Frequency coupling and energy trapping in mesa-shaped multichannel quartz crystal microbalances

Abstract

Mesa-shaped quartz structures have received much attention recently due their ability to trap vibration energy and also decouple the thickness shear (TS) mode from other spurious modes. By using Mindlin's first-order theory, the frequency coupling and energy-trapping problem is studied for AT-cut mesa-shaped multichannel quartz crystal microbalances (MQCM). The coupling between the TS and flexural vibrations is considered. Results show that the mesa structure is able to trap more TS vibration energy within the electrode area compared with a conventional electrode plate and hence the frequency coupling between channels in MQCM can be reduced greatly by using mesa structures. Thus, a multichannel sensor system may be implemented more efficiently on a single chip. © 2003 Elsevier B.V. All rights reserved.