共查询到20条相似文献,搜索用时 31 毫秒
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Rongjun Cheng Yulong Zhao Cun Li Bian Tian Zhongliang Yu Keyin Liu 《Microsystem Technologies》2015,21(3):631-640
A new type of resonant pressure sensor is presented which is realized by combination of a double-ended tuning fork (DETF) quartz resonator and a silicon diaphragm. To examine the feasibility and investigate the performance of this innovation, theoretical analysis and finite elements method are employed to optimize the structure parameters. Micromachining technology are involved in the fabrication of the silicon diaphragm and the DETF quartz resonator, which are fabricated separately and bounded together afterwards. Performances of the sensor prototypes are experimentally investigated. Preliminary testing results demonstrate that the sensor features a high sensitivity of approximately 452.5 Hz/kPa in the operating range of 0–6 kPa at room temperature, with a non-linearity <0.035 % FS and a hysteresis of 0.055 % FS. In addition, the maximum zero-drift is about 0.5 Hz/h which reveals favorable frequency stability. Thus, the feasibility of this scheme is verified. Due to the excellent performances such as high accuracy, high sensitivity, low cost and simple fabrication, this novel resonant sensor provides a commendable solution for low pressure measurement. 相似文献
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H. S. Wasisto S. Merzsch A. Waag I. Kirsch E. Uhde T. Salthammer E. Peiner 《Microsystem Technologies》2012,18(7-8):905-915
A novel MEMS-based cantilever sensor with slender geometry is designed and fabricated to be implemented for determining personal exposure to carbon engineered nanoparticles (NPs). The function principle of the sensor is detecting the cumulative mass of NPs deposited on the cantilever surface as a shift in its resonant frequency. A self-sensing method with an integrated full Wheatstone bridge on the cantilever as a piezoresistive strain gauge is introduced for signal readout replacing optical sensing method. For trapping NPs to the cantilever surface, an electrostatic field is used. The calculated equivalent mass-induced resonant frequency shift due to NPs sampling is measured to be 11.78?±?0.01?ng. The proposed sensor exhibits a mass sensitivity of 8.33?Hz/ng, a quality factor of 1,230.68?±?78.67, and a temperature coefficient of the resonant frequency (TC f ) of ?28.6?ppm/°C. These results and analysis indicate that miniaturized sensors based on self-sensing piezoresistive microcantilever can offer the performance to fulfill the requirements of real-time monitoring of NPs-exposed personnel. 相似文献
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A trapezoidal cantilever density sensor based on MEMS technology 总被引:1,自引:0,他引:1
Li-bo Zhao Long-qi Xu Gui-ming Zhang Yu-long Zhao Xiao-po Wang Zhi-gang Liu Zhuang-de Jiang 《浙江大学学报:C卷英文版》2013,14(4):274-278
A trapezoidal cantilever density sensor is developed based on micro-electro-mechanical systems (MEMS) technology. The sensor measures fluid density through the relationship between the density and the resonant frequency of the cantilever immersed in the fluid. To improve the sensitivity of the sensor, the modal and harmonic response analyses of trapezoidal and rectangular cantilevers are simulated by ANSYS software. The higher the resonant frequency of the cantilever immersed in the fluid, the higher the sensitivity of the sensor; the higher the resonant strain value, the easier the detection of the output signal of the sensor. Based on the results of simulation, the trapezoidal cantilever is selected to measure the densities of dimethyl silicone and toluene at the temperature ranges of 30 to 55 °C and 26 to 34 °C, respectively. Experimental results show that the trapezoidal cantilever density sensor has a good performance. 相似文献
