【作者】 刘积学；

【导师】 钟先信；

【作者基本信息】 重庆大学 ， 仪器科学与技术， 2008， 博士

【摘要】 传感器技术是信息技术的关键基础,受到广泛重视。声表面波(Surface Acoustic Wave—SAW)传感器是一种以SAW为信息敏感载体的传感器,具有敏感精度高、响应时间快、适用范围宽、体积小等特点,在航空航天、食品卫生、环境监测、医药化工、过程监控、军事安全等领域获得了广泛的应用,特别是在生化微量物质检测方面,SAW传感器显示了独特的技术优点,受到各国军方高度重视,已成为当前战场生化战剂实时检测的首选传感器之一。SAW传感器具有敏感精度高、响应时间快等诸多突出优点,但由于其多参数信息敏感特性,选择性差、抗干扰能力弱已成为SAW传感器无法回避的固有的弱点,在复杂环境条件中,特别是在战场生化战剂实时检测环境中,这些固有的弱点将使SAW传感器的应用受到了极大的限制。因此,解决SAW传感器,特别是SAW生化战剂传感器的选择性、抗干扰等问题,已成为当前SAW传感器研究的热点。自2000年开始,在承担的国家“863”项目“新一代无线通信用SAW器件及材料研究”、国防基础预先研究项目“SAW技术研究”、国防基金项目“SAW化学传感器理论与技术研究”等项目的支持下,针对SAW传感器的选择性、抗干扰能力等问题,论文作者对SAW传感器的选择性、抗干扰能力等问题的理论基础进行了系统和深入的研究,为博士论文的完成奠定了坚实宽广的理论基础和系统深入的专门技术知识。论文从SAW传感器信息敏感基本理论出发,深入解剖SAW传感器信息敏感的物理过程,提出了该过程中信息—信号映射的三个物理过程的划分及其对应的数学表达,建立了SAW传感器信息敏感模型;根据该信息敏感模型,基于SAW振荡器的SAW信号—电信号频率参数映射机理,建立了SAW传感器的信号处理模型;在此基础上,利用SAW阵列信号提供冗余信息的能力,建立了SAW传感器的多参数信息敏感模型和多参数信号处理模型—K矩阵,从而建立了一套基于多参数信息敏感和识别的SAW传感器系统分析和设计的理论基础;以此理论模型为基础,研究了多参数扰动条件下SAW化学传感器系统设计的关键技术,并设计实现了温度扰动条件下用于沙淋(Sarin)(浓度低于1ppm)气体检测的SAW传感器系统,并对系统在单、多参数扰动下的性能进行了测试和分析。论文的基本内容:1 SAW传感器多参数信息敏感的理论基础SAW的压电振动理论、SAW传感器的扰动理论、SAW器件分析设计理论,分析了SAW信息敏感器件多参数信息敏感的理论基础,为SAW传感器多参数信息敏感系统的数学分析模型的建立奠定了理论基础。2 SAW传感器信息敏感和信号处理模型建立提出了SAW传感器信息—信号映射过程的三个划分:(1)外界扰动量I(信息)到压电基片物理参数ɑ的映射;(2)压电基片物理参数ɑ到SAW信号参数变化的映射;(3) SAW信号参数变化到电信号参数变化的映射。通过对SAW传感器信息—信号映射过程的三个划分,获得了SAW传感器信息敏感失真的主要环节,即外界扰动量I到压电基片物理参数ɑ映射。基于压电基片物理参数对扰动量的“度量”这一概念,提出了描述上述三个映射过程的数学表达,基于这三个数学表达式,建立了SAW传感器的信息敏感模型。在此信息敏感模型的基础上,基于SAW振荡器的电信号频率参数映射能力,建立了SAW传感器的基于信息—电信号频率参数的信号处理模型。该模型反映了SAW传感器失真信息敏感的本质、多参数信息敏感特征以及SAW传感器的抗干扰和误报率性能的理论基础。3 SAW多参数传感器信息敏感和信号处理模型建立基于SAW传感器信息敏感模型和空间阵列信号提供冗余信息的能力,建立了具有多参数信息敏感的SAW传感器多参数信息敏感模型;基于SAW振荡器的电信号频率参数映射能力,把通过SAW敏感器件加载于SAW信号上的任一多参数扰动ΔI j映射为电信号频率参数Δω,建立起了ΔI j到Δω的信号处理模型;基于此并根据SAW传感器多参数信息敏感模型,建立起了时空相关扰动矢量△I到电信号频率矢量△ω映射的SAW多参数传感器信号处理模型—K矩阵,奠定了SAW多参数传感器系统的分析和设计理论基础。4 SAW微量化学气体传感器系统设计及关键技术研究对温度(T)、沙林(G系列)等多扰动的SAW多参数传感器的功能要求、性能指标、环境制约、工艺制约等进行了系统的分析。对影响系统敏感精度、响应速度和信息识别能力等性能指标的关键技术,包括SAW敏感器件阵列设计、SAW振荡器设计、化学吸附膜材料的制备、吸附膜涂覆工艺、SAW传感器的结构设计、SAW传感器的信号处理与检测等进行了深入研究,获得了针对本试验系统性能目标的基本设计要求和最佳设计参数。SAW延迟线器件的最佳结构设计参数和它的最小Q值要求、SAW振荡器的最佳工作频率范围和最小频率稳定度、化学吸附膜材料的最佳吸附方式和其特性的红外表征、化学吸附膜材料的最佳涂覆工艺和旋涂工艺的最佳旋转速度、SAW传感器的最佳信号检测方式以及SAW传感器的结构设计等。在以上分析、研究的基础上,提出了温度(T)、沙林(G)扰动SAW多参数传感器系统的总体设计方案,奠定了SAW微量化学气体传感器系统设计的技术基础。5 SAW微量化学气体传感器系统实现及试验根据上述SAW多参数传感器系统的总体设计方案,实现了SAW微量化学气体传感器系统。并根据SAW微量化学气体传感器系统的性能要求,设计了对部件性能、温度T敏感性能、G化学气体敏感性能以及T、G多参数扰动敏感性能等进行测试的试验系统和方法。基于该试验系统和方法,对传感器系统的部件、温度T敏感、G化学气体敏感以及T、G多参数扰动敏感等性能进行了测试。6 SAW微量化学气体传感器系统性能分析对SAW微量化学气体传感器系统的高稳晶体振荡器、SAW器件温度变化、SAW振荡器的温度变化、化学吸附膜对SAW器件的影响、温度(T)敏感、沙淋(G)化学气体敏感以及T、G多参数扰动敏感等性能的测试数据进行定性和定量地分析。根据测试数据近似计算出了SAW多参数传感器温度(T)、沙林(G)敏感精度和识别误差,结果表明:系统完全达到了要求性能参数,证明了本文提出的SAW多参数传感器系统分析模型的有效性。论文基于信息敏感“度量”概念,针对SAW传感器的高误报率和低抗干扰性能,对SAW传感器课题的研究成果进行了系统的分析和总结,创新性地提出并建立了基于多参数信息敏感的SAW传感器系统的完整的数学分析模型,奠定了SAW多参数传感器系统的设计和分析的理论和技术基础;针对当前对沙淋(G)实时检测的需要,深入研究了影响SAW传感器性能的关键技术,完成了国内首个沙淋(G)和温度(T)多参数扰动下的SAW微量化学气体传感器系统的研制,其中“863”项目“新一代无线通信用SAW器件及材料研究”已于2006年通过国家科委组织的鉴定,课题成果获得2007年度国家发明二等奖;国防基金项目“SAW化学传感器理论与技术研究”项目于2007年6月通过部级鉴定,鉴定结论为“项目研究成果属国内首创,达到国际先进水平”;国防基础预先研究项目“SAW技术研究”已取得关键技术突破,将于近期向用户提供SAW传感器检测器芯片产品,满足用户需求。更多还原

【Abstract】 As one of the key foundations of the modern information technology, the sensor technology has been held great attraction for people. Surface acoustic wave (SAW) sensor using the surface acoustic wave as the information sensing carrier is characterized by high sensing accuracy, short response time, wide range of application and small size. SAW sensors are very promising for meeting the needs of aerospace, food hygiene, environmental monitoring ,medical and chemical industry, process monitoring, military affairs and security services etc.. Especially, as chemical sensors for measuring high fatal chemical warfare agents in real time, SAW sensors exhibit technologies superiority. Now, SAW sensors have become the first choice of the military in every country.Although SAW sensors have such advantages as high sensing accuracy, short response time etc, the worse selection and weak anti-interference are the intrinsic shortcomings of SAW sensors due to the multi-parameter information sensing properties. At the complex conditions, especially at the detection environments of chemical warfare agents in