CMOS capacitive pressure sensor design and integration with RFID tag for biomedical applications

RFID is evolving as a major technology enabler for identifying and tracking goods. RFID applications in biomedical area not only need to detect but also require monitoring and transmitting vital signals like heartbeat. A cantilever based capacitive pressure sensor for detecting the heartbeat signal is discussed in this paper. A simple sensor with only few process steps compatible to standard CMOS flow is proposed. The basic structure of the sensor along with fabrication steps has been studied. The feasibility of fabrication and immunity from unwanted pressure/noise variations are mainly considered during the optimization of the sensor. The sensor output signal is further processed using a current to voltage differential amplifier. The sensor is integrated with the other blocks of RFID tag and the entire circuit is verified by simulation. This work would be very relevant for the sensing and remote monitoring of biomedical signals.