A lateral field excited acoustic wave sensor platform

Acoustic wave sensing platforms may employ bulk acoustic waves (BAWs) and a variety of surface guided waves. The most common platform however is the quartz crystal microbalance (QCM) in which a purely transverse shear mode (TSM) is excited by electrodes deposited on both faces of an ATcut quartz wafer. In this sensor mechanical property changes in a target analyte are sensed. However, electrical property changes cannot be detected due to the conducting electrodes on the sensing surface. Further, in a QCM array the electrodes and mterconnects on t e sensmg sur ace toter ere wit t e target analyte. A lateral field excited (LFE) BAW sensor platform as oeen introduced to overcome defictenctes m the QCM. In this sensor t e e ectro es are on t e ottom surface of the waler leaving the top sensing surface bare. This allows one to monitor mechanical and electrical property changes in the target analyte. The objective of this paper is to review the LFE sensing platform theoretically and experimentally. Application of the LFE sensor to detect mechanical and electrical changes in fluids is presented followed by examples relating to the detection of chemical and biological analytes.