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Resonant Magnetic Field Sensor With Frequency Output 总被引:1,自引:0,他引:1
《Journal of microelectromechanical systems》2006,15(5):1098-1107
This paper presents a novel type of resonant magnetic field sensor exploiting the Lorentz force and providing a frequency output. The mechanical resonator, a cantilever structure, is embedded as the frequency-determining element in an electrical oscillator. By generating an electrical current proportional to the position of the cantilever, a Lorentz force acting like an additional equivalent spring is exerted on the cantilever in the presence of a magnetic field. Thus, the oscillation frequency of the system, which is a function of the resonator's equivalent spring constant, is modulated by the magnetic field to be measured. The resonant magnetic field sensor is fabricated using an industrial CMOS process, followed by a two-mask micromachining sequence to release the cantilever structure. The characterized devices show a sensitivity of 60 kHz/Tesla at their resonance frequency$f_0= 175~ kHz$ and a short-term frequency stability of 0.025 Hz, which corresponds to a resolution below 1$~mu T$ . The devices can thus be used for Earth magnetic field applications, such as an electronic compass. The novel resonant magnetic field sensor benefits from an efficient continuous offset cancellation technique, which consist in evaluating the frequency difference measured with and without excitation current as output signal. 1676 相似文献
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针对硅微谐振式传感器频率测量中精度低的弊端,依据周期测频法原理,设计了一种基于FPGA的测频周期自调整频率计。首先在一个待测信号周期内,对标准信号的上升沿进行计数,粗略计算出待测信号频率和周期。据此对标准信号的上升沿重新计数,从而精确测量出待测信号的频率。测量后的频率信号经过RS-232串行通信接口送入PC上位机,可以实现频率数值的实时显示和储存。测试表明:采用该频率计测量1 Hz~2 MHz方波信号的相对误差可以达到10-7量级。利用该频率计测量谐振式传感器闭环自激测量电路输出的谐振频率信号,频率信号稳定在1 Hz以内。 相似文献
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谐振式光纤陀螺(Resonator Fiber Optic Gyro,RFOG)是基于Sagnac效应产生的谐振频率差来测量旋转角速度的一种新型光学传感器,在小型化和集成化方面具有明显优势。相比于传统的模拟检测技术,数字检测技术具有稳定性好、抗干扰能力强、处理速度快和体积小、易于集成等优势。论文建立了基于单片可编程逻辑器件(Field Programmable Gate Array,FPGA)的数字RFOG系统,在单片FPGA上实现了基于比例积分控制技术的谐振频率伺服回路、用于自动反馈补偿相位调制器由于环境温度等发生变化时引起的2π复位电压漂移问题,以及体现Sagnac频差信号的第二闭环反馈控制回路。最后将研制的基于单片FPGA的闭环数字检测电路应用于实际RFOG系统,顺利验证了上述功能,并实际观测了陀螺转动信号。 相似文献
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电磁激励谐振式MEMS压力传感器闭环控制研究 总被引:1,自引:0,他引:1
在谐振器动力学分析的基础上,系统地比较了谐振式压力传感器检测速度谐振频率和检测位移谐振频率的优缺点.设计出一种零相移的电磁激励谐振式MEMS压力传感器闭环控制系统,该系统利用检测速度谐振频率提高传感器的信号检测稳定性,并且控制电路无需移相环节即可保证传感器在工作频率范围内实现稳定可靠的闭环自激.实验结果表明,采用该闭环控制系统的传感器具有较高的稳定性,传感器长时漂移低于0.025%F.S.,在10 hPa~1 050 hPa范围内非线性度为0.06%. 相似文献
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Michael Stifter Franz Keplinger Harald Steiner Wilfried Hortschitz Thilo Sauter 《Microsystem Technologies》2014,20(4-5):783-791
This paper presents a magnetic field sensor with capacitive read-out, whose active element is a micromachined mechanical resonator. The MEMS magnetic field sensor exploits the Lorentz force to detect external magnetic flux density through the displacement of the resonant structure, which can be measured with optical and capacitive sensing techniques. The micromachined U-shaped cantilever features a length of 2 mm, a base width of 90 μm and a thickness of 20 μm, and is manufactured in SOI technology. The designed sensor has a measured resonant frequency of 4.359 