High-performance micro electric field sensors enabled by nonlinear dynamics regulation

As the core component in electric field detection systems, electric field sensors have been widely applied in key fields such as high-voltage power transmission, atmospheric monitoring, electrostatic protection, and aerospace. In practical applications, the operational characteristics of resonator-based sensors are often established under the assumption of linear system responses. However, with increasing demands for high sensitivity and high resolution in electric field measurements, enhancing the performance of electric field sensors has become a research hotspot in recent years. The applicability of traditional electric field sensors based on linear operating mechanisms is gradually being challenged. In this work, we propose a novel approach to improve the performance of resonant MEMS electric field sensors by harnessing nonlinear effects. The study systematically explores how nonlinear dynamics can be controlled and exploited to boost sensing capability under large-signal excitation conditions. A detailed analysis is first conducted on the sensor’s structural design and electric field sensing principle. The sensor’s core components include a drive electrode, sensing electrode, movable shielding electrode, folded beams, and fixed anchors. Based on electrostatic induction and Gauss’s law, the sensitive structure generates an induced current proportional to the external electric field intensity, which enables field strength measurement through current detection. The nonlinear behavior of the resonator and its control scheme are then introduced, with particular attention to the physical origins and manifestations of nonlinearity, such as geometric and material nonlinearities, as well as mode coupling effects. Two analytical models are developed: a linear vibration model for small-signal excitation, and a nonlinear model incorporating a cubic Duffing term for large excitation conditions. Frequency response characteristics and sensitivity expressions are derived for both regimes, providing theoretical support for later experimental validation and offering insights into how nonlinearity influences sensor performance. To further investigate the nonlinear characteristics, a 3D model of the sensor is constructed using COMSOL Multiphysics 6.0 for structural simulation. A complete experimental platform is then developed, including a precision excitation circuit, differential current readout circuitry, and a data acquisition and analysis system. This setup allows precise control of excitation amplitude and frequency, enabling systematic investigation of the resonator’s dynamic behavior under varying conditions. The experiments focus on the resonator's nonlinear vibrations in its second-order mode. By adjusting parameters such as excitation amplitude and bias voltage, the study explores methods for effectively controlling the sensor’s operation within the nonlinear regime. The results reveal the impact of nonlinear vibration on sensor performance and demonstrate how careful tuning of nonlinear effects can significantly enhance key metrics. In particular, under optimized nonlinear operating conditions, the sensor achieves a maximum sensitivity of 4.77 mV/(kV/m) and an improved resolution of 0.22 V/m·√Hz. These findings confirm the feasibility and effectiveness of leveraging nonlinear mechanisms to enhance MEMS electric field sensor performance. This work not only offers a new approach for achieving high-precision electric field detection but also showcases the considerable potential of nonlinear resonator technology in demanding application scenarios. With increasing performance requirements in fields such as smart grids, environmental monitoring, and aerospace systems, the integration of controlled nonlinearity is expected to become a powerful strategy for next-generation electric field sensor design.