Study of the damping processes in thickness shear mode resonator chemical sensors

This work illustrates an alternative method of extracting signals from thickness shear mode resonator sensors. The basic idea consists of modulating the voltage supply of an oscillator circuit driven by a quartz element. The sensor signal can then be obtained measuring the time decay of the output signal in the off state, where some energy, stored in the on state, is released in the form of a damping oscillation. It has been experimentally proven that the time decay in the off state can be reproducibly related to the quartz loading by a remarkable sensitivity function. This paper shows most of the results obtained so far by this technique and discusses the general performance, advantages and disadvantages as well as comparison with the standard frequency measurement technique.