kHz for the fundamental mode and a calculated mass of the flexible structure of 24.5 ng. A quality factor in the order of 104 at an ambient pressure of 0.3 Pa has been measured where a magnetic field resolution of 15 nT can be achieved. Although these arrangements are well suited to capacitively sense the vibrations caused by the Lorentz force on the current lead on the silicon part, care has to be taken to avoid undesired mutual interferences. A serious interference was observed in case of a DC bias voltage at the readout capacitance and a significant voltage drop caused by the current needed for the generation of the Lorentz force. This work investigates in detail this phenomenon as well as the complete physical transduction chain and improves the understanding of such microelectromechanical systems significantly. An analytical model of the electrostatic system is established including all relevant components and their interactions as well as the motion of the MEMS part. The importance of electrostatic back-action for a feasible detection limit for magnetic fields was recognized for the first time. 相似文献
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提出了一种高Q值微陀螺快速锁定谐振频率的方法,可以减小其锁相环的调节时间。该方法基于高Q值微陀螺驱动模态受迫响应的瞬态分量包含谐振频率信息且持续时间长的特点,首先简要介绍了高Q值对锁相环锁定过程的影响,重点分析了其对锁频速度的影响;然后通过理论推导以及系统仿真验证了所提方法的可行性和有效性;最后基于FPGA设计了数字驱动电路,并对高Q值陀螺(Q值约为200000)进行驱动模态谐振频率锁定测试。试验结果表明,该方案可以有效控制压控振荡器(VCO)输出信号频率由初始频率迅速跳频至谐振频率附近,并由锁相环迅速锁定。 相似文献
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Yoshinobu Murakawa Motoaki Hara Hiroyuki Oguchi Yuichiro Hamate Hiroki Kuwano 《Microsystem Technologies》2013,19(8):1255-1259
This paper describes a new type hydrogen sulfide (H2S) gas sensor using ionic liquid (IL). In this sensor, a reservoir for the IL was integrated on a surface acoustic wave (SAW) resonator. The IL serves as an absorber for H2S gas. Mass change due to this absorption is detected as shift in the resonant frequency. In this study, we fabricated and demonstrated the sensor using the lithium niobate (LiNbO3) SAW resonator with the resonant frequency of 38 MHz. The integrated reservoir was filled by the IL 1-butyl-3-methylimidazolium hexafluorophosphate ([bmim]-[PF6]). As an experimental result, we observed the linear correlation between the frequency-shift and the exposure time of the sensor to the H2S gas. 相似文献
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介绍了一种基于新型高阻抗QVBA的高增益谐振电路设计和谐振电路的分析测试实验。利用阻抗分析仪4294A测得石英振梁的等效参数,对石英振梁的电气特性进行分析,发现高阻抗石英振梁起振比普通晶振需要更高增益。基于双门振荡电路,利用运算放大器在开环系统中具有无限增益的理论,提高谐振电路的驱动能力。同时采用谐波抑制网络,指出谐波抑制网络可以抑制无用的频率避免传感器输出信号出现泛音频率,并提高谐振电路的稳频速度。考虑电噪声对输出波形质量的影响,在电路的输入部分采用滤波电容,并在电路的输出部分采用反向器整形,使电路输出标准的方波信号。最后利用安捷伦DSO5012A型号示波器和频率计对高增益谐振电路和石英振梁组成的谐振系统进行测试,测试结果表明本文设计的谐振电路与石英振梁组成的谐振系统可以输出标准的方波信号,输出频率精度达到10-5 kHz,在振动稳定以后频率变化小于0.1 Hz,无泛音频率出现,对研究高精度MEMS加速度计传感器具有重要意义。 相似文献
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提出一种新型的基于基片集成波导和消失模谐振腔的压力传感结构。设计了圆形空腔,当施加外界压力时,圆形空腔发生形变从而使谐振腔谐振频率变化。采用共面波导线对谐振腔进行耦合馈电并将频率信号传输出来。通过读取传感器的回波损耗参数( S11)来表征压力与频率的关系。利用高频仿真软件HFSS对谐振腔进行了仿真设计和优化,设计尺寸为30 mm×30 mm×1.93 mm,与传统谐振腔相比体积明显减小。传感器基底为Rogers 4003C板材,采用PCB技术进行加工。搭建压力测试平台对传感器进行测试,结果表明在0~3 N的压力范围内变化100 MHz,绝对灵敏度为25 MHz/N。仿真和实测结果比较吻合,验证了所设计压力结构的有效性。 相似文献
