Design and analysis of a planar quasistatic electric field sensor based on nonlinearity of ferroelectric materials

In this paper, a planar quasistatic electric field sensor is proposed. This type of sensor is based on the dielectric nonlinearity behavior of a ferroelectric material and a pair of coplanar interdigital electrodes. The interdigital electrodes functioning as driving electrodes are machined on the surface of the ferroelectric material to form a planar inter-digital capacitor. A sensing electrode placed between adjacent driving electrodes is connected to a copper plate, which is exposed in external electric field. The copper plate operates as a charge collector and immediately transfers induced charges to the sensing electrode. The capacitor primary polarization is induced through the voltage that is applied to the driving electrodes. With the charges accumulated in the sensing electrode, the external electric field is converted into a perturbation to the primary polarization state. By connecting the sensor with a charge amplification circuit, the sensor responses to varying external electric fields are acquired. The sensor has obvious advantages for simple structure, easy signal conditioning circuit and no mechanical motion.