"Bent beam" MEMS Temperature Sensors for Contactless Measurements in Harsh Environments

A novel MEMS temperature sensor based on a cascade three-stage bent beam structure is described in this work. Three cascaded systems compose the structure in order to enhance sensor sensitivity. The structure is mechanically deforms as a response to the change in the ambient temperature and then a displacement is obtained that is furthermore amplified by the cascaded architecture. The final conversion is toward an electrical signal that is obtained by using an interdigited capacitor embedded into the moving tip of the MEMS sensor. The device has been conceived to operate into high temperature environments and to be remotely read-out. An external coil inductor has been figured out in this first prototype to realize a resonant LC circuit, where the capacitor changes with the temperature to be measured, and which can remotely be tuned with a magnetically coupled circuit reader. Analytical and numerical models have been developed and preliminary experimental results are reported here to show a good accordance with expectations. Vernier scales have been suitably positioned to quantify the deformations during the first characterization phase such to perform a comparison with the expected behavior.