Improved Reference-Free Vibration-Suppressed Optical MEMS Electric Field Strength Sensor

Reliable measurement of the low-frequency and static electric field strength are essential in a number of areas such as atmospheric electricity, high-voltage infrastructure and safety. Such measurements are hard to achieve, since inherent distortions or limited bandwidth render them impossible. This paper shows a distortion-free electric field strength sensor based on a completely passive micromechanical structure with significantly improved suspension for vibration suppression. With this suspension, the responsivity to electric fields was increased while the responsivity to vibrations was decreased by separating the according modes. This trend can be continued to achieve even more robust and more sensitive sensors. The exemplary structure presented in this contribution features a resolution limit of 370 V/m/Hz1/2 and a quotient of 0.39 between the vibrational and the measurement mode frequency.