A Wireless Sensor Interrogator Design for Passive Resonant Frequency Sensors Using Frequency Modulation Spectroscopy

This paper presents a wireless sensor interrogator design based on frequency modulation spectroscopy (FMS). The wireless sensor interrogator is capable of wireless detection and tracking of the resonant frequency of a passive inductor-capacitor circuit. The wireless interrogator has been successfully simulated and implemented in hardware. Compared to other wireless sensor interrogation techniques, FMS enables not only detection, but also tracking of the sensor´s changing resonant frequency over time. The theory of FMS is discussed briefly, followed by the results from both the simulation and the hardware implementation. The hardware implementation of the wireless sensor interrogator is able to lock onto and track the resonant frequency of a passive inductor-capacitor resonant circuit.