Wireless Measurement System for Capacitive pressure Sensors Using Strain Compensated SiGeB

A prototype of miniaturized, low power, bidirectional wireless communication system was designed for in vivo pressure monitoring. The capacitive pressure sensors have been developed particularly for the medical field, where packaging size and minimization of the power requirements of the sensors are the major drivers. The pressure sensors have been fabricated using a 2.4 mum thick strain compensated heavily boron doped SiGeB. In order to integrate the sensors with the wireless module, the sensor dice was wire bonded onto TO package using chip on board (COB) technology. The telemetric link and its capabilities to send information have been examined on a test bench. A full pressure range from 0 to 10 kPa was generated using either air or water pressure pumped through connected tubes to simulate the environment similar to the one inside the gastro intestinal (GI) tract.