Study of the shielding effect of a vertical moving shutter micromachined field mill for measuring dc electric field

Abstract

This paper presents the results of studying the shielding effect of a vertical moving shutter micromachined electric field mill. In this design, a set of interdigital sensing electrodes are located in the same plane as the moving shutter, with the shutter's vertical motion enabling modulation of the sensed electric field. The effects of various geometrical parameters of the shutter, including the spacing between the fingers and their width, were simulated to study the collected charge as a function of shutter displacement. For the cases with shutter finger spacings 1.5 to 2 times finger-widths, when the shutter lifted up to a height equal to the comb finger-width, the electrode signal dropped by approximately 22-26%. When the shutter lowered for a height equal to finger-width, the charge increased by approximately 24%. To verify the results of the simulations, one shutter design was selected and fabricated. Thermal actuators were employed to move the shutter vertically, in order to study the shutter shielding effect as a function of displacement. The sensor's mechanical performance test demonstrated 25 µm of displacement when heated to 100 • C. The electric field sensing functionality of the sensor was also tested under an electric field of 9.4 kV m −1 . The vertical motion of the shutter successfully demonstrated its ability to vary the field on the sensing electrodes. An output voltage of 7 ± 0.5 µV was measured per oscillation of the 1.3 × 2 mm shutter for a 25 µm movement. The sensor demonstrated a sensitivity of 0.74 mV kV −1 m −1 .

An anti-charge-interference three-dimensional electric field sensor

“…The measurement of three-dimensional (3D) electric fields is essential in many sectors, including meteorology, electric power, industrial production, and scientific research. In meteorology, the detection of electric fields in thunderstorm clouds allows for the study of their charge distribution and lightning warnings [1][2][3]. The electric fields in thunderstorm clouds have a 3D dynamic nonuniform distribution [4].…”

Electric field sensing characteristics of ZnO/SiO2/Si surface acoustic wave devices

“…The shielding electrode was driven by the piezoelectric effect of piezoelectric ceramics to realize the modulation of electrical signals of the sensing electrode [18]. The University of Manitoba in Canada presented a series of field mill MEMS electric sensors using thermal actuators, including early structures with horizontal move of shielding electrodes [19,20] and later structures with vertical move of shielding electrodes [21,22]. Besides, they also proposed a kind of field drive MEMS electric field sensors with a movable conductive membrane mirror suspended by a set of micro-springs [23][24][25].…”

Resolution-Enhancing Structure for the Electric Field Microsensor Chip

“…The study on the resonant electric field microsensor began in the 1990s, to our knowledge. Since then, the electric field resolution is being improved, from 630 V/m to 20.4 V/m, by various innovative micro sense structures [ 22 , 23 , 24 , 25 , 26 , 27 , 28 , 29 , 30 , 31 , 32 , 33 , 34 , 35 , 36 , 37 ], under the parallel plate calibration. The electric field microchips were mostly exposed to the external environment for test, historically.…”