real time, these intrinsic shortcomings have great limitations to the applications of SAW sensors. How to overcome these shortcomings of SAW sensors have become a study topic of general interest. Supporting by the subject of“Theory and Technology Study on SAW Chemical Sensors”, the multi-parameter information sensing theory of SAW sensor and its key technology have been deeply studied. The physical process of the selection and anti-interference of SAW sensor have also been described in this paper.Based on the basic theory and the physical process of SAW sensor information sensing, the partition of the three physical processes of the information-signal mapping and its corresponding mathematical expressions have been proposed. The model of SAW sensor information sensing has been established. Using this information sensing model and on the basis of the SAW signal to electrical signal frequency parameter mapping mechanism of SAW oscillator, the signal processing model of SAW sensor has also been built up. According to these models and the ability of SAW array signals to provide the redundant information, the multi-parameter information sensing model and the multi-parameter signal processing model of SAW sensor—the K matrix, have been set up. Thus, the theoretical foundation of SAW sensor systematic analysis and design based on the multi-parameter information sensing and recognition was put up. The key technology of SAW chemical sensor system design under the multi-parameter disturbance condition has been studied in this paper. A SAW sensor system for measuring Sarin gas with the concentration of less than 1ppm at the temperature disturbance has been designed. The performance of the system under the conditions of single-parameter and multi-parameter disturbance has also been tested and analyzed.The main points of this work were set forth as follows:1. The theoretical foundation of SAW sensor multi-parameter information sensing The theory foundation of SAW sensor, including SAW piezoelectric vibration theory, disturbance theory of SAW sensor and analytic theory of SAW device, was analyzed systematically. The idea that the linear superposition of SAW solution on the piezoelectric substrate is the physical basis of multi-parameter sensing of SAW sensor was proposed in this paper. This laid down the theoretical basis for establishing the mathematic analytic model of SAW sensor multi-parameter information sensing system.2. Establishment of the information sensing and signal processing models of SAW sensorThe full physical process of SAW sensor information sensing was classified innovatively as three basic mapping processes. These are:(1) Mapping from the external disturbance I to the physical parameterαon the piezoelectric substrate(2) Mapping from the physical parameterαon the piezoelectric substrate to change of SAW signal parameter(3) Mapping from SAW signal parameter change to electric signal parameter changeIt was found that the first mapping process of these three mapping processes in SAW sensor information sensing, i.e., mapping from the external disturbance I to the physical parameterαon the piezoelectric substrate, was the key link in causing distortion of SAW sensor information sensing. Based on the idea that the piezoelectric basic physical parameter“measures”the disturbance, the mathematic expressions which describe the three mapping processes is given . According to these mathematic expressions, the mathematic analytic model of SAW sensor multi-parameter distortion information sensing could be established, thus laying down a key technology foundation for establishing the signal model of SAW chemical micro-gas sensor system.3. Establishment of the information sensing and signal processing models of SAW multi-parameter sensorAccording to the mapping from SAW signal based on SAW oscillator to electric signal, any disturbanceΔIj loaded on SAW signal through SAW sensing element was mapped to the expression of frequency parameterΔωof electric signal, and then the signal processing mathematic model fromΔIj toΔωwas established. Based on both this model and the