amplifiers (VDTAs). The synthesis of active filters basically based on processing of wave quantities. The wave method is presented for basic building blocks of active filters i.e. a series inductor and parallel capacitor through which realization of various active circuits is made by appropriate connections. The proposed wave active filter is verified by realizing a 4th order low pass Butterworth filter using SPICE simulation with 0.18 μm TSMC CMOS technology parameters. 展开更多
关键词 VOLTAGE Differencing TRANSCONDUCTANCE AMPLIFIER wave Active filter VOLTAGE-MODE filter
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CMOS Realization of VDTA Based Electronically Tunable Wave Active Filter with Minimum Power Consumption at Low Supply Voltage ±0.82 V
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作者 Ghanshyam Singh 《Circuits and Systems》 2020年第2期11-26,共16页
This paper presents a higher order voltage and current mode low pass or high pass filter for wave active filter based on Voltage Differencing Transconductance Amplifiers (VDTAs). The wave equivalent variable technique... This paper presents a higher order voltage and current mode low pass or high pass filter for wave active filter based on Voltage Differencing Transconductance Amplifiers (VDTAs). The wave equivalent variable technique and topological simulation as well as operational realization using wave variables techniques are proposed for basic active building blocks of wave active filters. The proposed wave equivalent technique is employed for wave active filter with the proper selection of the terminal connections. This work presented the basic element for the realizing wave active filter is the series inductor with parallel grounded capacitor. The proposed wave active filter is verified by realizing a 4th order low pass and high pass Butterworth filter with minimum power consumption at ±0.82 V using SPICE simulation with 0.18 μm TSMC CMOS technology parameters. 展开更多
关键词 wave Active filter VOLTAGE Differencing TRANSCONDUCTANCE AMPLIFIER Voltage/Current Mode CMOS Technology
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OBSERVER/FILTER STRUCTURE BASED ADAPTIVE FRICTION COMPENSATION FOR HIGH PRECISION TURNTABLE 被引量:3
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作者 王忠山 苏宝库 王毅 《Transactions of Nanjing University of Aeronautics and Astronautics》 EI 2008年第2期113-120,共8页
Two adaptive friction compensation schemes are developed for a high precision turntable system with nonlinear dynamic friction to handle two types of parametric uncertainties in the friction. Both schemes utilize a no... Two adaptive friction compensation schemes are developed for a high precision turntable system with nonlinear dynamic friction to handle two types of parametric uncertainties in the friction. Both schemes utilize a nonlinear observer/filter structure to compensate for uncertainties in corresponding friction parameters associated with the turntable system. Moreover, in the second scheme, adjustable gains are introduced into the dual nonlin- ear filters and they can be tuned to improve the position tracking performance. In both cases, a Lyapunov-like argument is provided for the global asymptotic stability of the closed-loop system. Simulation results demonstrate the effectiveness of the proposed schemes. 展开更多
关键词 FRICTION wave filters adaptive friction compensation high precision turntable observer/filter structure
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基于环形阵列的空间滤波器结构损伤扫描监测方法研究 被引量:1
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作者 常琦 徐勇 赵恒 《仪器仪表学报》 EI CAS CSCD 北大核心 2024年第1期221-229,共9页
