A MEMS Vertical Fringe Comb Capacitive Pressure Sensor for Biomedical Application
K. Shah, H. Thumu, V. Vibhute, J. Singh and H.P. Le
Center of Telecommunication and Microelectronics, AU
MEMS, capacitive pressure sensors, biomedical, modeling
This paper presents the design and implementation of a Micro Electromechanical Systems (MEMS) vertical fringe comb capacitive pressure sensor using Coventorware and Cadence SpectraRF Electronic Design Automation (EDA) tools. The pressure sensor is designed to operate in a pressure range of 0 to 300mmHg and is targeted for biomedical application of blood pressure or heart beat rate sensing. MEMS sensors are widely used in biomedical applications due to its advantages of miniaturisation, low power consumption, ease of measurement and telemetry. However, present pressure sensors typically utilises parallel plate capacitors, which are large in size and are required to be operated in touch mode for good linearity. In this design vertical fringe capacitor structure is employed to reduce the system area, increase the system linearity and have larger full scale change in capacitance compared to its parallel plate counterparts. Results show that for the pressure range of 0 to 300mmHg the device capacitance range of 1.31pF to 1.98pF is achieved which results in a frequency sweep of 2.54GHz to 1.95GHz. A full-scale change in capacitance of 680fF was obtained with device sensitivity of 0.25fF/mmHg with good linearity over the whole range.
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Nanotech 2005 Conference Program Abstract