Investigation into Mass Loading Sensitivity of Sezawa Wave Mode-Based Surface Acoustic Wave Sensors

Sensors

Ajay Achath Mohanan¹  Md Shabiul Islam³  Sawal Hamid Md Ali²  R. Parthiban¹ 

[1]Electrical and Computer Systems Engineering, School of Engineering, Monash University Sunway Campus, Jalan Lagoon Selatan, Bandar Sunway 46150, Malaysia

[2] E-Mails:

[3]Department of Electrical Engineering, Electronics & Systems, Faculty of Engineering & Built Environment, Universiti Kebangsaan Malaysia (UKM), Bangi 43600, Malaysia

[4] E-Mail:

[5]Institute of Microengineering and Nanoelectronics (IMEN), Universiti Kebangsaan Malaysia (UKM), Bangi 43600, Malaysia

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关键词: surface acoustic wave devices;    Sezawa wave mode;    mass loading effect;    sensors;    FEM simulation;   

DOI  :  10.3390/s130202164

来源: mdpi

【 摘 要 】

In this work mass loading sensitivity of a Sezawa wave mode based surface acoustic wave (SAW) device is investigated through finite element method (FEM) simulation and the prospects of these devices to function as highly sensitive SAW sensors is reported. A ZnO/Si layered SAW resonator is considered for the simulation study. Initially the occurrence of Sezawa wave mode and displacement amplitude of the Rayleigh and Sezawa wave mode is studied for lower ZnO film thickness. Further, a thin film made of an arbitrary material is coated over the ZnO surface and the resonance frequency shift caused by mass loading of the film is estimated. It was observed that Sezawa wave mode shows significant sensitivity to change in mass loading and has higher sensitivity (eight times higher) than Rayleigh wave mode for the same device configuration. Further, the mass loading sensitivity was observed to be greater for a low ZnO film thickness to wavelength ratio. Accordingly, highly sensitive SAW sensors can be developed by coating a sensing medium over a layered SAW device and operating at Sezawa mode resonance frequency. The sensitivity can be increased by tuning the ZnO film thickness to wavelength ratio.

【 授权许可】

CC BY   
© 2013 by the authors; licensee MDPI, Basel, Switzerland.