The Limit of LC Passive Wireless Sensing: Multiple Coupled Modes

Inductor–capacitor (LC) sensors feature passive wireless detections under harsh and sealed environments. With the booming demands of multiple parameters detection in an integrated chip, the research of multicoupled LC sensors is urgently needed. In this letter, we explored the multiple coupled LC sensors system to reveal the amplitude limit of detection, whose minimum value determines the frequency discrimination. We demonstrated that the amplitude of the sublow-resonant frequency is the minimum due to the inhomogeneous energy distribution, which limits the signal-to-noise ratio of the overall system. The research results and conclusions can guide the design and signal analysis of multiparameter LC sensors and can be extended to the signal analysis of other multiple wireless electromagnetic coupling sensor systems.