Capacitive pressure sensor based on tilted micropillars

Abstract As a core component in precision pressure detection, improving the sensitivity of capacitive pressure sensors is critical for advancing high-precision sensing technology. To overcome the limited sensitivity enhancement in conventional sensors that rely only on compressing the dielectric layer to reduce electrode spacing, this work proposes a novel sensor structure consisting of a tilted micropillar dielectric layer and interdigital electrodes. The tilted micropillars bend under applied pressure, which simultaneously reduces electrode spacing and increases the effective overlapping area, thus amplifying the pressure-induced capacitance change.3D printing is used to fabricate molds for dielectric layers with various tilt angles. After sensor fabrication, performance tests are conducted using dedicated experimental setups. The effects of excitation frequency, micropillar tilt angle, planar electrodes and interdigital electrodes on sensor performance are analyzed, along with stability and application tests. Experiments confirm that 1 MHz is the optimal test frequency, and the structure with a 75° tilted angle combined with interdigital electrodes delivers the best overall performance. The optimized sensor achieves an outstanding sensitivity of 1.15 kPa⁻¹ in the low-pressure range (0-1 kPa), together with fast response–recovery characteristics, excellent cycling stability, and precise vibration signal recognition. Moreover, the sensor features simple fabrication and low cost, making it suitable for mechanical equipment vibration monitoring with reliable weak signal capture. This study provides a new strategy for structural optimization of capacitive pressure sensors, and the developed sensor exhibits promising prospects in industrial equipment health monitoring.