Motion-Modulated Intermodulation Sensors

This paper presents an intermodulation sensor that can backscatter the third and fifth order intermodulation products and modulate each component by the rotational speed of the transponder. This sensor can be used to achieve accurate measurement and remote monitoring of the rotational speed of an object, even if other objects are rotating at different speeds in the vicinity of the sensor. This sensor can also be identified using the variation of the modulated power backscattered as a function of the frequency. This identification scheme is independent of the rotational speed of the sensor and provides a robust way to identify the sensor in a real environment compared to conventional motion-modulated sensors.