Active control scheme for improving mass resolution of film bulk acoustic resonators  

作　　者：贺学锋 刘兴 印显方 温志渝 陈可万 

机构地区：[1]Key Laboratory of Optoelectronic Technology and Systems of Ministry of Education of China,Chongqing University [2]Microsystem Research Center,Chongqing University

出　　处：《Applied Mathematics and Mechanics(English Edition)》2011年第6期749-756,共8页应用数学和力学（英文版）

基　　金：Project supported by the National Natural Science Foundation of China (No. 61076106);the National High Technology Research and Development Program of China (863 Program) (No. 2008AA04Z310);the Cultivation Fund of the Key Scientific and Technical Innovation Project of Ministry of Education of China (No. 708072)

摘　　要：High mass resolution of sensors based on film bulk acoustic resonators （FBARs） is required for the detection of small molecules with the low concentration. An active control scheme is presented to improve the mass resolution of the FBAR sen- sors by adding a feedback voltage onto the driving voltage between two electrodes of the FBAR sensors, The feedback voltage is obtained by giving a constant gain and a constant phase shift to the current on the electrodes of the FBAR sensors. The acoustic energy produced by the feedback voltage partly compensates the acoustic energy loss due to the material damping and the acoustic scattering, and thus improves the quality factor and the mass resolution of the FBAR sensors. An explicit expression relating to the impedance and the frequency for an FBAR sensor with the active control is derived based on the continuum theory by neglecting the influence of the electrodes. Numerical simulations show that the impedance of the FBAR sensor strongly depends on the gain and the phase shift of the feedback voltage, and the mass resolution of the FBAR sensor can greatly be improved when the appropriate gain and the phase shift of the feedback voltage are used. The active control scheme also provides an effective solution to improve the resolution of the quartz crystal microbalance （QCM）.High mass resolution of sensors based on film bulk acoustic resonators （FBARs） is required for the detection of small molecules with the low concentration. An active control scheme is presented to improve the mass resolution of the FBAR sen- sors by adding a feedback voltage onto the driving voltage between two electrodes of the FBAR sensors, The feedback voltage is obtained by giving a constant gain and a constant phase shift to the current on the electrodes of the FBAR sensors. The acoustic energy produced by the feedback voltage partly compensates the acoustic energy loss due to the material damping and the acoustic scattering, and thus improves the quality factor and the mass resolution of the FBAR sensors. An explicit expression relating to the impedance and the frequency for an FBAR sensor with the active control is derived based on the continuum theory by neglecting the influence of the electrodes. Numerical simulations show that the impedance of the FBAR sensor strongly depends on the gain and the phase shift of the feedback voltage, and the mass resolution of the FBAR sensor can greatly be improved when the appropriate gain and the phase shift of the feedback voltage are used. The active control scheme also provides an effective solution to improve the resolution of the quartz crystal microbalance （QCM）.

关 键 词：film bulk acoustic resonator sensor active control IMPEDANCE RESOLUTION 

分 类 号：TP212[自动化与计算机技术—检测技术与自动化装置]