摘要
薄膜体声波谐振器(FBAR)不仅能作为手机射频前端的滤波器,还具有充当传感器表头的潜力。为实现对体声波(BAW)传感器输出射频信号的检测,设计一种基于Pierce振荡器的BAW传感器读出电路。读出电路采用双路差分方式,将体声波谐振器构成两路振荡器,一路作为参考电路用于检测外界环境等因素的干扰,另一路作为传感电路用于检测待测物理量。两路振荡器信号通过混频滤波得到由待测物理量引起的谐振频率偏移。然后通过放大与整形将模拟信号转换为数字信号,最后送入FPGA进行频率检测。以一个2 GHz的体声波质量传感器为例,给出电路各模块的设计方法,经各模块仿真以及信号转换电路的实验验证,电路可检测的最大谐振频率偏移量为99 MHz。
Film bulk acoustic resonator（FBAR） can not only be used as a filter for the RF front end of a mobile phone, but also has the potential as a sensor head. In order to realize the detection of the RF signal output from the BAW sensor, a BAW sensor readout circuit based on Pierce oscillator is designed. This paper uses the differential measurement method, which using two BAWRs to constitute two oscillators, one as a reference circuit to detect interfere factors and the other as a measurement circuit to detect physical quantity to be measured. The resonant frequency offset caused by the physical quantity to be measured is obtained by mixing and filtering the two oscillator signals. Then, the analog signal is converted to digital signal by amplifying and shaping. Finally the signal output from shaping circuit is sent to FPGA for fre-quency detection. Taking 2 GHz bulk acoustic wave sensor as an example, with the design method of each circuit module given in this paper. Through the simulation of each circuit mod-ule and the experimental verification of the signal conversion circuit, the maximum detectable resonant frequency offset is 99 MHz of the circuit.
出处
《中国测试》
北大核心
2017年第9期81-87,共7页
China Measurement & Test
基金
国家自然科学基金(61574131)
中国工程物理研究院超精密加工技术重点实验室基金(2014ZA001)
核探测与核电子学国家重点实验室开放课题基金(2016KF02)
西南科技大学研究生创新基金(16YCX103)
