MOde-localized mass Sensors with Thermal Actuation and Piezoresistive DEtection (MOSTAPDE)

Weakly coupled resonant sensors have recently generated considerable interest in the sensor community as they were proven to have orders of magnitude higher sensitivity to a change in mass than other sensing principles. They are based on an effect called mode-localization: when two (or more) identical micro-resonators are coupled by a spring and the symmetry of the system is broken by a small change in mass of one resonator, the vibration pattern changes, which can be detected electrically. To achieve the high sensitivity, the resonators require low damping but air or liquid are not a suitable medium. However, many real work applications such as air quality sensing or bio-analyte concentration measurements take place in such mediums (air or water) - the change in mass is caused by docking of the analyte on one resonator. We will investigate novel solutions to this fundamental problem by combining thermal excitation and piezo-resistive detection to coupled resonators for the first time, which promises to result in sufficiently low damping. We will also apply novel feedback mechanisms so that it is ensured that the resonators always are operating at their natural resonance frequency (which shifts with a change in mass). Furthermore, we will explore fundamental aspects of coupled resonator sensors that have not been sufficiently investigated: bandwidth, linearity and resolution; especially about the latter there is disagreement as it requires a rather difficult noise analysis.