A Single-Chip 3-D Electric Field Microsensor With Piezoelectric Excitation

This article proposes a single-chip 3-D electric field microsensor (3-D EFM) with piezoelectric excitation to reduce the excitation voltage and crosstalk noise and improve the performance of the microsensor. The microsensor is composed of one group of shielding electrodes and four sets of symmetrically distributed sensing electrodes. The shielding electrodes vibrate vertically with piezoelectric excitation, and currents can be induced in the four sets of sensing electrodes under the external electric field. The signals related to the electric field components along the ${x}$ , ${y}$ , and ${z}$ three coordinate axes can be calculated through the periodic induced currents. A theoretical model for the microsensor is set up. The finite-element simulation is conducted to verify the working principle and optimize the key structural parameters. The fabrication process is designed and successfully realized. Experiments are conducted on the single-chip 3-D EFM, and the results show that under 2-V ac driving voltage; the output sensitivity is 0.2315 mV/kV/m for the ${x}$ -axis, 0.3727 mV/kV/m for the ${y}$ -axis, and 2.187 mV/kV/m for the ${z}$ -axis. The linearity errors of the three coordinate axes are within 2.77% in the range of 0–50 kV/m. The maximum measurement error of the 3-D EFM is less than 8%.