Piezoelectric–Piezoresistive Coupling MEMS Sensors for Measurement of Electric Fields of Broad Bandwidth and Large Dynamic Range

Abstract

Electric-field microelectro-mechanical systems sensors with broad bandwidth and large dynamic range are an enabling technology for real-time monitoring of fast transient overvoltage in the power grid. They significantly alter lightning damage and operation faults and therefore help establish a more secure grid. In this paper, we propose a new method and architecture for electric-field sensing, which overcomes the incompatibilities between electric-field measurements of broad spectrum and large dynamic range. Scientifically, this compound structure with coupled piezoelectric effect and piezoresistive effect transduces electric field changes into resistance alterations via internal pressure. This structure has an hour-glass-shaped cavity, which contains a piezoelectric crystal and leaves the piezoresistive membrane vibrating freely. The newly proposed sensors have a broadened frequency bandwidth of up to 100 kHz and a 15-fold improved sensing magnitude. In addition, this sensor decreases the cost by two orders and reduces energy consumption to 0.018%, which makes them readily implantable into electrical appliances in the power grid.