High-sensitivity flexible wireless passive LC pressure sensor enabled by a magnetic field-induced ciliary microstructure

Abstract Flexible wireless passive inductance–capacitance (LC) pressure sensors exhibit considerable potential in diverse pressure monitoring applications. Nevertheless, their performance has been persistently constrained by the intrinsic trade-off between sensitivity and detection range. In this study, a flexible LC pressure sensor with high sensitivity is presented, employing a dielectric layer engineered with a magnetic field-induced ciliary microstructure this enhanced performance is achieved through the synergistic optimization of microstructural design and the precise modulation of dielectric material properties. The designed dielectric layer introduces a directional magnetic field during the curing process of the PDMS matrix doped with hydroxyl iron powder, simultaneously achieving the chain-like ordered arrangement of hydroxyl iron particles and the controllable construction of polymer cilia microstructures. This magnetically engineered ciliary microstructure breaks the inherent sensitivity-range trade-off through a gradient compression deformation mechanism, enabling both ultrahigh low-pressure sensitivity and a broad linear detection range. The resulting LC sensor exhibits excellent comprehensive performance with a sensitivity of 2824 kHz kPa −1 in the 0–20 kPa range and a stable response of 76.6 kHz kPa −1 in the 20–200 kPa range, successfully balancing high sensitivity and wide range. It also features rapid dynamic response (180 ms 200 ms) −1 , an ultra-low detection limit (8 Pa), good cycle stability, and excellent temperature and humidity adaptability. Wireless testing shows that its quality factor Q value can reach 55, demonstrating efficient signal transmission and resonant characteristics. The sensor demonstrates high precision and reliable signal response. The study provides a new approach to solving the inherent trade-off between sensitivity and range of flexible wireless pressure sensors through the collaborative optimization of microstructure design and dielectric materials, laying a technical foundation for their application in wearable health monitoring and interactive devices, and showing promising application prospects.