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为解决声表面波(SAW)湿度传感器存在易被污染、不易清洁、稳定性差等问题,提出了一种新的基于改进的单端口SAW谐振器结构用于湿度检测。在此结构中,在ITO材料制作的叉指换能器和反射阵上溅射厚度为5pm Si3N4层以屏蔽各种腐蚀性物质如酸性、碱性等腐蚀性气体对SAW谐振器电极的侵蚀。相比常规谐振器,新结构加大了谐振器叉指换能器与一个反射阵之间距用于涂敷湿敏材料,同时在石英基片背面布设ITO材料脱湿电路。给出了基于此类结构SAW湿度传感器的制作工艺、感湿实验测试结果。实验验证了该结构SAW湿度传感器的可清洁性、耐腐蚀性及该结构的有效性。 相似文献
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Andrii BuvailoAuthor Vitae Yangjun XingAuthor VitaeJacqueline HinesAuthor Vitae Eric BorguetAuthor Vitae 《Sensors and actuators. B, Chemical》2011,156(1):444-449
Polyvinyl alcohol (PVA) and polyvinyl pyrrolidone (PVP) thin films, deposited on the surface of glass slides, were studied using transmission FTIR spectroscopy upon varying relative humidity (RH) from 2 to 70%. The obtained data revealed fast dynamics of water vapor adsorption-desorption with responses on the order of several seconds. Based on the fast FTIR signal intensity changes versus RH, it was proposed that a similar rapid response can be achieved for PVA and PVP coated SAW devices due to changes in mass-loading and film viscoelastic properties upon absorption of water vapor in the films. Sub-micron thickness films were spin-coated onto the surface of LiNbO3 SAW substrates. Both PVA and PVP based humidity sensors revealed prompt reversible response to variations in humidity, although PVP-based device demonstrated better sensor parameters with total insertion loss variation of about 50 dB over the studied RH range and response time 1.5 s for the humidity step 5-95% (recovery time - 2.5 s), representing one of the fastest SAW-based humidity sensors reported to date. 相似文献
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Studies on a surface acoustic wave (SAW) dosimeter sensor for organophosphorous nerve agents 总被引:1,自引:0,他引:1
As a follow-up of previous work on a Surface Acoustic Wave (SAW) sensor for nerve agents, irreversible response effects have been studied in more detail. Surface analytical studies indicated that degradation products are responsible for the effects observed. In addition it was tried to explore these effects for the development of a nerve agent dosimeter. Experiments were conducted to test the performance of a SAW sensor coated with La(III) 2-bis(carboxymethyl)amino hexadecanoic acid. The experiments revealed that many improvements must be made especially with respect to sensitivity and linear response behaviour. 相似文献
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采用微扰理论分析了覆盖聚合物敏感膜的水平剪切型声表面波气体传感器(SH-SAW)的响应机理。以针对有机磷毒剂具有良好选择性的含氟多羟基聚硅氧烷(FPOL)膜材料为例,分析了聚合物膜厚以及传感器工作频率在敏感膜吸附气体时对传感器响应的影响。计算结果表明,SH-SAW气体传感器对于不同浓度的甲基磷酸二甲酯(DMMP)气体响应随FPOL膜厚和传感器工作频率的改变呈现非线性变化。为了获得线性特性的传感器响应及较小的声波衰减,在一定的DMMP气体浓度检测范围内,通过理论计算提取出了优化的FPOL敏感膜膜厚和传感器工作频率等参数。 相似文献
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传统的电容式湿度传感器采用感湿膜都是水蒸汽通过上表面扩散的长方体感湿膜,因上表面面积有限,且有一部分被上电极覆盖,影响了系统的响应时间。采用了水蒸汽从周围扩散的圆柱体、圆环体结构,将其与传统的长方体做了比较,并在分析圆环体时引入的占空因子k,最后,将电容归一化得出圆柱体的响应时间约为长方体的10倍,圆环体与圆柱体相比,响应时间可减少约77.2%,大大缩短了响应时间,且圆柱体与圆环体对与薄膜厚度没有特别要求,因而还可以减小器件体积。 相似文献
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《微型机与应用》2016,(24):84-86
基于声表面波(SAW)理论以及SAW谐振器的结构和工作原理,设计了一种基于声表面波(SAW)谐振式压力传感器。采用有限元软件COMSOL Multiphysics对ZnO单晶声表面波谐振器进行建模和仿真,提出符合声表面波振型的对称模态和反对称模态,计算出ZnO单晶的相速度为3 237.31 m/s。讨论了ZnO基底厚度对此压力传感器的相速度的影响,得出ZnO基底厚度越大,相速度越小。最后通过加载0~1 000 kg/m~2的质量块来模拟不同的压力对器件的频率响应的影响,结果显示压力的变化与谐振频率二者具有良好的负相关线性关系。通过拟合得出线性表达式。 相似文献
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基于声表面波(SAW)技术的化学毒剂传感器在检测下限、响应速度以及减小温度、湿度交叉敏感等方面还需进一步提高。提出了在SAW双端口谐振器上涂敷超支化聚合物的方法提高传感器的检测下限和灵敏度。通过建立Van Dyke模型,分析了敏感膜对SAW化学毒剂传感器Q值、插入损耗以及电路阻抗匹配的影响。利用谐振器代替延迟线,确保了器件具有插入损耗、高Q值的特点。实验证实,在谐振器的中心栅结构上涂覆聚合物可以减小粘弹性聚合物对谐振器插损、Q值以及输入输出阻抗的影响。对设计的化学毒剂传感器进行了沙林毒剂检测实验,采用315MHz的SAW谐振器结合超支化聚合物膜,检测沙林气体浓度为5.0mg/m^3。实验表明:这种传感器的灵敏度可达到600Hz/mg/m^3,响应时间为50s,恢复时间约为60s。 相似文献
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Highly sensitive humidity sensor at low humidity based on the quaternized polypyrrole composite film
Polypyrrole composite was fabricated by using chemical polymerization at room temperature, which was further quaternized with 1,4-bromobutane to prepare the humidity sensitive material. The electrical properties of the sensor were measured. The results showed that the quaternized polypyrrole composite film exhibited low impedance at very low humidity; the impedance value was about 780 kΩ at 11% RH and the impedance changed from 106 to 103 Ω between 11% and 95% RH, which was suitable for detection of low humidity. Moreover, the logarithm of impedance of the polypyrrole composite film varied linearly (R2 = 0.9916) with relative humidity in the range of 11–95% RH. Surface and cross-sectional morphology of the films, response–recovery time and hysteresis were also measured and estimated. The sensing mechanism of the sensor was also investigated. 相似文献
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The power consumption of a surface acoustic wave (SAW) sensor system was investigated using ANSYS and PSPICE. Simulation results show that several design parameters of the surface acoustic wave sensor, such as the center distance between two interdigital transducers (IDT), the thickness of the piezoelectric substrate, the finger space of the IDT, etc., can greatly affect the power consumption of the whole system. The results of this study will be helpful to optimum design and fabricate the SAW sensor systems with very low-power consumption. 相似文献