RFID MEMS Sensor Concept Based on Intermodulation Distortion

This paper presents a passive wireless microelectromechanical systems (MEMS) sensor consisting of an antenna directly matched to a MEMS resonator. When the sensor is actuated at two signals at different frequencies it replies at an intermodulation frequency. An analytical equation for the mixing efficiency of a MEMS sensor is derived and verified by harmonic balance simulations. The concept is demonstrated experimentally and shown to be feasible for implementing sensors or tags readable across large distances.