Corrugated micro-diaphragm analysis for low-powered and wireless Bio-MEMS

Surface Acoustic Wave (SAW) device based wirelessly operated, batteryless and low-powered microdiaphragm structures have been investigated and presented in this paper. These diaphragms are intended to establish the actuation mechanism for micropumps and similar microfluidic devices. The actuation method of the diaphragm relies on the electrostatic coupling between the diaphragm and the output Inter Digital Transducer (IDT) of the SAW device. In this paper, the theory governing the SAW device based novel actuation mechanism, is elaborated using the parallel plate approximation in electrostatic actuation. To validate the theoretical model, a Finite Element Model (FEM) is developed using ANSYS simulation tools and presented. Different design methods are considered to enhance the deflection of the diaphragm for a low input voltage. As such, inclusion of corrugations around a flat square-shaped diaphragm and selection of different bio-compatible materials for various sections of the diaphragm are analysed at the simulation level. Deflection of the diaphragm is obtained as a function of the electric potential at the output IDT of the SAW device, and compared with results obtained from published research.