Hybrid telemetric MEMS for high temperature measurements into harsh industrial environments

A temperature sensor that could be interrogated contactless represents an attractive solution for measurements into harsh environments such as in presence of high temperatures that do not permit the correct working of electronics. This paper discusses a telemetric system consisting of two coupled planar inductors, which constitute a coupled transformer with the primary one connected to the measurement electronics and the secondary one to a capacitive MEMS sensor that is designed for high-temperature environments. The proposed hybrid sensor is composed by the capacitive MEMS bonded to the planar inductor. The hybrid sensor behaves as an LC resonant circuit in which the MEMS represents the capacitance and the planar inductor is the inductance. The whole system has been tested in the laboratory and several results are reported. The proposed telemetric temperature system can be a solution for efficiency monitoring and predictive maintenance for harsh and complex environments.