本文提出了一种基于环形阵列的空间滤波器结构损伤扫描监测方法,在结构中央布置环形压电传感器阵列实现对结构的全方位扫描监测,消除了主动Lamb波空间滤波器监测方法中盲区及远场对监测效果的影响。环形阵列由直径方向不同角度的4个线... 本文提出了一种基于环形阵列的空间滤波器结构损伤扫描监测方法,在结构中央布置环形压电传感器阵列实现对结构的全方位扫描监测,消除了主动Lamb波空间滤波器监测方法中盲区及远场对监测效果的影响。环形阵列由直径方向不同角度的4个线阵组成,每个线阵采用主动Lamb波空间滤波监测方法对结构损伤进行监测、成像,各阵列成像结果通过PCA-小波变换进行融合对损伤位置进行判别,从而实现结构全方位损伤扫描监测,消除单个阵列损伤监测的盲区、远场及虚假成像等影响,进而获得更加准确的损伤监测结果。通过实验研究,验证了该方法的有效性和实用性。 展开更多
关键词 LAMB波 空间滤波器 损伤扫描监测 多阵列成像融合
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Directional Filtering Due to Mesospheric Wind Shear on the Propagation of Acoustic-gravity Waves
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作者 YU Yonghui CHEN Wei WANG Yachong 《空间科学学报》 CAS CSCD 北大核心 2013年第1期53-62,共10页
Gravity waves with periods close to the Brunt-V(a|¨)is(a|¨)l(a|¨) period of the upper troposphere are often observed at mesopause altitudes as short period,quasi-monochromatic waves.The assumption that ... Gravity waves with periods close to the Brunt-V(a|¨)is(a|¨)l(a|¨) period of the upper troposphere are often observed at mesopause altitudes as short period,quasi-monochromatic waves.The assumption that these short period waves originate in the troposphere may be problematic because their upward propagation to the mesosphere and lower thermosphere region could be significantly impeded due to an extended region of strong evanescence above the stratopause.To reconcile this apparent paradox,an alternative explanation is proposed in this paper.The inclusion of mean winds and their vertical shears is sufficient to allow certain short period waves to remain internal above the stratopause and to propagate efficiently to higher altitudes.A time-dependent numerical model is used to demonstrate the feasibility of this and to determine the circumstances under which the mesospheric wind shears play a role in the removal and directional filtering of short period gravity waves. Finally this paper concludes that the combination of the height-dependent mean winds and the mean temperature structure probably explains the existence of short period,quasi-monochromatic structures observed in airglow images of mesopause region. 展开更多
关键词 Acoustic-gravity waves Numerical simulation Wind shear Directional filtering
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Adaptive Match-Filtering: A Biomedical Application to Identify T-Wave Alternans
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作者 Laura Burattini Giovanni Ottaviano +1 位作者 Francesco Di Nardo Sandro Fioretti 《Natural Science》 2014年第10期709-718,共10页
T-wave alternans (TWA), consisting in an alternation of the electrocardiographic (ECG) repolarization segment (T-wave), is a promising index of the risk of sudden cardiac death. By definition, it is characterized by a... T-wave alternans (TWA), consisting in an alternation of the electrocardiographic (ECG) repolarization segment (T-wave), is a promising index of the risk of sudden cardiac death. By definition, it is characterized by a frequency component, termed fTWA, that matches half heart rate. The heart-rate adaptive match filter (AMF) based method is a technique for automatic TWA identification from the digital ECG. Aim of the present study was to provide a complete technical description of the filter able to explain its methodological principles. The AMF is usually realized as a 6th order Butterworth filter with a narrow (0.12 Hz) passing band centered in fTWA. It is applied in a bidirectional fashion, so that final filtering order is 12. While extracting the TWA component, the AMF simultaneously filters out every ECG component including noise and artefacts, and thus results are very robust. Goodness of the technique was tested using 8 synthetic ECG tracings corrupted by typical noisy factors, such as white random noise, baseline wanderings, heart-rate variability, and others. Six ECG tracings were affected by 100 μV TWA, whereas two were not. Results indicate that the AMF-based method is able to prevent false-positive and false-negative detections and, thus, represents a useful tool for a reliable TWA identification. 展开更多