model of multi-parameter information sensing of SAW sensor, the multi-parameter signal processing mathematic model of SAW sensor from the disturbance vectorΔI correlated with the time-space to the frequency vectorΔωof the electric signal was established, thus converting effectively the multi-parameter sensing of SAW sensor into the orthogonalization processing of the electric signal and realizing the integrated signal processing of SAW sensor multi-parameter information sensing identification technology. As a result, not only the current SAW sensor multi-parameter information sensing identification technologies could be analyzed and evaluated, but also can point out the way for developing new SAW sensor multi-parameter information sensing identification technology.4. Study on the key technology of SAW chemical micro-gas sensor system and the system designSAW multi-parameter sensor system for measuring the micro-gas of sarin (G) at temperature disturbance was analyzed. The key techniques which may influence the accuracy of system sensing, response speed and information identification ability, including design of SAW sensing device array, design of SAW oscillator, preparation of chemical absorption film material, coating technique of absorption film, the structural design of SAW sensor, signal processing and measurement of SAW sensor etc., were investigated in depth. The basic design requirements and optimal design parameters for reaching the performance goal of this experimental system were obtained, such as the optimal structural design parameters of Saw delay line and the minimum Q value requirement, the optimal operating frequency range of SAW oscillator and the minimum frequency stability, the optimal absorption method of chemical absorption film material and infrared characterization of its property, the optimal coating technique of chemical absorption film material and the minimum rotation speed of spinning coating technique, the optimal signal measurement method of SAW sensor and the structural design of SAW sensor. All of these works have laid down a foundation for designing SAW chemical micro-gas sensor system.5. Realization of SAW chemical micro-gas sensor system design and sensor system experimentSAW chemical micro-gas sensor system was designed based on the information sensing model and signal processing model of SAW multi-parameter sensor. The component performances of SAW chemical micro-gas sensor system, sensing performance of temperature T and chemical gas G as well as the disturbance sensing performance of T and G multi-parameters were tested.6. The performance analysis of SAW chemical micro-gas sensor systemThe test data of the high stable crystal oscillator, the temperature variations of SAW device and SAW oscillator, effect of the chemical absorbing film on SAW device, the temperature (T) sensing and the chemical gas of Sarin (G) sensing, as well as the multi-parameters T and G disturbance sensing have been analyzed quantitatively and qualitatively. Based on these test data, the sensing accuracy and the recognition error of the temperature (T) and Sarin (G) of SAW multi-parameter sensor have been calculated approximately. The results have showed that the SAW sensor system meets the design specifications perfectly. The correctness of the analytical model of SAW multi-parameter sensor system has been demonstrated.From the viewpoint of the information sensing system, SAW sensor system has been studied in this paper. Aiming at the high rate of misrecognition and weak anti-interference, a whole mathematic analytical model of SAW sensor system based on the multi-parameter sensing has been proposed and established innovatively. The theoretic and technology foundations of the design and analysis of SAW multi-parameter sensor system have been built up. To meet the urgent requirements for measuring Sarin (G) gas in real time, SAW chemical micro-gas sensor system at the multi-parameter disturbance of Sarin (G) and temperature (T) has been developed firstly in domestic. This work will propel the development of SAW sensor technology in China forward.更多还原