Electromechanically coupled feedback loops for microsystems. Application to volatile organic compounds (VOC) sensors

This paper reports a novel design of an oscillator based on a silicon resonator with an electromechanical coupling using piezoelectric excitation. Lumped parameters modeling has been developed and employed to design the circuit and a version of the oscillator has been built and used in a VOC sensor. Extensive measurements with toluene have been carried out showing a sensitivity of 10 Hz/100 ppm over an oscillation frequency of 186.2 kHz and down to 25 ppm while keeping low both power consumption and cost.