关键词 ADAPTIVE filterING Digital ECG T-wave ALTERNANS SUDDEN Cardiac DEATH
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基于5G系统的微带滤波器设计
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作者 王娇 《舰船电子工程》 2024年第6期216-220,共5页
设计了一组具有小波纹特性并且工作在5G附近频段的微波低通滤波器和带通滤波器。采用半集总参数结构,通过与最大平坦度特性比较,选择了滤波特性更加优越的切比雪夫低通原型滤波器,这种类型的滤波器主要采用耦合微带线形式,该文对这种滤... 设计了一组具有小波纹特性并且工作在5G附近频段的微波低通滤波器和带通滤波器。采用半集总参数结构,通过与最大平坦度特性比较,选择了滤波特性更加优越的切比雪夫低通原型滤波器,这种类型的滤波器主要采用耦合微带线形式,该文对这种滤波器设计进行了理论分析并仿真。该实验通过分析计算,并根据实际情况改变了滤波器节数,最终基于ADS软件仿真,将低通滤波器带内最大波纹控制在了-0.383 dB,最高频率为5 GHz;带通滤波器以5.5 GHz为中心频率,通带带宽为1 GHz,带内最大波纹为-2.166 dB。 展开更多
关键词 滤波器 小波纹 半集总参数结构 ADS
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适用于直流保护的数学形态学降噪与噪声干扰识别方法
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作者 薛士敏 张君婷 +1 位作者 李博通 李翔宇 《电力系统保护与控制》 EI CSCD 北大核心 2024年第13期136-148,共13页
柔性直流输电系统是调节我国能源分布不均问题的重要手段,直流保护是保证柔直系统安全的重要技术。现有工程中多采用行波保护作为主保护,然而行波保护存在易受噪声影响、故障波头不易捕捉等问题,制约了其广泛应用。针对上述问题,提出数... 柔性直流输电系统是调节我国能源分布不均问题的重要手段,直流保护是保证柔直系统安全的重要技术。现有工程中多采用行波保护作为主保护,然而行波保护存在易受噪声影响、故障波头不易捕捉等问题,制约了其广泛应用。针对上述问题,提出数学形态学降噪与噪声干扰识别方法,并根据直流保护采样信号特点进行参数设计,用于直流保护采样信号降噪和噪声干扰的识别。首先,确定基于自适应多尺度形态滤波的直流信号降噪方法,并设计结构元素长度和形态学滤波器类型、自适应多尺度形态滤波器的滤波器阶数和步长。其次,确定基于形态学梯度变换的噪声干扰识别方法,并设计形态学梯度变换的阈值。接着,从不同角度对形态学降噪方法与现有典型信号处理方法的滤波效果进行对比分析。最后,对形态学降噪与噪声干扰识别方法和保护的配合效果进行验证。形态学降噪与噪声干扰识别方法所需采样频率较低,运算量适中,滤波效果好,对直流保护适用性好。 展开更多
关键词 行波保护 自适应多尺度形态滤波 噪声干扰识别 形态学梯度 故障波头捕捉
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机器学习的高精度毫米波雷达测距信号误差补偿方法
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作者 李淑玲 姚香秀 张俊丽 《激光杂志》 CAS 北大核心 2024年第8期224-229,共6页
毫米波雷达是一种常用的非接触式测距技术,受环境因素以及测量过程中存在的各种误差影响,测距结果可能存在一定的误差。研究误差补偿方法可以有效提高毫米波雷达的测距精度,从而更准确地获取目标物体的距离信息。为此,提出了机器学习的... 毫米波雷达是一种常用的非接触式测距技术,受环境因素以及测量过程中存在的各种误差影响,测距结果可能存在一定的误差。研究误差补偿方法可以有效提高毫米波雷达的测距精度,从而更准确地获取目标物体的距离信息。为此,提出了机器学习的高精度毫米波雷达测距信号误差补偿方法。通过高斯滤波器去除雷达测距信号中的噪声,完成信号的去噪处理。利用模拟插入脉冲计数法和四象限光斑定位法,测量目标物体的距离和角度信息,通过自适应惯性权重与收敛因子优化粒子群算法,并利用优化后的粒子群算法改进BP神经网络,将测量的距离和角度信息输入到改进的BP神经网络中展开训练,即可得到补偿后的雷达测距信号。实验结果表明,该方法的信号处理效果好,补偿后的毫米波雷达测距信号方位角和俯仰角误差接近于0,且信号平滑度较高。 展开更多
关键词 机器学习 毫米波雷达 误差补偿 高斯滤波器 BP神经网络
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硅基钽酸锂异质晶圆键合工艺研究 被引量:1
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作者 陈哲明 丁雨憧 +3 位作者 邹少红 龙勇 石自彬 马晋毅 《人工晶体学报》 CAS 北大核心 2024年第4期634-640,共7页
5G移动通信的发展对声表面波滤波器提出了高频、小型化、集成化的要求。相较于传统压电体单晶材料,采用硅基压电单晶薄膜材料制备的声表面波滤波器具有高频、低插入损耗、高温稳定性等优势,是高性能声表面波器件发展的核心基础材料。Sma... 5G移动通信的发展对声表面波滤波器提出了高频、小型化、集成化的要求。相较于传统压电体单晶材料,采用硅基压电单晶薄膜材料制备的声表面波滤波器具有高频、低插入损耗、高温稳定性等优势,是高性能声表面波器件发展的核心基础材料。Smart-Cut^(TM)是制备硅基压电单晶薄膜材料的主要方法,键合工艺是其中的核心工序,键合质量决定了硅基压电单晶薄膜晶圆材料的质量,并影响器件性能。本文通过低温直接键合工艺,对等离子活化、兆声清洗、预键合、键合加固四道工序展开优化,最终实现了键合强度高达1.84 J/m^(2)、键合面积超过99.9%的高质量硅基钽酸锂异质晶圆键合。 展开更多
关键词 硅基钽酸锂 低温直接键合 等离子活化 兆声清洗 预键合 键合加固 声表面波滤波器
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特种车辆多维载荷谱加速方法及在振动环境模拟试验中的应用
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作者 韩庆 房强 +1 位作者 范伟光 王帅 《装备环境工程》 CAS 2024年第6期45-52,共8页
目的 解决车辆多轴轴耦合台架试验耗时长、花费大以及振动环境模拟精度低等问题。方法 将雨流投影方法运用到多维载荷加速处理中,利用传统雨流滤波法和多轴雨流投影滤波方法分别对特种车辆部件实际所受的多轴载荷进行加速处理,对加速后... 目的 解决车辆多轴轴耦合台架试验耗时长、花费大以及振动环境模拟精度低等问题。方法 将雨流投影方法运用到多维载荷加速处理中,利用传统雨流滤波法和多轴雨流投影滤波方法分别对特种车辆部件实际所受的多轴载荷进行加速处理,对加速后的多维载荷信号开展基于时域波形再现的振动环境模拟,以更有效地利用轮式车多轴轴耦合试验台开展加速疲劳试验。结果 对比加速前后的多维载荷信号,在时域、频域、损伤域基本一致的前提下,多维载荷信号时间压缩了50%,多轴振动环境的模拟精度大于80%。结论 采用该方法开展车轮加速疲劳试验,能够精确再现被试件的实际振动环境。通过实际试验验证,可以很好地再现故障出现的时间和形式,与实际野外路试结果十分吻合。 展开更多
关键词 加速疲劳试验 多维载荷信号处理 雨流滤波 RP滤波方法 时域波形再现 等效里程
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