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The drive axis of a capacitive micro-gyroscope sensor forms an ‘electrical-mechanical’ resonator with closed-loop drive circuits when the gyro is in full operation. The parasitic feed-through capacitance, which exists between the driving and sensing electrodes of the sensor, induces two main negative effects: preventing the expected ‘electrical-mechanical’ oscillation and introducing an undesired high frequency ‘electrical’ oscillation. In this paper, mathematical expression of the critical parasitic feed-through capacitance allowing the occurrence of ‘electrical-mechanical’ oscillation is derived for the first time. Based on the derived expression, a conclusion that increasing the polarization voltage on the sensor mass be the only electrical way to increase the critical value of parasitic feed-through capacitance is revealed. Then with an implemented silicon chip for the drive circuit, the reason of occurring electrical oscillation is analyzed, and an effective solution to avoid the electrical oscillation referred as increasing the polarization voltage is proposed. Experiments on a capacitive micro-gyroscope prototype show that when the polarization voltage is increased from 10 to 18 V, the closed-loop drive circuit eliminates possibility of the electrical oscillation effectively. As a result, the proposed electrical oscillation solution has been verified. 相似文献
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Cheng K.M. Weng Z. Oliver D.R. Thomson D.J. Bridges G.E. 《Journal of microelectromechanical systems》2007,16(5):1054-1060
A noncontact electrostatic probing technique using a scanning probe microscopy cantilever is shown to actuate and detect the resonant behavior of a micromachined resonator. The method is capable of characterizing a resonator with resonant frequency much greater than that of the cantilever. The coupled oscillator model developed for this system describes the resonant response of the test resonator as detected through the probe, including the fourth-power dependence on the probe drive voltage. The veracity of this model is demonstrated through comparison with experimental data obtained from a test resonator with a resonant frequency ten times greater than the resonant frequency of the probe cantilever. This technique yields a straightforward determination of the resonant frequency and quality factor of a micromachined resonator, avoiding limitations due to optical interference and any reliance on a supporting circuitry. 相似文献
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设计了一种静电激励/电容检测的硅微机械谐振压力传感器,采用改进的侧向动平衡双端固支音叉谐振器,利用基于绝缘体上硅的加工工艺制作。为了抑制压力敏感膜片受压变形时谐振器的高度变化,在谐振器固定端设计了全新的桁架结构。针对传感器检测信号微弱和同频干扰严重的特点,在芯体和接口电路设计中采取添加屏蔽电极、降低交流驱动电压幅值、差动电容检测和高频载波调制解调方案等多项措施。同时基于该接口电路设计了开环测试系统,并在常压封装条件下对传感器进行了初步性能测试。实验结果表明:其基础谐振频率为33.886 kHz,振动品质因数为1222;测量范围为表压0~280 kPa,非线性为0.018%FS,迟滞为0.176%FS,重复性为0.213%FS;在-20~60℃的温度范围内,谐振器的平均温度漂移为-0.037%/℃。 相似文献
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Masoud Baghelani Habib Badri Ghavifekr Afshin Ebrahimi 《Microsystem Technologies》2013,19(7):1087-1095
This paper presents an analytical evaluation of the previously demonstrated Ring Shape Anchored Contour Mode Disk (RSACMD) resonator and extracts its equivalent electrical circuit. In the next step, a series resonant Pierce oscillator is designed and parameterized based on the calculated MEMS characteristics. Due to the inherent 180° of phase shift in the RSACMD resonator equivalent circuit, a modified version of a Pierce sustaining circuit is introduced with two inverters (instead of one inverter in conventional Pierce oscillators) to compensate that extra phase shift and satisfy Barkhausen criteria. The designed circuit presents excellent phase noise performance because of a special design which results in small frequency pulling and enable the circuit oscillate close to natural frequency of the high Q resonator. The overall circuit consumes less than 257 μW from a 1.8 V power supply. 相似文献