体声波传感器检测电路设计

发布时间：2018-02-22 23:31

本文关键词： 体声波谐振器 BAW传感器 BAW振荡器频率稳定度检测电路　出处：《西南科技大学》2017年硕士论文　论文类型：学位论文

【摘要】：由于体声波(Bulk Acoustic Wave,BAW)传感器具有体积小、灵敏度高、工作频率高、功率损耗低和互补金属氧化物半导体(Complementary Metal Oxide Semiconductor,CMOS)兼容的特点,因此BAW传感器具有广泛的应用前景。BAW传感器通过检测体声波谐振器(Bulk acoustic Wave Resonator,BAWR)的谐振频率变化得到待测物理量。本文旨在设计BAW传感器的检测电路,检测BAWR在受到待测物理量作用时产生的谐振频率偏移,最终实现待测物理量的检测。由于BAWR易受到环境等因素的干扰,导致检测结果不准确,本文采用双路差分的测量方法,将BAWR构成两路振荡器,一路用于参考另一路用于测量。两路振荡器通过混频、滤波得到由待测物理量引起的谐振频率偏移信号,之后将该信号通过放大、整形电路转换为方波信号,最后采用频率检测电路得到方波信号的频率。建立了基于Pierce架构的BAW振荡器,将BAWR谐振频率的变化反映到振荡频率的变化上。提出了BAWR的质量负载等效电感的量化方法,用质量负载等效电感来模拟待测的质量,解决了无法对BAW质量传感器进行系统级行为仿真的难点。研究了影响BAW振荡器频率稳定度的因素,并对BAW振荡器的频率稳定度和功耗进行了优化,改善了BAW振荡器的综合性能。对信号转换电路进行了设计,包括混频器、放大器和整形电路。采用微带分支定向耦合器、混频二极管和低通滤波器构成混频器,并对混频器进行了场-路联合仿真,得到了两路振荡信号的频率差。对信号转换电路进行了制作与测试,测试结果与仿真结果对比基本吻合,验证了电路的可行性。针对信号转换电路输出的方波信号,采用现场可编程门阵列(Field Programmable Gate Array,FPGA)设计了频率检测电路。以自顶向下的方式,采用精度较高的全同步测频法,根据具体工作原理设计了频率检测电路的各个子模块,通过仿真验证了每个模块的功能。最后通过元件例化语句将子模块连接起来构成顶层模块,通过顶层模块仿真,得到了在不同的被测信号频率的输入条件下的仿真结果,验证了电路功能的正确性。
[Abstract]:Bulk Acoustic wave (bulk Acoustic wave) sensors are small in size, high in sensitivity, high in operating frequency, low in power loss and compatible with complementary Metal Oxide Semiconductors (CMOS). Therefore, the BAW sensor has a wide application prospect. The BAW sensor obtains the physical quantity to be measured by detecting the change of the resonant frequency of bulk acoustic Wave Resonator. This paper aims to design the detection circuit of BAW sensor. The resonance frequency offset of BAWR is detected when it is acted on by the physical quantity to be tested, and the detection of the physical quantity to be tested is finally realized. Because the BAWR is easily disturbed by the environment and other factors, the detection result is not accurate. In this paper, the method of double channel differential measurement is used. The BAWR is used to form a two-channel oscillator, one of which is used for reference to the other one for measurement. The oscillator filters the resonant frequency offset signal caused by the physical quantity to be measured by mixing the frequency of the oscillator, and then amplifies the signal. The shaping circuit is converted into square wave signal. Finally, the frequency of square wave signal is obtained by frequency detection circuit. A BAW oscillator based on Pierce architecture is established. The variation of BAWR resonance frequency is reflected in the change of oscillation frequency. A quantization method of mass load equivalent inductance of BAWR is proposed. The mass is simulated by mass load equivalent inductance. The difficulty of system-level behavior simulation of BAW mass sensor is solved. The factors influencing the frequency stability of BAW oscillator are studied, and the frequency stability and power consumption of BAW oscillator are optimized. The integrated performance of BAW oscillator is improved. The signal conversion circuit is designed, including mixer, amplifier and shaping circuit. The mixer is composed of microstrip branching directional coupler, mixing diode and low pass filter. The frequency difference of the two oscillating signals is obtained by the field-circuit combined simulation. The signal conversion circuit is fabricated and tested, and the test results are in good agreement with the simulation results. The feasibility of the circuit is verified. For the square wave signal output from the signal conversion circuit, a frequency detection circuit is designed using Field Programmable Gate Array (Field Programmable Gate ArrayFPGA). In a top-down manner, a fully synchronous frequency measurement method with high precision is adopted. Each sub-module of frequency detection circuit is designed according to the specific working principle, and the function of each module is verified by simulation. Finally, the sub-module is connected to form the top-level module through the component example statement, and the top-level module is simulated by the top-level module. The simulation results are obtained under different input conditions of the measured signal frequency, and the correctness of the circuit function is verified.
【学位授予单位】：西南科技大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TP212

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