Wearable Temperature Sensing Bandages Based on Fano Resonance

LC wireless sensors are excelling in wearable devices with the advantages of wireless interrogations and compatibility with multiple processes. However, the high intrinsic loss of LC resonance hinders the improvement of sensitivity. To overcome the limitation, we propose a wearable temperature sensing bandages based on LC Fano resonance. A wirelessly powered negative impedance is integrated into the LC temperature sensor to generate a discrete spectrum, while the external readout coil, driven by signal analyzer, provides a continuum spectrum. The asymmetric Fano resonance is formed via mutual coupling between the readout circuit and the LC sensor, which results in high resolution. We fabricate the sensing system on PI embedded in bandages with polyethylene-glycol-based temperature sensitive capacitor. To imitate human applications, we conduct the experiments by ranging the temperature from 36°C to 42°C. The results show that Fano-resonant temperature sensor achieves a resolution of 0.04°C.