LC wireless passive flexible pressure sensor formulated with a microstructured ionogel

With the rapid development of the Internet of Things technology, wireless sensor networks have demonstrated prominent application value in industrial monitoring, environmental monitoring, and intelligent transportation. Traditional pressure sensors suffer from drawbacks such as inconvenient maintenance and limited service life, whereas the inductance–capacitance (LC) resonant wireless sensing architecture can effectively address these problems. Relying on a high-frequency structure simulation, this study optimized the structural parameters of the devices, integrated microstructured-ionogel dielectric with LC oscillator resonant units, and fabricated passive wireless pressure sensors. The ionic gel deforms under an external force, and the pressure variation is converted into a resonant frequency drift of the circuit via the double-capacitance effect generated by electric double-layer polarization, realizing non-contact wireless signal acquisition based on backscatter signals. The as-fabricated wireless pressure sensors achieved sensitivities of 3194 and 239.8 kHz·kPa−1 in the low-pressure (0–20 kPa) and high-pressure (20–166 kPa) ranges, respectively. Quantitative experiments for hysteresis error, long-cycle durability, and environmental adaptability tests under variable temperature and humidity conditions verified the operational reliability of the device. Owing to its outstanding flexibility and signal repeatability, this sensor can find application in wearable physiological signal monitoring, facial microexpression recognition, and clinical medical detection.